In general, assessment tools for stigma in mental disorders such as attention deficit hyperactivity disorder (ADHD) are lacking. Moreover, misbeliefs and misconceptions about ADHD are common, in particular with regard to the adult form of ADHD. The aim of the present study was to develop a questionnaire measuring stigma in adults with ADHD and to demonstrate its sensitivity.A questionnaire initially containing 64 items associated with stigma in adults with ADHD was developed. A total number of 1261 respondents were included in the analyses. The psychometric properties were investigated on a sample of 1033 participants. The sensitivity of the questionnaire was explored on 228 participants consisting of teachers, physicians and control participants.Thirty-seven items were extracted due to exploratory factor analysis (EFA) and the internal consistency of items. Confirmatory factor analysis (CFA) revealed good psychometric properties of a 6-factor structure. Teachers and physicians differed significantly in their stigmatizing attitudes from control participants.The present data shed light on various dimensions of stigma in adult ADHD. Reliability and Social Functioning, Malingering and Misuse of Medication, Ability to Take Responsibility, Norm-violating and Externalizing Behavior, Consequences of Diagnostic Disclosure and Etiology represent critical aspects associated with stigmatization. The core symptoms of attention deficit hyperactivity disorder (ADHD), namely inattention, hyperactivity and impulsivity, result in highly externalized behaviors. This externalized behavior can be easily recognized by the environment and may induce misperceptions and misunderstandings about the condition. Moreover, public perceptions concerning ADHD have been shown to be foremost tied to the impression that ADHD is a disorder mainly seen in white middle-class boys suffering preeminent from symptoms of hyperactivity Empirical research on stigmatization revealed that not only physical deviances can set individuals apart and trigger stigmatization. Intrinsic characteristics of the individual such as behavioral deviance have also been found to provoke stigma Research demonstrated that stigmatization of individuals with ADHD has adverse consequences leading to diminished self-esteem and self-efficacious beliefs and ultimately a reduced quality of life Referring to courtesy-stigma, families, relatives or the social network of the target individual with ADHD can also be affected by stigma. For example, more than three-fourths of parents of children with ADHD reported to have encountered stigmatizing situations Considering the impact of stigmatization on the various facets of an individual’s life, the sporadic empirical investigation and the shortness of valid assessment tools measuring stigmatization in ADHD is surprising. This is in accordance with findings by Angermeyer and Dietrich disclosure concerns, negative self-image and concerns with public attitudes. The ASQ represents a valuable contribution in objectifying stigmatizing public beliefs about ADHD and demonstrates psychometric properties of distinct dimensions. However, since it is an adaptation of a disease-specific measure (HIV), no items specifically aiming at stigmatizing beliefs and perceptions related to ADHD are included. For example, the use of medication as a treatment for ADHD is controversially discussed in public and in media Only a few studies made use of survey responses, most likely because of a lack of psychometrically proven questionnaires for the measurement of stigmatization in ADHD. Kellison and colleagues In conclusion, despite stigmatization in ADHD being an important issue, there is a considerable lack of knowledge. Available measures primarily focus on children or do not distinguish between children, adolescents and adults with ADHD. Since it has only recently been acknowledged that ADHD is a condition that can continue from childhood to adulthood, it can be assumed that the public’s knowledge on ADHD in adults is more limited than their knowledge about childhood ADHD. Therefore studies on and measures for the assessment of stigmatization in adult ADHD are of particular significance. The aim of the present study is to enhance knowledge and conceptual clarity on stigmatization in adults with ADHD. A new questionnaire consisting of statements specifically designed to meet public beliefs and perceptions of ADHD in adulthood is developed. Psychometric properties of the questionnaire are explored and the sensitivity of the questionnaire is assessed by investigating differences between stigma responses of individuals with specific knowledge on ADHD  and individuals without specific knowledge.Data were obtained from a total of n = 1261 participants who completed a questionnaire measuring stigma responses towards adults with ADHD. Psychometric properties were explored on a sample of 1033 respondents. 439 of the 1033 respondents were first-year undergraduate psychology students of the University of Groningen, The Netherlands. The remaining participants were recruited via public announcements, word-of-mouth and through contacts of the researchers involved. Respondents’ age ranged from 17 to 79 years with a mean age of 31.3 years (SD = 14.8 years). Mean level of education was 16.4 years (SD = 1.2 years). The sample consisted of 66.0% female and 31.3% male participants with 2.7% missing information. Only 1% of the total sample claimed of never having heard about ADHD and 62.6% of participants stated to know an adult diagnosed with ADHD. On a scale of self-rated knowledge about ADHD ranging from 0  to 10 (expert knowledge), the average score was 4.5 (SD = 2.1). To perform an exploratory factor analysis (EFA) with a subsequent confirmatory factor analysis (CFA), the sample was split into two subsamples (i.e. Subsample 1 and Subsample 2). The allocation of participants to samples has been performed randomly by applying the option of a random selection of cases in SPSS 18. The two subsamples did not differ with regard to their descriptives .A further set of data (n = 228) was collected to demonstrate the sensitivity of the questionnaire by exploring stigma responses of a group of teachers and a group of physicians in comparison to a control group. 77 teachers and 74 physicians were recruited via public announcements, word-of-mouth and through contacts of the researchers involved. All teachers had successfully completed a university study program for teachers and were currently working as teachers for primary or secondary schools. All physicians completed successfully a medicine study program and were currently working as physicians in the health service. A control group (n = 77) was recruited with similar characteristics with regard to age, gender and educational level  .disclosure concerns, negative self-image and concerns with public attitudes. On the other hand, Haslam pathologizing, moralizing, medicalizing and psychologizing. A total of 64 items has been generated. Items were randomly arranged in the questionnaire to control for possible rang order effects. The questionnaire was constructed using a 6-point-Likert-scale with higher scores indicating higher stigma . Prior to the 64 items, eight inventorial questions were asked to obtain general background information including descriptive information of respondents . Information about participants’ self-rated knowledge concerning ADHD and their familiarity with adults with ADHD  was obtained at the end of the questionnaire. These questions were introduced at the end to prevent biased responses of participants to the 64 items.Based on (I) an extensive literature study on social perceptions, myths and stigma in ADHD, (II) the personal clinical experience with adults with ADHD of the researchers involved in this study and (III) patient interviews about their experiences, a deductive approach was applied for initial item generation All participants were invited to take part in the study on a voluntary basis. Participants received no reward for participation with the exception of undergraduate students who were credited toward a research requirement. The time to complete the questionnaire was estimated to take around twenty minutes. Participants were informed about the aim of the study and it was emphasized that all data will be analyzed anonymously. The study was approved by the ethics committee of the University of Groningen, The Netherlands.The study was approved by the Ethical Committee Psychology (ECP) affiliated to the University of Groningen, the Netherlands. Before participating, all participants were informed about the aims of the study. Participants were required to read and acknowledge an information sheet prior to completion of the questionnaire. Formal written consent was not sought for adult participants; submission of completed questionnaires was taken as implied consent. Since participants with an age of 17 years were included (n = 2), written informed consent was obtained from these participants as well as their parents prior to inclusion.Subsample 1 with a subsequent confirmatory factor analysis (CFA) on Subsample 2 in order to identify distinct factors of stigma in adults with ADHD. For EFA, a principal component analysis (PCA) was applied using orthogonal rotation (Varimax). Subsample 1 consisted of 516 participants. According to the classification proposed by Comrey and Lee very good” sample size.Exploratory factor analysis (EFA) was performed on Cronbach’s α was calculated for the total scale and the subscales (factors) of the questionnaire as a measure of internal consistency.Subsample 1, confirmatory factor analysis (CFA) was conducted on Sample 2 using the program LISREL 8.8 for Windows Subsample 2 (n = 517) exceeded the criterion of a minimum sample size of 200 respondents for CFA considerably To replicate the proposed factor structure model by the EFA on The factor structure was examined by the following goodness-of-fit statistics: Chi-Square value with corresponding p-value, normed Chi-Square (χ/df), Root Mean Squared Error of Approximation (RMSEA), 90%-confidence interval of the RMSEA, Standardized Root Mean Square Residual (SRMR) and Comparative Fit Index (CFI).Chi-Square value with its corresponding p-value belongs to the class of absolute fit indices, measuring how well a specific model fits in comparison to no model at all. The Chi-Square statistics assess the magnitude of discrepancy between the sample and fitted covariance matrices normed Chi-Square which takes the degrees of freedom (χ/df) into account. In the present study, therefore, less weight was given to the Chi-Square test than to the descriptive measure of the normed Chi-Square. The smaller the ratio of the normed Chi-Square the better is the fit of the model. Recommendations for an acceptable ratio range from 5.0 to 2.0 with a good fit below a value of 3.0 The Root Mean Squared Error of Approximation (RMSEA) is an indicator of the discrepancy between the model and data covariance matrices per degree of freedom The Standardized Root Mean Square Residual (SRMR) represents the square root of the difference between the residuals of the sample covariance and the hypothesized covariance model. Values of the SRMR range from 0 to 1 with acceptable models obtaining values up to.08 The Comparative Fit Index (CFI) is a revised version of the Non-Normed Fit Index (NNFI), also known as Tucker-Lewis Index The The goodness-of-fit statistics of the factor model as proposed in EFA of the present study were compared to the cut-offs and recommendations as cited above. Additionally, fit statistics of the multitrait model were compared to the fit statistics of a single common factor model which served as a competing model. Once the overall fit of the model has been