Little is known about the impact of cognitive impairments on driving in adults with ADHD. The present study compared the performance of adults with and without ADHD in a driving simulator on two different routes: an urban route which we hypothesised would exacerbate weak impulse control in ADHD and a motorway route, to challenge deficits in sustained attention.n = 22, 16 males) and without  ADHD completed a simulated driving session while eye movement data were recorded simultaneously. Participants also completed the Manchester Driving Behaviour Questionnaire (DBQ) and the Conners Adult ADHD Rating Scale (CAARS). Measures of driving performance included average speed, proportion distance travelled over speed limit (speeding) and lane deviation. These variables and the eye movement measures  were compared between groups and routes. Also, driving behaviours, including responses to programmed events, were categorised and the frequencies within categories were compared between groups. Finally, speech analysis was performed to compare emotional verbal expressions during driving between groups.Adults with  and a trend for less safe driving when changing lanes/overtaking on the motorway. These effects were predicted by hyperactive/impulsive CAARS scores. They were also more likely to cause a crash/near miss when an event occurred on the urban route.The results suggest that difficulty regulating and controlling impulsive behavior, reflected in speeding, frustration with other road users, less safety when changing lanes on the motorway and a greater likelihood of an accident following an unexpected event, underlie impaired driving in ADHD. Hyperactivity/impulsivity symptoms correlated with these indices. Deficits in sustained attention seemed to play a lesser role in this particular study, although further research is needed to determine whether effects on attention emerge over longer periods of time and/or are influenced by the novelty of the simulator environment. Attention deficit hyperactivity disorder (ADHD) commonly persists into adulthood with prevalence in adult community samples recently estimated at 2.5 % . The cogSignificantly increased rates of driving accidents (including those for which the driver was liable) and driving prosecutions have been reported in adults diagnosed with ADHD (reviewed in –5). ThesIt is known that cognitive impairments in ADHD are reduced by contextual factors that increase motivation  and worsThe present study compared the performance of adults with and without ADHD in a driving simulator in which two different routes were presented: urban and motorway. We chose to use a driving simulator as this enhances the realism of the driving experience compared with studies using a standard computer assessment. Each driving route contained specific events occurring at pre-determined times. Performance indicators including speed, proportion of distance over the speed limit and lane deviation were compared between groups and routes. Considering the influence of motivational incentives on parameters of attention and impulse control in ADHD , 14, 23 As well as standard measures of driving performance, eye movements provide an index of the allocation of visual attention with millisecond precision and tend to be atypical in ADHD . In drivN = 29, 12 females) were patients undergoing assessment or receiving care from the Adult ADHD Clinic, Nottinghamshire Healthcare NHS Trust, U.K. Of 74 potential participants initially contacted about the study, 21 did not drive, 18 were not interested or did not feel able to take part, 1 was outside the age criteria (18 to 55 years) and 5 withdrew after initially agreeing to take part, providing a sample of 29. Participants in the ADHD group had a confirmed lifetime and current diagnosis of ADHD according to DSM-IV-TR criteria. All were recruited through an adult ADHD service led by a Consultant Child & Adolescent Psychiatrist (CH) with extensive experience of assessment and diagnosis of ADHD across the lifespan. Diagnosis was made as part of thorough clinical assessment prior to referring patients for participation in the study. Current and lifetime ADHD diagnosis was established by conducting the Diagnostic Interview for ADHD in Adults (DIVA 2.0 [Sixty-four participants aged 18 to 54 years with a UK driving licence were recruited to this study. Participants in the ADHD group (DIVA 2.0 ), childhDIVA 2.0  and AutiDIVA 2.0 . All parOf the 29 participants with ADHD, 17 were taking stimulant medication, two were taking non-stimulant medication (atomoxetine), one was taking bupropion and nine were not taking any medication. The study was approved by the Nottingham Research Ethics Committee and by the Research & Development department of Nottinghamshire Healthcare Trust. All participants provided fully informed consent.N = 35, 11 females) were recruited through posters displayed on the University of Nottingham campus, U.K. and in local community centres. Volunteers were eligible to take part if they were aged 18 to 55 years, held a driving licence and had never received a diagnosis of ADHD or autism spectrum disorder (ASD).Control participants (All participants completed the CAARS (self-report)  to assesThe driving simulator used was the Nottingham Integrated Transport and Environment Simulation facility’s high fidelity system (NITES 1). This driving simulator consists of a fully instrumented BMW Mini housed within a 360° projection dome mounted on a Bosch Rexroth six degrees-of-freedom motion