evaluated, each model coefficient was individually examined for its degree of fit. This was achieved by t-tests testing the null hypothesis that the true values of specified factor loadings are zero. All items with non-significant factor loadings (p≤.05) were deleted from further analysis Stigmatization was analyzed in descriptive statistics on the sample (n = 1033) on the basis of the extracted factor structure. Subsequently, a dependent sample ANOVA with post-hoc pairwise comparisons was performed to assess differences in stigmatization between subscales. The effects of gender and age on stigma were assessed with t-tests for independent samples and Pearson product-moment correlations, respectively. Statistical tests were calculated separately on extracted stigma subscales which led to α-accumulation. To counteract the problem of multiple comparisons, the significance level α was adjusted by using a Bonferroni correction. Moreover, effect sizes (Cohen’s d) were calculated for all comparisons. Following Cohen’s guidelines for interpreting effect sizes Stigmatization of teachers, physicians and control participants was explored on the basis of the extracted factor structure. A multivariate analyses of variance (MANOVA) with post-hoc pairwise comparisons (Scheffé) was calculated to compare stigmatization between the three groups on each subscale and on the total scale. Moreover, effect sizes (Cohen’s d) were calculated for all comparisons. Following Cohen’s guidelines for interpreting effect sizes Subsample 1. A Kaiser-Meyer-Olkin value of.86 supported sampling adequacy for the analysis and can be categorized as meritorious according to Kaiser 2(2016) = 8258.3, p<.001). PCA using orthogonal rotation (Varimax) initially identified 17 components meeting Kaiser’s criterion of an eigenvalue >1 which explained 61.1% of the total variance. Items were initially retained when they loaded on a factor with a minimum loading of.40 but did not load to any other factor higher than.39. However, on the basis of a scree plot inspection and calculations of the internal consistency , it was justified to extract six of the initial components with a total of 37 items for further exploration. All of the six components had eigenvalues ranging from 2.64 to 5.47. eigenvalues and the percentage of explained variance for each of the six components. The six components of the PCA were interpreted as the following subscales of the questionnaire: Reliability and Social Functioning of adults with ADHD (factor 1), Malingering and Misuse of Medication (factor 2), Ability to Take Responsibility (factor 3), Norm-violating and Externalizing Behavior (factor 4), Consequences of Diagnostic Disclosure (factor 5) and Etiology of adult ADHD (factor 6).Psychometric properties were assessed by applying EFA on The overall scale reliability  of the 37 items was high (Cronbach’s α = .91). The scale reliabilities of the six subscales (Cronbach’s α) ranged between.61 and.87, with.60 indicating the minimum acceptable and 0.80 indicating good reliability. 2 (614) = 1763.68; p<.01). More crucial, the normed Chi-Square value was within a range indicating a good fit (χ2/df = 2.87). Both a RMSEA of.06 and its 90%-confidence interval  also pointed to a well-fitting model. The SRMR of.07 was below the recommended cut-off of.08 and therefore further supported the model fit. Finally, the incremental fit index (CFI = .93) also revealed an acceptable model fit. In summary, the CFA resulted in a satisfactory fit for the present 6-factor model. The proposed 6-factor model outperformed a single common factor model (χ2 (629) = 2680.78 p<.01; χ2/df = 4.3, RMSEA = .099, 90%-CI for RMSEA = ; SRMR = .082; CFI = .87) in all indices. To investigate each model coefficient individually, t-values for factor loadings were inspected. Significant loadings were found for each item (p<.01). Therefore, no items had to be excluded.Regarding the overall fit of the model, the Chi-Square statistics led to rejection of the model (χConsequences of Diagnostic Disclosure) followed by subscale 1 , subscale 4 , subscales 3 (Ability to Take Responsibility) and 6 (Etiology) and finally subscale 2 . Effect sizes of pairwise comparisons ranged from negligible size to large size  = 295.2; p<.001). Post-hoc pairwise comparisons revealed significant differences between all pairs of subscales with the exception of the comparison between subscale 1 and subscale 4 and between subscale 3 and subscale 6 . Particirge size .For the analysis of the effects of gender and age, a Bonferroni adjusted significance level of p = .0083 was applied because of multiple comparisons/correlations . Stigma scores of female respondents  were compared to the scores of male respondents  using t-tests for independent samples . Male reStigma responses of teachers, physicians and control participants are presented in Empirical research directly addressing stigma in ADHD is sparse. One difficulty in studying this topic is the lack of appropriate measures. Therefore, a new questionnaire on stigma in adults with ADHD has been developed in the present study. The aims of this development were (I) to identify dimensions that specifically meet stigmatizing issues persons with ADHD are confronted with, (II) to transfer the knowledge gained from research on childhood ADHD to the adult population, and finally (III) to examine the sensitivity of the questionnaire in measuring differences of stigmatizing attitudes between groups by comparing stigma responses of teachers, physicians and matched control participants.The questionnaire consists of 37 items directly addressing stigmatizing beliefs on adults with ADHD. Exploratory factor analysis (EFA) revealed a 6-factor structure which was empirically confirmed by a confirmatory factor analysis (CFA). The devised 6-factor structure has been supported in overall fit indices and by inspecting each model coefficient individually. Furthermore, the 6-factor structure has been shown to be superior to a single common factor model.Consequences of Diagnostic Disclosure.Research demonstrated that the mere label of a psychiatric condition can trigger stigmatization Reliability and Social Functioning. This factor may reflect the difficulties of individuals with ADHD in maintaining social relations, friendships and partnerships Participants’ responses to statements that adults with ADHD are not reliable, less trustworthy, self-focused, egoistic and careless about other’s problems have been found to load on a common factor which has been labeled Ability to Take Responsibility encompasses statements, which refer to situations in which individuals with ADHD take over the responsibility for another individual, a family or a business . Getting stigmatized on this factor implies doubts about the social, academic and vocational abilities of the person with ADHD. Adverse academic outcomes and adverse career developments might be possible consequences. In fact, it has been shown that persons with ADHD often encounter a range of problems in the occupational setting, comprising peer relational problems accompanied with adverse academic and vocational outcomes The factor Malingering and Misuse of Medication. Stigmatizing believes point to severe doubts about the existence of ADHD in public which can lead to detrimental consequences for affected individuals. For example, the necessity for treatment can be questioned, the access to treatment can be hindered, and help seeking behavior may become discouraged in the individual with ADHD. Furthermore, effective psychosocial and pharmacological intervention strategies may be refused. In conclusion, adverse adherence to and low efficacy of treatment might result.Another important issue in explaining the emergence of stigmatization in ADHD lies in the doubts concerning the existence of ADHD as a disorder Norm-violating and Externalizing Behavior refers to society’s understanding of ADHD which is dominated by the occurrence of behavioral disturbances associated with the condition, in particular with the preeminent hyperactive-impulsive symptoms which are a defining characteristic of childhood ADHD The factor labeled Etiology and implies common stigmatizing beliefs about the etiology of ADHD (e.g. in claiming that adults with ADHD do not engage enough in sports or that extensive exposure to video games and TV shows cause ADHD). The importance of this dimension is indicated by findings showing that knowledge about the etiology of mental disorders, such as ADHD, may adjust stigmatizing beliefs Finally, a dimension has been identified concerning the causes of the condition. This factor has been labeled The present study did not reveal a factor focusing on medication use. This might appear surprising, since misperception and stigmatizing beliefs about long-term effects of medication in ADHD were repeatedly reported Malingering and Misuse of Medication). Significant more stigmatization with small effects were found on subscale 3 (Ability to Take Responsibility) and subscale 6 (Etiology). Representative items for these factors are item 3 for subscale 2 (“Many adults with ADHD simulate the symptoms”), item 2 for subscale 3 (“I would mind if my investment advisor had ADHD”) and item 23 for subscale 6 (“Adults with ADHD do not engage enough in sports”). Stigma responses on these subscales were exceeded by stigma scores on subscale 1 , subscale 4  and subscale 5 (Consequences of Diagnostic Disclosure). These differences were of small to large size. Within these subscales, high stigmatizing responses were observed on item 15 (“Adults with ADHD care less about other’s problems”) and item 6 (“People’s attitudes about ADHD make persons with ADHD feel worse about themselves”). These results shed light on the trouble persons with ADHD are assumed to have in social life, for example with making friends, being trustworthy, being empathic and caring about other peoples’ problems. These findings refer also to the public’s assumption of socially inappropriate behavior of persons with ADHD which might result in a lower social status. Moreover, the mere diagnostic label and its disclosure is believed to have adverse effects on affected individuals’ self-esteem and general well-being as reflected in high stigmatizing responses. In this context, educational programs aiming to inform the general public about ADHD might be of particular value in reducing the stigmatizing label bias. Previous research already demonstrated that an increase of knowledge about ADHD  is in general an effective approach in reducing stigmatizing beliefs The overall level of stigma was found to be low to moderate as reflected in negative values for all subscales. Even though the absolute value is difficult to interpret due to lacking reference values, conclusions can be drawn on the basis of comparisons of stigmatizing responses between subscales. Except of two comparisons , stigma responses on all subscales differ significantly from each other. Effect sizes between subscales ranged from negligible to large effects, supporting the notion that different dimensions of stigmatization towards adults with ADHD were measured. The lowest stigma responses could be shown on subscale 2 . This is supported by the finding that an increasing number of students present themselves to specialists at the post-secondary-level because of ADHD symptoms In line with previous research Reliability and Social Functioning, Malingering and Misuse of Medication and Norm-violating and Externalizing Behavior. Physicians showed significantly less stigmatization on the subscales Malingering and Misuse of Medication as well as Etiology. Although teachers and physicians did not differ from control participants on the total scale, the present results indicated that teachers and physicians are more sensitive to stigma in ADHD, at least in some aspects. Moreover, different patterns of differences between teachers and physicians in comparison to control participants were found, as indicated by lower stigma of teachers but not physicians on the subscales Reliability and Social Functioning and Norm-violating and Externalizing Behavior. However, lower stigma responses were found concerning the etiology of ADHD in physicians but not teachers. Considering the educational background of teachers and the expert knowledge of physicians, it is not surprising that physicians were more sensitive with respect to the etiology of ADHD than the general population, while teachers were more sensitive to the functioning of individuals with ADHD. Teachers of course experienced that children with ADHD can learn to cope with their problems and difficulties under certain circumstances, that they have social skills and that they can take over responsibilities. Teaching and mentoring these children over a longer period of time, sometimes even till early adulthood, might provide them with a unique insight in the development of individuals with ADHD. Consequently, teachers might see much more the potential in individuals with ADHD than the general population, making them less prone to stigmatize individuals with ADHD. The different profiles observed therefore most likely reflect the effect of different trainings and experiences between more experienced groups (teachers and physicians) and the general population (control participants). These different profiles, however, also point to the existence of different qualities/dimension of stigmatization. Finally, the detection of these differences also indicates that the questionnaire presented appears to be sensitive with regard to stigmatization of adults with ADHD.When studying stigmatization towards a developmental disorder such as ADHD, people working in the educational or health care sector are of particular interest. Teachers, on the one hand, received a specialized training in educational sciences and have contact to a wide range of youngsters and accompany them in their development from childhood through adolescence into adulthood. Therefore, teachers can be assumed to be more sensitive towards developmental disorders such as ADHD and to be less prone to stigmatizing attitudes towards those affected by these disorders. Physicians, on the other hand, successfully completed a university study program in medicine and have a broad understanding of factors underlying human behavior. Moreover, stigma is a concept that is quite salient in medicine, since individuals with many different physiological, psychosomatic or psychological conditions experience stigmatization. Consequently, physicians have a higher chance to get in contact with people experiencing stigmatization than the general population. Furthermore, many physicians might even be informed by their professional associations, colleagues, conferences or any other additional training about the existence of ADHD in adulthood and the problems involved. Therefore, physicians are presumably also more sensitive with regard to stigmatizing beliefs and attitudes. However, analysis of the present data revealed that teachers, physicians and control participants did not differ on the overall level of stigmatization. Nevertheless, teachers and physicians could be found to show lower scores than control participants on certain aspects of stigma. Significantly lower stigma responses were found for teachers in statements focusing on Reliability and Social Functioning, Malingering and Misuse of Medication, Ability to Take Responsibility, Norm-violating and Externalizing Behavior, Consequences of Diagnostic Disclosure and the Etiology of adult ADHD appear to be crucial dimensions when dealing with the construct of stigma in ADHD. The application of the questionnaire may support in the process of the development of effective prevention and intervention strategies against stigmatization of adults with ADHD and persons with related psychiatric conditions.In the present study, a new questionnaire with six subscales assessing stigmatization in adults with ADHD has been described. The psychometric properties of these subscales were carefully evaluated and the factor structure was replicated as suggested by Hinkin


It is well-established that ADHD children have deficits in executive functions such as performance variability and sustained attention. It has been suggested that these deficits are intermediate phenotypes. Hyperactivity, a core symptom of ADHD, has not yet been explored as a potential intermediate phenotype in ADHD. The computerized Quantified behavior Test (QbTest) is a combined continuous performance and activity test that assesses hyperactivity, inattention, and impulsivity separately. The aim of the present study was to (1) investigate the utility of objectively measured motor activity as a potential intermediate phenotype in ADHD, and (2) explore intermediate phenotypes for ADHD at the factor instead of single variable level.Forty-five ADHD children, 22 non-affected siblings, and 45 unrelated controls with no family history of ADHD performed the QbTest. Effects of familiality as well as influences of age and gender on QbTest symptom dimensions were tested.ADHD children showed the greatest impairments on all three QbTest factors, followed by their non-affected siblings, with control children showing the lowest scores. Group differences between the non-affected siblings and controls were only significant for the motion tracking-based Hyperactivity factor. Results were independent of age and gender.Hyperactivity assessed by a motion tracking system may be a useful intermediate phenotype in ADHD. Prospective research should use larger samples to further examine the QbTest factors, especially the motion tracking-based Hyperactivity factor which may be a candidate for an intermediate phenotype in ADHD. Attention-Deficit/Hyperactivity Disorder (ADHD) is characterized by a triad of symptoms— age-inappropriate levels of hyperactive, inattentive, and impulsive behavior—that lead to severe impairments . ADHD isIntermediate phenotypes have proven especially helpful for unraveling complex etiologies of psychiatric disorders . IntermeSeveral key criteria have been proposed for intermediate phenotypes  in ADHD, including (1) a robust association with the disorder, (2) evidence of heritability, and (3) unaffected family members of affected individuals showing a higher rate of intermediate phenotype expression than individuals from the general population ,10. AddiTo date, research on neuropsychological intermediate phenotypes for ADHD has primarily focused on executive dysfunctions (ED) such as sustained attention, response control, and performance variability. There is considerable evidence for ED, like reduced inhibitory control and sustained attention, in ADHD children . In partIncreased motor activity is a core feature of ADHD and predicts (beyond the age of four) a diagnosis of ADHD at age nine . ObjectiThe QbTest  is a comUsing factor scores to aggregate data has been shown to be a highly effective strategy in neurogenetic research  and clinThe present study investigates the following three technically assessed QbTest factor scores as potential markers to improve phenotype definition: Inattention, Hyperactivity, and Impulsivity . To our All participants were recruited in the context of a therapy study on ADHD at the department of clinical psychology and psychotherapy, Philipps University, Marburg, Germany for details on this study, see . FamilieIn total, 112 children  aged 7–16 years  were included in the study. The sample consisted of 45 ADHD children, 22 non-affected siblings, and 45 healthy controls  = 10.5, p = .005). In the ADHD group, 78% of the children were male, while only 59% and 44% were male in the non-affected sibling and control groups, respectively. In addition, the non-affected sibling group differed from the other two groups in age (χ2(2) = 50.3, p < .01), as siblings tended to be older than the ADHD and control children. We therefore used age- and gender-adjusted QbTest values  to calculate the QbTest factor scores, and also included both variables as covariates.The ADHD group significantly differed from the non-affected sibling and healthy control groups with respect to gender  and activity test  that assAll analyses were conducted using SPSS 19.0. All variables were examined for accuracy of data entry and missing values prior to the analyses. No missing values were found. The Kolmogorov-Smirnov test did not reach significance for any of the three factors used as dependent variables in the multivariate analyses, thus normal distribution of the data can be assumed.To control classification and separability of the three groups, we conducted t-tests for each group to determine whether group means were significantly different from our cut-off score in the Conners’ Parent questionnaire .p < .08 and significance as p < .05. Pair-wise comparisons were conducted to further explore group differences and confirm the locus of effects. Effect sizes (ηp2) are reported when appropriate and interpreted according to Cohen [2; medium: 0.06 ≥ η2; and large: η2 ≥ 0.14 effects. For pair-wise comparisons, we used the post-hoc Scheffé test because it is most strict when sample sizes vary across groups. Additionally, non-parametric statistics  were performed to test intergroup differences and thereby control multivariate test results. For non-parametric tests, r is reported as the effect size and is interpreted as 0.1 = small, 0.3 = medium, and 0.5 = large [The three QbTest factors were computed according to factor analytic results . Age- anto Cohen ; small:  = large .Even though effects of age and gender should have minimal influences because age- and gender-normed Q-values were used to calculate factor scores, we still performed a MANCOVA with the QbTest factor scores as dependent variables, group  as a between subject factor, and age and gender as covariates.Finally, to further explore effects of familiality, we conducted trend analyses across the three groups to test whether non-affected siblings show intermediate impairments between ADHD children and healthy controls. A linear trend in the absence of a residual quadratic trend would indicate familiality of the given construct. A residual quadratic trend would indicate that the non-affected siblings were more similar to either the ADHD or control group .p < .001). The sibling group , and control group  both scored significantly lower than 63.The ADHD group scored significantly higher than 63 on the Conners’ Parent ADHD index  = 7.75, p < .01,  = 15.47, p < .01,  = 14.57, p < .01,  = 9.94, p < .01, 2(2) = 24.4, p < .01; Impulsivity: χ2(2) = 22.7, p < .01; Hyperactivity: χ2(2) = 16.5, p < .01).The MANOVA performed on the QbTest data showed a large and significant main effect of group . This was supported by results from the non-parametric Mann-Whitney-U test and effect sizes ranged from medium to large . As expected, ADHD children were significantly more hyperactive than control children while performing the QbTest, and also showed more impulsive and inattentive behaviors  confirmed significant group differences between the ADHD and control group for all three factors ps < .0. This wap = .039), such that non-affected siblings showed an intermediate level of motor activity between their ADHD siblings and healthy controls. This effect was confirmed by non-parametric results that had a medium effect size , and can thus be interpreted as preliminary evidence for the utility of the Hyperactivity factor as a candidate intermediate phenotype for ADHD. The difference between the non-affected sibling and healthy control groups did not reach significance for the Impulsivity factor (p = .128). The non-parametric Mann-Whitney-U test revealed a trend towards a significant difference in behavioral impulsivity between non-affected siblings and healthy controls . Furthermore, a post-hoc Scheffé test revealed no significant difference between the non-affected sibling and control groups on Inattention factor scores (p = .962), and group means for those two groups were very close, as shown in Figure p < .01), indicating that non-affected siblings were more similar to the healthy controls than to their biological ADHD siblings in terms of inattention.Hyperactivity factor scores were significantly different between non-affected siblings and controls  = 0.61, p = .435,  = 1.66, p = .201,  = 1.79, p = .184,  = 1.46, p = .230,  = 0.48, p = .226,  = 0.43, p = .514, The MANCOVA revealed the following results for age and gender. Hyperactivity factor scores were not significantly influenced by either age  = 19.09, p < .01) without a quadratic trend  = 0.79, p = .38) indicating that, as predicted, the non-affected sibling group showed an intermediate level of motor activity compared to the more hyperactive ADHD group and the less hyperactive healthy control group. Hence, motor activity showed evidence of familiality. For Inattention factor scores, there was a linear trend  = 26.95, p < .01), and the quadratic trend also reached significance  = 3.98, p = .05). Inattention levels were very similar between the non-affected sibling and control groups  = 29.11, p < .01) in the absence of a quadratic trend  = 0.02, p < .88), indicating that the three groups showed the typical intermediate phenotype pattern across behavioral impulsivity levels.Trend analyses for Hyperactivity factor scores revealed a strong linear trend  as potential intermediate phenotype markers for ADHD. This is the first study to explore motion tracking-based motor activity in ADHD siblings. Moreover, we examined neuropsychological intermediate phenotypes for ADHD at the factor, rather than single variable, level for the first time. We hypothesized that ADHD children would show the greatest impairments in task performance and that their non-affected siblings would show intermediate impairments compared to a control group of children with no family history of ADHD.Confirming our first hypothesis, children with ADHD showed substantially greater impairments compared to children from the control group across all three QbTest factors. They were more inattentive and impulsive, and showed higher levels of motor activity while performing the QbTest.The Hyperactivity factor consisted of the following five QbTest variables: Time Active, Distance, Area, Microevents, and Motion Simplicity ,23. ADHDThe Inattention factor was composed of three QbTest variables: RT, RT variability, and Omission errors. ADHD children reacted more slowly and variably and they also committed more omission errors than did children in the control group. RT variability and omission errors have repeatedly been shown to be higher in children with ADHD compared to healthy controls ,15,24. TThe Impulsivity factor consisted of three QbTest variables: Commission errors, Multiresponses, and Anticipatory responses. ADHD children committed more commission errors , and had a higher percentage of multiresponse and anticipatory responses than controls. Commission errors have been defined as a measure of deficient response inhibition and have been shown to be substantially elevated in ADHD children compared to controls . This isWe also hypothesized that children from the non-affected sibling group would show intermediate impairments—between ADHD and healthy control children—but would be significantly different from controls.We found a strong linear trend across group means for the motion tracking-based Hyperactivity factor. As expected, non-affected siblings showed an intermediate level of motor activity between ADHD children (highest activity scores) and controls (lowest activity scores). Moreover, there was a significant difference between the non-affected sibling and control groups. Taken together, the presence of increased motor activity not only in ADHD children but also in their non-affected siblings indicates that the QbTest Hyperactivity factor fulfills two important criteria for an intermediate phenotype measure : it co-oWe found a linear trend across groups, with ADHD children showing greatest, non-affected siblings showing intermediate, and control children showing the least impairment for the Inattention and Impulsivity factors. Group means for the non-affected sibling and control groups did not significantly differ for either the Inattention or Impulsivity factors. Note, however, that the present study may have been underpowered for detecting small to medium effects between non-affected siblings and control children , and hence subsequent studies should investigate whether QbTest factors are intermediate phenotypes using larger groups.Results also showed that non-affected siblings performed very similarly to children from the control group with respect to the Inattention factor, which was supported by a significant quadratic trend. This contrasts with other findings suggesting that RT variability , omissioFurthermore, we explored whether group differences were independent of age and gender. Results clearly showed that none of the three QbTest factors were influenced by age or gender, indicating that adjusting by age and gender norms provided in the QbTest was successful. Finally, it should be noted that while intermediate phenotypes in ADHD can be assessed and established on different levels , these lie on a continuum from the genetic underpinnings of the disorder to biologically rooted intermediate phenotypes to neuropsychological variables and factor scores to the observation of behavior representing the full heterogeneity of the ADHD phenotype. The QbTest factor scores are based on the neuropsychological level of the disorder and may represent a marker for ADHD that could ultimately help to improve phenotype definition.The following limitations of this study should be noted. First, as discussed above, age and gender distributions differed between the groups in our study. Boys were overrepresented in the ADHD group, and mean age was higher in the non-affected sibling than ADHD and control groups. However, analyses controlling for age and gender did not reveal significant influences of age and gender, and the higher number of boys in the ADHD group reflects the male to female ratio in ADHD -4.r > .44), it is likely that non-affected siblings and controls who show elevated QbTest scores also have higher ADHD behavior ratings than children with lower QbTest scores. As described above, we controlled classification and separability of the three groups by testing group means against our Conners’ Parent questionnaire cut-off score (T = 63). The ADHD group scored significantly higher, while the other two groups scored significantly lower, than the cut-off score. Thus, overall, the groups adequately differed with respect to parent ratings of ADHD-related behavior.Second, we did not administer the clinical interview to non-affected siblings and controls. Additionally, Conners’ Teacher Questionnaires were missing for some children in the non-affected sibling and control groups. However, known formal diagnosis of ADHD and other childhood disorders were assessed in the biographical parent questionnaire and participation in the control group was explicitly advertised as seeking children without any ADHD-related behavior problems. Nevertheless, five children in the non-affected sibling group and two children in the control group showed high Conners’ Parent ratings (T > 63). As parent ratings of ADHD behavior and QbTest factor scores were significantly correlated  the utility of technically assessed motor activity as an intermediate phenotype in ADHD, and (2) the advantage of neuropsychological factor scores over single variable scores.Establishing risk markers in ADHD is highly desirable as it could reduce heterogeneity at the symptom level and thereby help clarify ADHD classification and diagnosis. The present study is the first to explore the utility of factor scores from the neuropsychological QbTest as potential intermediate phenotypes for ADHD. ADHD children exhibited the greatest impairment on all three factors, followed by their non-affected siblings, with control children showing the least impairment. However non-affected siblings only differed significantly from controls on the motion tracking-based Hyperactivity factor. Results were independent of age and gender. This provides important preliminary information concerning the utility of motor activity as a new intermediate phenotype for ADHD.The authors declare no competing interests.VR planned the study, recruited participants, analysed the data and wrote a first draft of the MS. MS planned the study, recruited participants, and proof-read the MS. WR supervised study planning and proof-read the MS. HC supervised the study, worked on the MS draft and the final MS version, and proof-read the MS. All authors read and approved the final manuscript.


Culture under low oxygen or extracellular matrix (ECM) improves proliferation of MSCs in several species. We tested the hypothesis that culture under low oxygen in combination with ECM prepared from mouse embryonic fibroblast (MEF-ECM) could be used to purify proliferative mMSCs, and to reduce oxidative damage and maintain their chromosomal stability.Isolation of mouse MSCs (mMSCs) with normal ploidy from bone marrow remains challenging. mMSCs isolated under 20% O2 resulted in immortalization of mMSCs, showing extensive chromosome abnormalities, consistent with previous studies. In contrast, culture under low oxygen (2% O2) improved proliferation of mMSCs and reduced oxidative damage, such that mMSCs were purified simply by plating at low density under 2% O2. MEF-ECM reduced oxidative damage and enhanced proliferation of mMSCs. However, these isolated mMSCs still exhibited high frequency of chromosome abnormalities, suggesting that low oxygen or in combination with MEF-ECM was insufficient to fully protect mMSCs from oxidative damage. Notably, antioxidants  and N-acetylcysteine (NAC)) further reduced DNA damage and chromosomal abnormalities, and increased proliferation of mMSCs. mMSCs isolated by the combination method were successfully used to generate induced pluripotent stem (iPS) cells by ectopic expression of Oct4, Sox2, Klf4 and c-Myc.Optimization of culture conditions under 20% OWe have developed a technique that allows to reduce the number of karyotypic abnormalities for isolation of primary mMSCs and for limited culture period by combination of low oxygen, MEF-ECM, antioxidants and low density plating strategy. The effectiveness of the new combination method is demonstrated by successful generation of iPS cells from the isolated mMSCs. However, a culture system for mMSCs still is needed to prevent all the anomalies, especially after a long-term culture period. Furthermore, mouse cells are more sensitive than human cells to oxygen [2 has been associated with increased oxidative DNA damage [2) could be especially vulnerable to oxidative damage, leading to chromosome instability and finally immortalization and transformation. Indeed, low oxygen has been consistently shown to improve proliferation of MSCs in several species including human, rat, and porcine [Another characteristic of mMSCs is their high chromosomal instability ,15-19. Bironment ; cultureo oxygen , and immA damage . Thus, m porcine -26, and  porcine -29.MSCs seeded onto extracellular matrix (ECM) show enhanced proliferation. ECM or components of ECM such as laminin and collagen could increase expansion ability of human MSCs -32. Hyal2 condition and obtained only immortalized mMSCs lines with frequent chromosome abnormalities and even with tumorigenic potentials. Following extensive experimentation, we developed an improved method to purify mMSCs with normal ploidy by seeding marrow cells directly onto MEF-ECM at 5 × 104 cells/cm2 under 2% O2, with addition of antioxidants in the primary culture.Initially, we attempted to isolate mMSCs under classical 20% O2. Efficiency of isolation of mMSCs was compared by culture in wells coated with gelatin or fibronectin or uncoated wells, different basal medium including DMEM and RPMI 1640, fetal bovine serum of 10-20% of various sources, a variety of growth factors including PDGF, EGF, LIF [in vivo tumorigenicity using immunodeficient nude mice. One cell line  generated osteosarcoma-like tumor  significantly improved the proliferation of mMSCs and the cell number increased approximately ten-fold  under culture at 2% O2, compared to 20% O2  appeared as fibroblasts-like cells, similar to IDmMSCs cultured under 2% O2. Moreover their epitopes were also similar to those of IDmMSCs, negative for hematopoietic marker CD45 and CD11b, and endothelial marker CD31 and Flk-1, but positive for Sca-1 and CD44  was much higher than that cultured on plastic as control (CmMSCs). EmMSCs were more confluent, showing smaller cells, compared to CmMSCs at day 4  exposure [2AX intensity compared to CmMSCs  in mMSCs. ROS generated during normal oxidative metabolism may cause damage to DNA and contribute to genomic instability . Cellulaexposure -44. EmMSs Figure , suggests Figure . Thus, mThe above data show that combination of low oxygen and MEF-ECM can be used to obtain relatively pure proliferative mMSCs at early passages. We then examined whether the isolated mMSCs had normal karyotype. About 56% (28/50) metaphases prepared from EmMSCs at passage one had normal number of 40 chromosomes Table , in contThe chromosome abnormalities in early passage mMSCs indicate that culture under low oxygen is not sufficient to protect mMSCs from oxidative damage. To further decrease possible accumulation of oxidative damage and therefore improve long-term viability of mMSCs, a combination of two antioxidants (800 μM PBN and 5 mM NAC) was used for initial isolation of mMSCs. PBN is a free radical spin trapping agent and has been shown to reduce oxidative damage and extend lifespan of human fibroblasts and peritoneal mesothelial cells ,46. NAC 2O2 at the concentrations that did not cause immediate cell death and found that H2O2 reduced cell proliferation  proliferated to passage 8 without obvious growth arrest  of cells analyzed, while only 58% of mMSCs cultured on plastic as control had normal karyotype  Figure . Forty e2 in DMEM or α-MEM, supplemented with 10-20% fetal bovine serum. Isolation and long-term culture of mouse MSCs under these classical culture conditions has been found problematic, compared to that of other species [2. However, mMSCs can be purified simply by culture under 2% O2, mainly attributable to significantly improved proliferation of mMSCs and reduced oxidative damage. Also, passaging by harvesting only easily detached cells without pipetting [2 improves purification and proliferation of mMSCs, such that a purer population of mMSCs could be obtained only 9 days after initiation of culture.MSCs are routinely cultured under 20% O species . Consist species , our datipetting ,48 and sECM prepared from MEF further expands mMSCs and reduces oxidative damage. This might be explained by more undifferentiated state and higher antioxidant defence capacity of mMSCs expanded by MEF-ECM. Stress defence of stem cells is usually superior to that of differentiated cells , and ECMin vitro culture of bone marrow cells. Consistently, several groups have already reported chromosome abnormalities in bone marrow derived mMSCs cultured under 20% O2 [2 suggest that low oxygen alone or in combination with MEF-ECM is insufficient to protect mMSCs from oxidative damage and chromosome instability. But increased rates of normal chromosomes found in EmMSCs than in CmMSCs suggest a possible role of MEF-ECM in reducing chromosome instability of mMSCs.However, mMSCs cultured on either plastic or MEF-ECM show high frequency of chromosome abnormalities. Further, chromosome abnormalities are found just upon primary r 20% O2 ,15-19. Rr 20% O2 , suggestr 20% O2 . ChromosAntioxidants might confer mMSCs additional antioxidant defence capacity. A combination of two antioxidants (PBN and NAC) significantly reduces spontaneous MN and increases normal karyotype of primary mMSCs, in association with increased proliferation of mMSCs. Particularly, mMSCs could be expanded continuously on MEF-ECM without noticeable growth arrest for at least 8 passages  and stored at 4°C for subsequent uses.MEF was isolated from 13.5 dpc embryos of C57BL/6 × DBA/2 hybrid background and maintained as described . For pre5 cells/cm2 in 2.5 ml DMEM containing 20% fetal bovine serum (Hyclone) and 1% penicillin-streptomycin antibiotics (Invitrogen). In some experiments, a combination of antioxidants  and 5 mM N-acetylcysteine (NAC)) were added in the medium. In others, bone marrow cells were seeded directly onto MEF-ECM-coated wells. Cells were cultured at an atmosphere of 2% O2  at 37°C. Non-adherent cells were removed after 24 hours by washing twice with phosphate-buffered saline (PBS), and fresh medium added. At day 5-6, adherent cells were treated with 0.25% trypsin/0.02% EDTA (Invitrogen) for 3 min at 37°C. The cells lifted within 3 min were collected and replated at 1000 cells/cm2 onto uncoated 6-well plates or plates coated with MEF-ECM. The medium was replaced every 2-3 days until cells reached 90% confluence. Subsequent passaging was carried out using the same conditions.Young B6D2F1 mice (3-5 weeks old) were sacrificed by cervical dislocation using protocol approved by the Institutional Animal Committee. Whole bone marrow was harvested by flushing femurs and tibiae as described . The mar2, the marrow cells were plated at a higher density of 2 × 106 cells/cm2, and subcultures were performed at a split ratio of 1:3 when cells reached 90% confluence.For initial experiments to optimize culture conditions under 20% O2.For immunodepletion experiments, retrieved primary mMSCs were stained with PE-conjugated anti-CD45 and anti-Ter119 antibodies (Miltenyi Biotec), and then stained with anti-PE magnetic microbeads (Miltenyi Biotec) and immunodepeleted according to the manufacturer's instruction. Cells negative for CD45 and Ter119 were seeded onto 6-well plates at 10, 000 cells/cmTo induce osteogenic differentiation, 70-80% confluent mMSCs were incubated in osteogenic medium  for one week with medium changed once, based on a method with slight modification . The celTo induce adipogenic differentiation, 70-80% confluent mMSCs were incubated in adipogenic medium  and 60 μM indomethacin , for one5 mMSCs. The chondrogenic medium consisted of high-glucose DMEM supplemented with 500 ng/ml bone morphogenetic protein-2 , 10 ng/ml transforming growth factor β3 , 10-7 M dexamethasone, 50 μg/ml ascorbate-2-phosphate, 40 μg/ml proline, 100 μg/ml pyruvate, 1 × insulin-transferrin-selenium and 1 × lenolenic acid-bovine serum albumin (LA-BSA) (Sigma). The monolayers or pellets were incubated in this medium for 1-2 weeks with medium change twice a week. The monolayers were fixed and stained with Alcian blue. The pellets were embedded in tissue-freezing medium (Leica), sectioned into 8-μm slices, fixed with cold acetone and stained with Alcian blue.Chondrogenic differentiation was performed in 70-80% confluent monolayer or in a pellet  formed b4 each), stained with PE-conjugated antibodies at final concentration of 2 μg/ml at room temperature for 30 min, washed with PBS and analyzed by flow cytometry. For flow cytometry analysis of γ-H2AX, cells were fixed with 3.7% paraformaldehyde, permeabilized with 0.1% Triton X-100 and blocked in 3% normal goat serum (Sigma) in PBS. After incubation with 2 μg/ml anti-γ-H2AX antibody  at 4 °C overnight, the cells were washed and stained with Alexa 488-conjugated goat anti-mouse IgG  for 1 hour, and washed and analyzed as above. Immunostaining of pluipotency-associated markers was performed with following primary antibodies: Oct-4 , Nanog  and SSEA1 , and secondary antibodies: Texas red conjugated anti-mouse IgG  or Alexa fluor 488 goat anti-mouse IgM (Molecular Probes). Immunofluorescence was observed and imaged using a Leica microscope equipped with epi-fluorescence and appropriate filters.For flow cytometry analysis of mMSCs epitope, following PE conjugated antibodies were used: CD31, CD34, Flk-1, Sca-1, CD44 (eBioscience), CD45, CD11b (Miltenyi Biotec). Cells were divided into aliquots  [2DCFDA for 30 min at 37°C. Then the cells were washed, resuspended, and analyzed by flow cytometry. The median fluorescence intensity was used to estimate intracellular ROS levels.Intracellular reactive oxygen species (ROS) was determined by flow cytometry using 5-b-chloromethyl-2'7'-dichlorodihydrofluorescin diacetate (CM-H Probes) ,57. mMSCMicronucleus assay was performed as described with slight modification . Culture3 peptide nucleic acid (PNA) probe  was performed as described [mMSCs at 50-80% confluence were incubated with 0.1 μg/ml colcemid (Sigma) for 5 h. The cells were incubated in hypotonic solution (0.075 M KCl), fixed in methanol/acetic acid (3:1) and spread onto slides. Cell spreads were stained with 5 μg/ml Hoechst 33342 (Molecular Probes) in PBS, examined by immunofluorescence microscope, and number of chromosomes were counted. FISH with FITC-labelled telomere-specific (CCCTAA)escribed .6 mMSCs were subcutaneously injected into 4 weeks old BALB/c nude mice. The animals were monitored for tumor formation for two months. Formed tumors were excised, fixed in formalin, paraffin embedded, sectioned, and stained with hematoxylin and eosin.2 × 104 cells/well into 6-well plates coated with MEF-ECM or gelatin. The mMSCs and TTFs were infected with virus/polybrene-containing supernatant twice within forty eight hours. Three days after infection, the cells were replated in ES medium . The cells were passaged at day 5 onto MEF feeders and the medium was changed every day. ES-like colonies were picked by day 10 to 13, and passaged onto MEF feeders.iPS cells were induced by transduction of four Yamanaka's factors according to the protocol of Okita et al.  with sliAlkaline phosphatase assay was performed using the Vector Blue Aalkaline Phosphatase Substrate Kit  according to manufacturer's instruction.The data were analyzed by Student's t-test. Results are expressed as mean ± SD. A value of p < 0.05 was considered significant by comparison. All experiments were performed at least three times.mMSCs: mouse mesenchymal stem cells; ECM: extracellular matrix; IDmMSCs: immunodepleted mMSCs; PBN: alpha -phenyl-t-butyl nitrone; NAC: N-acetylcysteine; CmMSCs: mMSCs on control plastic; EmMSCs: mMSCs on ECM; PCmMSCs: mMSCs on control plastic in the presence of PBN and NAC; PEmMSCs: mMSCs on ECM in the presence of PBN and NAC. TTFs: tail-tip fibroblasts; iPS cells: induced pluripotent stem cells.FGK conducted the majority of experiments and contributed to drafting the manuscript. WL participated in cell culture experiments and micronucleus assay. LC participated in tumorigenic assay and performed the statistical analysis. LBP participated in karyotype analysis. WF aided in MEF preparation and participated in differentiation experiments. LMS and WF conducted iPS and related experiments. ZLJ provided support and participated in FACS analysis. LL conceived the study and contributed to drafting the manuscript. All authors read and approved the final manuscript.


Background. The etiology of attention-deficit hyperactivity disorder (ADHD) is complex.This study was conducted to evaluate the pregnancy-related maternal risk factors of ADHD. Methods. 164 ADHD children attending to Child and Adolescent Psychiatric Clinics compared with 166 normal children selected in a random-cluster method from primary schools. ADHD rating scale and clinical interview based on Schedule for Affective disorders and Schizophrenia for School-Aged Children (K-SADS) were used to diagnose ADHD cases and to select the control group. Results. The mean maternal age at pregnancy, duration of pregnancy, and the mean paternal age were alike in two groups. The ADHD children's mothers compared with those of control group had higher frequencies of somatic diseases, psychiatric disorders, and alcohol and cigarette exposure during the pregnancies (P < 0.01). Also birth by cesarean section was more common among mothers of ADHD children (P < 0.001). These factors plus trauma to the abdomen during pregnancy were significantly predictors of ADHD in children. Conclusions. Some pregnancy-related maternal factors may be considered as environmental risk factors for ADHD. Each of these factors considered in our study as a risk factor needs to be tested and confirmed through next methodologically appropriate researches in this field. Attention-deficit hyperactivity disorder (ADHD) is one of the most common psychiatric disorders among school-aged children. Reports on the prevalence of ADHD in the United States have varied from 2 to 20 percent of grade-school children . In a stRegarding to the high prevalence of ADHD and its psychosocial outcomes such as social isolation and stigma, negative attributions by the peers, conduct disorder, substance-related disorders, and mood disorders, the importance of preventive and therapeutic interventions is revealed. However, as the etiology of ADHD is complex and most likely includes genetic and environmental factors, preventive and therapeutic interventions may not be sufficient unless we could discover much more factors involved in developing ADHD. Hence, considering the etiological factors with different approaches is something of importance. As it is shown, genetic predisposition is a major cause in ADHD, but it does not follow the Mendelian patterns of inheritance and it is likely to be a polygenetic disorder so that genes can exert their influence only via interaction with the environment. On the other hand, the pathogenetic mechanisms for expression of various genes in interaction with various environmental factors can vary widely from one individual to another . This isA number of nongenetic environmental factors have been shown to be associated with ADHD. Some of these factors include traumatic brain injury , 6, expoReview of the literature shows that some of pregnancy-related factors also may be effective in children's health. Unwanted pregnancy that may be followed with elective abortion may have major negative psychological and physical outcomes. Some studies have reported the association of unwanted pregnancies with neonatal mortality, childhood schizophrenia, and child abuse –14. HoweAmong other factors, also, exposure to cigarette during pregnancy has been shown to be a risk factor for ADHD and conduct disorder –18. It hIn Parent Management Training (PMT) sessions for mothers of ADHD children, held in our department, we were asked different questions about the probable pregnancy-related maternal causes of ADHD. As the literature lacked to give us the definite answers to their questions, so this matter was the main motive for us to design a research to study the probable role of some pregnancy-related events as risk factors for ADHD. Hence, we hypothesized that different pregnancy-related factors or events may be some of contributing factors for ADHD. These factors included: the mean age of parents at pregnancy, duration of pregnancy, recognized somatic disease or psychiatric disorder, cigarette and alcohol exposure, cesarean section, X-ray exposure, trauma to the abdomen , infections, dysentery, bleeding, preeclampsia, unwanted pregnancy, and attempted abortion.This case-control study was performed in 2009. 164 children with ADHD were selected with a nonrandom convenience method from sequential referrals to child and adolescent psychiatric clinics of Tabriz University of Medical Sciences, Iran. Also 166 healthy students were selected as control groups. Regarding the age range of the case group, the control group was selected with a random cluster sampling method from among primary schools' students in Tabriz, Iran. They were recruited from a concurrent epidemiological study done among the primary school's students . There wInclusion criteria for case group were clinical diagnosis of ADHD according to DSM-IV-TR and parental written consent. The children with general somatic diseases and major psychiatric comorbidities were excluded. Inclusion criteria for control group were diagnosis of “no major psychiatric disorders” and parental written consent. The children with general somatic diseases were excluded.The ADHD rating scale includes 18 items that each one shows one ADHD symptom according to DSM-IV-TR criteria. It may be used for age range of five to 18 years and is useful for differentiation of ADHD and healthy children and differentiate attention-deficit symptoms from hyperactivity and impulsivity symptoms. The validity of ADHD rating scale is approved by Dupaul et al., and its reliability is reported to be high . We usedThis is a diagnostic semistructural interview designed according to DSM-III-R and DSM-IV and was filled via an interview with parents and children by a psychiatrist. The reliability of Persian version of K-SADS diagnostic interview was reported to be 0.81 in test-retest method and 0.69 in interrater reliability by Ghanizadeh et al. in Iran . They reP value less than 0.05 was considered statistically significant.The obtained data were analyzed by descriptive methods  and Fisher's exact test. Also for determining the contributing factors for ADHD, the logistic regression analysis was used. Data were analyzed using SPSS (version 17) software , and t-test showed no statistically significant difference between mean parental ages at pregnancy and pregnancy duration in case and control groups.Mean age of the children was 9.2 ± 2.23 years and 9.02 ± 1.53 years, in case and control groups, respectively. According to P < 0.01). Also they gave more birth by cesarean section (P < 0.001). The frequency of trauma to the abdomen, X-ray exposure, infections, dysentery, bleeding, preeclampsia, unwanted pregnancy, and attempted abortion was not significantly differed between the case and control groups.According to P = 0.04), psychiatric disorder (P = 0.008), trauma to the abdomen (P = 0.04), cigarette and alcohol exposure (P = 0.023), and cesarean section (P < 0.001) in mothers were predictors of ADHD in children.The results obtained from binary logistic regression test showed that somatic disease  during pregnancy have a significant association with ADHD and are predictors of ADHD in children. This finding is alike with that reported by Rothen et al. . In geneAccording to our findings, trauma to the abdomen during pregnancy  may be predictive of ADHD in children. In the present study, we considered the general history of trauma during pregnancy and did not differentiate between different types of trauma with different severities. However, it seems that the type and severity of trauma and probable amount of injury are important factors in this regard, as some of studies have emphasized on the association of severe head trauma with ADHD . Our finAnother part of findings in this study showed that frequency of some other pregnancy-related events, that is, unwanted pregnancy, abortion attempt, X-ray exposure, infections, dysentery, bleeding, and preeclampsia has no probable effect on development of ADHD.Although the unwanted pregnancy and subsequently the attempted abortion are public and universal problems effective on women, families, and society , it seemBased on our findings, in general, infections, dysentery, bleeding, and preeclampsia during pregnancy are not risk factors for ADHD; it seems that ADHD is a profound disorder, and the situations in which these factors develop may not have sufficient duration and severity to cause ADHD. Indeed these types of pregnancy-related factors may have different severities, and therapeutic interventions may inhibit real effects of these factors during pregnancy. Nevertheless, some studies have shown that the ADHD children's mothers compared with healthy children's mothers have more viral disease and rash . To concThe present study had some limitations among which the most important one was the nonrandom selection of the case group. This may lead to the likelihood of selection bias in case samples and make limitations regarding the generalizability of the results. On the other hand, as getting the information about pregnancy-related risk factors was mainly based on the history taking from mothers, the recall bias may also affect the results. However, the findings of our study emphasizes on the likelihood of influence of some environmental factors in development of ADHD. Each of these factors considered in our study as a risk factor needs to be tested and confirmed through next methodologically appropriate researches in this field.According to our findings somatic and psychiatric disorders, alcohol and cigarette exposure, trauma to the abdomen during pregnancy and election of cesarean section for labor are some of risk factors for ADHD. However, it is difficult to explain the definite mechanism of effect of these pregnancy-related factors in development of ADHD in children. As mentioned earlier in this paper, genetic predisposition is a major cause in ADHD, but it does not follow the Mendelian patterns of inheritance, and it is likely to be a polygenetic disorder so that genes can exert their influence only via interaction with the environment. Pregnancy-related maternal factors may be considered as some of these environmental factors that exert their influence through interaction with genetic predisposition in the targeted child with ADHD.


Increasing evidence suggests exposure to adverse conditions in intrauterine life may increase the risk of developing attention-deficit/hyperactivity disorder (ADHD) in childhood. High maternal pre-pregnancy body mass index (BMI) has been shown to predict child ADHD symptoms, however the neurocognitive processes underlying this relationship are not known. The aim of the present study was to test the hypothesis that this association is mediated by alterations in child executive function. = 4.80, p = 0.03) and of child performance on the Go/No-go task  = 8.37, p = 0.004) after controlling for key potential confounding variables. A test of the mediation model revealed that the association between higher maternal pre-pregnancy BMI and child ADHD symptoms was mediated by impaired executive function , p = 0.02).A population-based cohort of 174 children (mean age  = 7.3±0.9 (SD) yrs, 55% girls) was evaluated for ADHD symptoms using the Child Behavior Checklist, and for neurocognitive function using the Go/No-go task. This cohort had been followed prospectively from early gestation and birth through infancy and childhood with serial measures of maternal and child prenatal and postnatal factors. Maternal pre-pregnancy BMI was a significant predictor of child ADHD symptoms (FTo the best of our knowledge this is the first study to report that maternal pre-pregnancy BMI-related alterations in child neurocognitive function may mediate its effects on ADHD risk. The finding is clinically significant and may extrapolate to an approximately 2.8-fold increase in the prevalence of ADHD among children of obese compared to those of non-obese mothers. These results add further evidence to the growing awareness that neurodevelopmental disorders such as ADHD may have their foundations very early in life. Attention-deficit/hyperactivity disorder (ADHD) is the most common neurobehavioral disorder of childhood. It is estimated to affect between 5 and 10% of all children, with increasing trends over the past decade in diagnosis and treatment Thus, the aim of the present study was to test the hypothesis that the association between maternal pre-pregnancy BMI and child ADHD symptoms is mediated by deficits in child cognitive function. ADHD symptoms and executive function were assessed in a population-based cohort of children who had been followed prospectively from early gestation. The possible residual confounding effects of maternal characteristics , pregnancy characteristics , and subsequent child characteristics  were adjusted statistically or accounted for by study design (exclusionary criteria).Mean severity of rating of ADHD symptoms (as assessed by the CBCL) could range between 0 and 2. The average score in this population-based  cohort of children was 0.45±0.41 (mean ±SD). No symptoms were reported (score 0) for 19% of the children, the symptom score was between 0 and 1 for 81% of the children, and greater than 1 for 10% of the children. This observed distribution of scores is consistent with expected norms, in that patients diagnosed with ADHD typically have a T score of >60 The average reaction time on the Go/No-Go task was 539.6±87.3 msec (SD), and the average number of correct trials (out of 50) was 39.8±5.5 (SD). On average, more errors were due to false alarms  than to missed trials . The average performance efficiency (reaction time/number of correct responses) was 13.87±3.3 (SD).Severity of ADHD symptoms was significantly correlated with performance efficiency on this task . = 4.80, p = 0.03). Also, group differences in severity of ADHD symptoms based on pre-pregnancy BMI category were observed  = 4.06, p = 0.02; see d effect size  = 0.54 standard deviation (SD) units). Six out of 28 (21.4%) children of obese mothers had a CBCL score >1  = 0.03, p = 0.86).Maternal gestational weight gain was not significantly associated with child ADHD symptoms  = 8.37, p = 0.004). Also, significant differences in child performance on the Go/No-go task were observed based on BMI category  = 3.57, p = 0.03; see d effect size  = 0.62 standard deviation (SD) units).Maternal pre-pregnancy BMI was significantly associated with child performance on the Go/No-go task  = 2.46, p = 0.12, BMI categorical: F = 0.62, p = 0.54) or number of false alarms  = 1.70, p = 0.19, BMI categorical: F = 1.91, p = 0.15). However, there was a significant association between pre-pregnancy BMI and a higher rate of omission errors  = 8.38, p = 0.004, BMI categorical: F = 3.52, p = 0.03). Post-hoc tests revealed that offspring of obese mothers had a higher rate of omission errors than children born to normal weight (p = 0.002) and overweight (p = 0.02) mothers. Offspring of overweight mothers did not differ in the rate of omission errors from offspring of normal weight mothers (p = 0.58).Additional analyses on mean reaction time and types of errors were performed to explore whether the less efficient task performance was due to impulsive behavior or inattention. Maternal pre-pregnancy BMI was not associated with reaction time  = 0.27, p = 0.61).Maternal gestational weight gain was not significantly associated with performance on the Go/No-go task . Second, it has clinical implications, in that it suggests a specific, targeted intervention strategy that can be developed and tested in at-risk children of obese mothers. Executive function may be a malleable trait, particularly during critical postnatal developmental periods when key brain networks that sustain attention processing are developing and are maximally plastic The biological pathways underlying the observed effects in the current study likely relate to inflammation. The state of obesity before and during pregnancy is a major reason for increased systemic inflammation in not only the maternal but also the fetal compartment per se. This, in turn, raises the intriguing possibility that the state of maternal health prior to pregnancy may have a more important bearing on gestational, birth and subsequent child outcomes than events in the index pregnancy. We note a growing body of evidence is beginning to shed light on the mechanisms by which maternal life-course factors may influence birth and child outcomes Consistent with previous reports A recent study in two independent cohorts was not able to replicate the association between maternal pre-pregnancy BMI and child attention problems which led the authors to the conclusion that such previously observed associations were due to residual confounding Another strength of the present study is our use of a population-based, as opposed to a clinical, sample of mother-child dyads, in which the distribution of maternal BMI and other maternal and child characteristics closely resembles that of the general population. Therefore, the results of the current study likely are more generalizable than those from studies encompassing or enriched by individuals with a clinical diagnosis of ADHD .Obesity during pregnancy is increasing worldwide Study participants comprised a cohort of children (mean age 7.3±0.9 (SD) yrs, 55% girls) who had been followed prospectively from early gestation and birth through infancy and childhood. Pregnant mothers were recruited in early gestation from the obstetric care provider clinics at the University of California, Irvine, School of Medicine in Orange, CA, and the Cedars Sinai Medical Center in Los Angeles, CA. Exclusionary criteria at the time of recruitment of pregnant mothers included tobacco, alcohol, or other drug use in pregnancy; uterine or cervical abnormalities; or presence of conditions associated with dysregulated neuroendocrine and immune function such as endocrine, hepatic or renal disorders or corticosteroid medication use. Exclusion criteria for children were preterm delivery <34 weeks gestation, perinatal complications associated with neurological consequences , and congenital, genetic, or neurologic disorders . Moreover, children of underweight women (pre-pregnancy BMI <18.5) were excluded in the current analysis because maternal under-nutrition also has been shown to alter the offspring’s neurodevelopmental trajectory 2) was computed based on pre-pregnancy weight abstracted from medical charts and maternal height measured at the research laboratory during the first visit. Pre-pregnancy BMI was treated both as a continuous and categorical variable. Based on pre-pregnancy BMI, mothers were either classified as normal weight (BMI: 18.5–24.99), overweight (BMI: 25–29.99) or obese (BMI ≥30) in accordance with the Institute of Medicine (2009) recommendations Maternal pre-pregnancy BMI , 19 (n = 172), 25 (n = 170), 31 (n = 170) and 37 (n = 142) weeks gestation. Since maternal and fetal weight gain flatten after week 37 Obstetric risk was defined as the presence of major medical complications in the index pregnancy, i.e., gestational diabetes, vaginal bleeding, placenta abruptio, pregnancy-induced hypertension, preeclampsia, or infection. Risk conditions were ascertained by extensive medical chart review and coded as a binary variable (presence or absence of obstetric risk), as previously described Gestational age was determined by best obstetric estimate with a combination of last menstrual period and early uterine size, and was confirmed by obstetric ultrasonographic biometry before 20 weeks using standard clinical criteria Birth outcomes were abstracted from medical charts after delivery, and birth weight percentiles were computed using national norms At the first visit during pregnancy, standardized structured interviews were conducted for ascertainment of maternal sociodemographic characteristics .Child ADHD symptoms were assessed using the Child Behavior Checklist (CBCL) Child executive function was assessed using an objective Continuous Performance Task (Go/No-go task) that required the execution of an anticipated motor response or its active inhibition. The Go/No-go task is a widely used task for assessment of neurocognitive impairment in ADHD patients Mothers were administered the Perceptual Reasoning Index (PRI) of the WAIS-IV Maternal depressive symptoms at the time of the child assessment were assessed using the Beck Depression Inventory A history of either maternal or paternal ADHD was abstracted from available standard family mental health interviews. For six of the children in the study either the mother or father or both had an ADHD diagnosis . Five of these children were offspring of normal-weight mothers, and one child was born to a mother who was overweight before she became pregnant. Although these 6 children may carry a greater genetic susceptibility for ADHD, because 5 of these 6 children were born to mothers who were normal pre-pregnancy weight, these cases were not excluded from the study sample, however, all the statistical analyses were repeated excluding these cases to determine whether they altered any of the results.vs overweight vs obese). Post-hoc analyses using the Least Significant Difference (LSD) test were performed to examine the effects of specific BMI group differences.Univariate ANOVAs were conducted to examine the associations between maternal pre-pregnancy BMI, maternal gestational weight gain, child ADHD symptoms and child executive function, adjusting for the following potential confounding variables: pregnancy characteristics and birth outcomes , child characteristics , and maternal characteristics . Maternal pre-pregnancy BMI was included in the statistical models as both a continuous variable  as well as a categorical variable  was computed in order to place effects expressed in the original raw units of measurement ) in the more generic and dimensionless context of standard deviation (SD) units Next, for statistically significant effects between pre-pregnancy BMI groups, a standardized effect size (Cohen’s Finally, regression analyses were performed to test for the potential mediating effect of impaired executive function following the criteria outlined by Barron and Kenny


This study was a retrospective chart review performed to examine and describe physician practice patterns in managing attention deficit/hyperactivity disorder (ADHD) across Europe. Physicians treating ADHD in the UK, France, Germany, Italy, the Netherlands and Spain were recruited. Each physician abstracted medical records of five patients (aged 6–17 years at time of review) with a documented diagnosis of ADHD made between January 2004 and June 2007. Data provided by the physician via the abstraction included (a) physician characteristics, (b) patient characteristics, (c) ADHD diagnosis and (d) ADHD outcomes . A total of 779 patients met study inclusion criteria. In the overall population, patients’ mean (SD) age at time of diagnosis was 8.9 (2.6) years. The predominant treatment choice was long-acting methylphenidate, which was prescribed to more than 56 % of patients. According to physicians, only 30.8 % of patients showed ‘complete symptom control’ on current treatment and only 31.8 % of physicians reported being ‘very satisfied’ with their patients’ current treatment. Physicians’ assessments of complete symptom control and physician satisfaction with treatment were low, indicating unmet needs with current ADHD management in Europe. Attention deficit/hyperactivity disorder (ADHD) affects as many as 3 to 9 % of children worldwide , 19 and According to European guidelines, the diagnosis and management of ADHD consists of nonpharmacological options, including behavioural therapy (BT), and pharmacological options, including stimulants (long- and short-acting methylphenidates and amphetamines) and nonstimulants , 24. HowThis study was designed as a retrospective review of patient medical records by their treating physicians Fig. . In 2009Physicians were contacted by either email or phone calls to assess physician eligibility and interest in participating in the study. If eligible physicians indicated interest, they were directed to complete a web-based screening questionnaire. Physicians were screened as eligible for inclusion in the study if they were engaged in clinical practice for between 3 and 30 years, managed the treatment of at least five ADHD patients (aged 6–17 years) per month and were responsible for making ADHD treatment decisions.Physicians were required to identify the most recent ADHD patients (up to a maximum of five patients aged 6–17 years) that they had seen at the time of the review. In order for patients to be included in the study, they should have had a documented diagnosis of ADHD between January 2004 and June 2007 and have had at least 2 years of follow-up post-diagnosis. Patients were also required to have received either pharmacological treatment or BT following the ADHD diagnosis. Patient charts were excluded if there was evidence of enrolment in a randomized clinical trial. No other specific sampling strategies were employed.Physicians abstracted patient chart data, entered the data into an electronic web-based form and then translated it into the local language. Instructions for completing the chart abstraction were provided on the web-based form. The data collection tool was designed in such a way that physicians were not able to skip any questions; however, if certain information was not available in the patients’ chart, physicians could select a ‘don’t know’ option. Wording for key questions regarding satisfaction, symptom control and adherence to the treatment regimen has been included in the Both physician characteristics and patient characteristics were collected. The following patient characteristics were collected from the chart: age at diagnosis and at start of treatment, gender, ethnicity, insurance status, education level, reasons for seeking evaluation, comorbidities at diagnosis and the level of patient engagement and family involvement with the condition and its treatment on a ten-point scale where 1 represents ‘not engaged/involved at all’ and 10 represents ‘strongly engaged/involved’. Other ADHD-related information collected included ADHD diagnostic criteria utilized, ADHD treatment goals, ADHD symptom presentation and levels of impairment at the time of ADHD diagnosis on a ten-point scale where 1 represented ‘no impairment’ and 10 represented ‘high level of impairment’ (from 2004 to 2007). Also, treatment modalities were collected starting from the time of chart abstraction and going backwards up to five previous ADHD treatments. Data collected on treatment modalities included dose, prescription date and reason for changing dose and/or therapy. A switch from one treatment modality to another or a discontinuation of treatment was considered as new treatment. Dose changes for the same medication were not considered as new treatment. Data on treatments administered in other clinics or those that exceeded the last five treatments were not documented.Data on adherence to current and previous ADHD treatments were also collected. Physicians were asked to report on the patient’s ADHD symptom control  and their satisfaction level  with treatment at time of chart abstraction.Associations between patient characteristics and outcomes were examined using a binary outcome definition for adherence, physician perception of symptom control and physician satisfaction  to simplify the analysis and its interpretation. Physician-estimated adherence to treatment was defined as >80 % adherence during weekdays and >50 % adherence during weekends and holidays in accordance with the literature characterizing the medication possession ratio  and its All study variables were summarized descriptively. Continuous variables were summarized and expressed in mean values, medians, ranges and standard deviations. Categorical variables were summarized in the form of proportion and frequency distributions. Summary statistics are provided by country for physician, patient and treatment characteristics and for diagnosis criteria used.p < 0.05) of the associations was tested using Fisher’s exact or t-tests for dichotomous and continuous variables, respectively. Odds ratios were reported for dichotomous values and mean values were reported for continuous variables.The significance .A total of 340 physicians reviewed and abstracted charts for 779 patients. On average, physicians were engaged in clinical practice for 15 years (range 3 to 30 years). Each physician managed approximately 20 patients aged 6 to 12 years and 15 patients aged 13 to 17 years. Medical specialties are listed in Table Patient demographics are presented in Table Feedback from teachers at school was the most common reason for seeking ADHD evaluations (78.3 % [610/779]) across all countries. Challenges raised by parents/family were also a common reason for seeking evaluation among 63.8 % (497/779).Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) (55.7 % [434/779]), and International Classification of Diseases, Revision 9 or 10 (ICD-9/ICD-10) (46.3 % [361/779]). ADHD Connors Test (49.4 % [385/779]) was also commonly used, though physicians may have used more than one set of diagnostic criteria to make an ADHD diagnosis. As presented in Table Across all countries, the commonly used diagnostic criteria included the The most common symptoms at diagnosis were the core symptoms of ADHD  as well as impairments with school performance Fig. . ApproxiAt diagnosis, most physicians across all six countries indicated (based on the provided choices) that a goal of ADHD treatment was to improve attention and functioning at school or work for their patients  were on their first ADHD treatment regimen (either drug or nondrug), 37.9 % (295/779) had one previous line of therapy and the remaining 12.6 % (98/779) of patients received two or more previous lines of therapy  were treated with a combination of pharmacotherapy and BT, whereas 48.0 % (374/779) of patients were undergoing treatment with pharmacotherapy only and 11.6 % (90/779) with BT only  either as monotherapy or in combination. Overall, short-acting methylphenidates (25.1 % of patients) and atomoxetine (13.5 % of patients) were the next most commonly used treatments . Adherence was estimated to be highest in patients receiving combination medication therapy (80.0 %) and lowest for patients receiving BT only (12.2 %). However, according to physician judgement, only 30.8 % of patients showed ‘complete symptom control’. Symptom control was highest for patients receiving long-acting methylphenidate (36.2 %) and lowest for patients receiving BT only (15.6 %). Only 31.8 % of physicians were ‘very satisfied’ with their patients’ ADHD treatment at the time of chart abstraction. Highest physician satisfaction was reported for patients receiving medication combination therapy (38.8 %) and lowest satisfaction was reported for patients receiving BT only (14.4 %).p < 0.0001; Table Generally, we found positive associations between the need to improve inattention as a treatment goal at diagnosis, increased patient engagement and increased family involvement and all three outcomes . The odds of a favourable outcome for patients with improving inattention as a treatment goal were approximately twofold higher than for those patients for whom improving inattention was not a stated goal  and 3.3-fold , respectively. Patients perceived to have complete symptom control had a mean number of 2.2 comorbidities compared to a mean number of 3.0 comorbidities in those patients without complete symptom control  were negatively associated with outcomes. For instance, in patients with comorbid Tourette syndrome, the odds of favourable symptom control and physician satisfaction were reduced fivefold . Furthermore, as seen in Table p < 0.0001).The presence of certain ADHD symptoms at the time of diagnosis was also associated with unfavourable outcomes. The odds of favourable physician satisfaction with ADHD treatment was reduced 1.7-fold in patients with the symptom of anger at the time of diagnosis , Italy (70.1 % [101/144]), the Netherlands (81.1 % [60/74]) and Spain (79.1 % [106/134]). ADHD Connors Test was frequently part of the diagnostic assessment in the UK (69.2 % [101/146]). ICD-9/ICD-10 diagnostic criteria were most commonly used in Germany (87.4 % [132/151]).Country level variation in the treatment of ADHD was also noted. The UK had the highest rate of treatment with pharmacotherapy alone at 63.7 % (93/146). Treatment with BT alone was most common in Italy (41 % [59/144]) and least common in the UK (<1 % [1/146]). More than 54 % of patients in Italy used short-acting methylphenidates, while Spain did not report any use at all. Atomoxetine was most commonly used in Italy (36.7 %), but it was not available in France because it has not been approved by the Comité Economique des Produits de Santé. Short-acting amphetamines were not used in France or Spain and were used by less than 2 % of patients in Germany, the UK and the Netherlands. The highest use for short-acting amphetamines is in Italy (9 %) (Table The percentage of patients who adhered to their ADHD treatment ranged from 50.8 % (62/122) in Italy to 80.3 % (94/117) in France. Physicians from the Netherlands reported the highest percentages of ‘complete symptom control’ (52.8 % [38/72]), while Italian physicians reported the lowest percentage (16.4 % [22/134]). Methylphenidate ‘very good responders’ ranged from 11.1 % (16/144) in Italy to 35.1 % (53/151) in Germany. Physicians in Germany (46.0 % [63/137]) and the Netherlands (59.7 % [43/72]) reported the highest percentages of ‘very satisfied’, while physicians in Italy reported the lowest percentage (14.8 % [20/135]).Country-level variations were evident in patient characteristics as well as ADHD diagnosis, treatment and outcomes. Patients had differences in comorbidities at the time of ADHD diagnosis across countries. Therefore, it is important that all treating physicians have a similar knowledge and understanding not only of the diagnosis and management of ADHD but also the associated comorbid conditions to deliver optimal treatment based on individual patient needs and a global view of the problems. Evaluations of differences in treatment based on patient comorbidities are planned for future analyses.Patients also had differences in private insurance membership based on country. In the Netherlands, all patients were members of private insurance, but in the UK, where ADHD treatment is free under the National Health Service, only 2.7 % had private insurance. The discrepancies in membership to private insurance across countries may influence ADHD management and treatment decisions for patients. Future analyses are planned to better understand ADHD management differences within countries and specialties as well as differences in treatment based on comorbidities.Within each country, the criteria used to diagnose ADHD varied by physician specialty as well. The criteria provided in DSM-IV were the most commonly used to diagnose ADHD in the countries studied. Use of the Swanson, Nolan and Pelham IV Rating Scale (SNAP) and the Inattention/Overactivity With Aggression (IOWA) screening tool increased each year from 2004 to 2007. Although scales like SNAP and IOWA are valuable for screening patients for ADHD, if used alone, they may lead to overdiagnosis or misdiagnosis. Adoption of standardized diagnostic criteria across countries may address some of the variability noted worldwide in ADHD prevalence , 19. ADHAt ADHD diagnosis, physicians regarded core ADHD symptom control as a primary therapeutic goal. In the short term, controlling core symptoms is of key importance as hyperactivity, impulsivity and inattention frequently create dysfunction for patients, their families and their peers. However, it is important to note that ADHD treatment is not limited to symptom control only. Treatment goals must also include longer-term objectives such as improving the quality of life for both the patient and their families and reducing functional impairment for the patient .In this study of ADHD treatment in European countries, more than half of patients received long-acting methylphenidate as the treatment of choice, except in Italy where it was not approved and therefore short-acting methylphenidates were the treatment of choice. This may also account for a higher rate of BT only and a lower rate of treatment response and treatment satisfaction in Italy compared with other countries. Whether or not BT was available through national health plans and consideration of waiting times may have affected these numbers. In addition, differing recommendations from the various physician specialties and other variations in availability of medication may have also influenced these data. The rationale behind the choices of ADHD treatments  is planned for further analysis.Overall, across all of the countries studied, patients with ADHD were considered by physicians to have high rates of adherence  with treatment on school or working days. However, less than one third of the patients were perceived by their physicians to exhibit ‘complete symptom control’ and less than one third of physicians were ‘very satisfied’ with the current ADHD treatment for their patients. The low overall percentages and high country variability for ‘complete symptom control’ and ‘very satisfied’ may be indicative of cultural differences among countries in the acceptability of physicians indicating dissatisfaction with ADHD therapy or as a result of inconsistency among countries in shared decision-making between physicians and patients/caregivers. We observed that patient/family involvement in the disorder and its treatment was positively associated with adherence, symptom control and physician satisfaction with treatment, reflecting the influence on treatment outcomes of shared decision-making . In addip-values presented in the results should be considered descriptive. However, given the fact that this is the first work that attempted to study real-world practice variation and management of ADHD across European countries, the evidence generated in this research still provides valuable additional information to the body of literature in ADHD.This study was a retrospective chart review with inherent study design limitations, including the potential for incomplete or missing documentation as well as the inability to establish causality. The potential for selection bias in this study should be considered due to the convenience sampling strategy implemented. It is not known whether a greater number of physicians participated from secondary referral centres compared with those from primary care settings; thus, it is not possible to determine whether an oversampling of charts from more complex or difficult patients occurred in this study. Confounding factors included the variable availability of ADHD treatments, including BT, across countries and the lack of information regarding whether a patient started initial ADHD therapy in a clinic that was different from the clinic where the actual medical record abstraction occurred. Because this was an observational study of a convenience sample where patient charts were not sampled randomly, the generalizability of these study results to the entire European population may be limited. Furthermore, this study was conducted for descriptive and exploratory purposes and was not designed for testing of particular statistical hypotheses. As such, ADHD management differs across European countries and across physician specialties. Variations in patient characteristics as well as ADHD diagnosis, treatment and outcomes were evident between countries. Although a high proportion of patients were reported to be adherent to currently available therapy in Europe, less than one third of physicians perceived patients as having complete ADHD symptom control and less than one third of physicians were satisfied with ADHD treatments for their patients. These results suggest that European patients may benefit from better standardization of ADHD management across countries and additional treatment options.