platform. The wing mirrors of the vehicle contain LCD screens with a graphical representation of the rear view and a sound system provides realistic vehicle and traffic noise.The driving scenario consisted of three different road types. The scenario started in a built-up urban area, which required constant shifting of attention and monitoring and evaluation of performance. After driving 2.1 miles in the urban area, participants reached a single carriageway, which they drove on for 4.6 miles until they reached a three lane motorway which was followed for 9.8 miles. The motorway section contained little traffic, therefore providing a monotonous and low stimulation environment. The single carriageway section was included only to improve the realism of driving from the urban area onto a motorway. All three parts of the drive contained short sections with a speed limit that was lower than the default speed limit for that road type (i.e. 20 mph in the urban area and 40 mph on the carriageway and the motorway). Along the route, five events were programmed to occur, three in the urban area and two on the motorway. Examples of these are pedestrians stepping onto the road and a car suddenly pulling out in the urban area and sudden slowing down of traffic due to an accident on the motorway. Continuous driving performance measures obtained from the simulator were average speed, the proportion of the distance travelled in excess of the speed limit (in excess of 10 % of the speed limit for that road section plus two miles), the coefficient of variation of velocity and the standard deviation of lateral position.Eye movements were recorded simultaneously by two Seeing Machines FaceLAB 5 eye tracking systems using four cameras. Measures obtained were mean fixation duration and the standard deviation of gaze coordinates (spread of search) for both the horizontal and vertical axes.The Manchester Driving Behaviour Questionnaire (DBQ) , one of To obtain a more detailed indication of participants’ driving behaviour, a coding scheme consisting of 23 items in seven categories was developed to score driving errors and violations  text analysis software . This soAll participants in the ADHD group who were on stimulant medication withdrew from medication for 24–36 h (depending on their medication regime) before the study simulator session. Before taking part in the study, participants were asked to fill in an informed consent sheet, a driving and health questionnaire, the CAARS (self-report), AQ and DBQ. After filling out the forms, participants were seated in the simulator and were given instructions about its use and safety procedures. Following calibration of the eye trackers a 5-min practice drive was completed with the experimenter present in the dome. Automated verbal directions were given throughout the route. After completion of this drive, participants completed the 16-item Kennedy Simulator Sickness checklist Questionnaire (SSQ)  to ensurScores on each factor of the DBQ  and items assessing driving history were compared between ADHD and control groups using independent-samples t-tests.The continuous driving performance measures  and the eye movement measures  for both the horizontal and vertical axes) were each entered into separate mixed design ANOVAs. Each ANOVA was designed to assess the between-subject effect of Group  and the within-subject effect of Road Type  on these variables, and the Group*Road Type interaction.The categories identified from the observational coding of driving behaviours were compared between groups by first computing the total frequency of each behaviour within each category and then comparing the group mean frequencies using multivariate ANOVA across items within each category.To compare the type of response to urban and motorway events between groups, the chi-square statistic was computed to determine whether there were group differences in allocation of participants to categories.The frequencies of each category of verbal responses measured using the LIWC software was compared between groups using univariate ANOVAs.In all analyses the threshold for significance was .05 two-tailed. Where group differences are reported, secondary analyses were performed to examine correlations between the dependent variable and scores on the hyperactivity/impulsivity and inattentiveness sub-scales of the CAARS in the ADHD group, computing Pearson’s r or Spearman’s rho depending on the data type. These analyses were performed to determine whether each aspect of impaired driving was explained by variability in hyperactivity-impulsivity or inattention symptoms or both.n = 2) were not withdrawn from medication for the study. To ensure this did not influence the findings, all analyses were re-run excluding these participants. The findings remained the same and the participants were not group outliers (defined as >2.5 SD from the group mean) on any measure. The results are therefore reported with these participants included.Participants on atomoxetine  were unable to complete the entire driving assessment due to simulator sickness. Data for 2 participants (1 ADHD and 1 control) were lost due to technical problems, leaving 22 participants in the ADHD group  and 21 participants in the control group  for analysis. For 2 participants no eye tracking data was available due to recording difficulties. The groups did not differ in age or gender distribution, and scores on the CAARS confirmed significant differences in ADHD symptoms between the groups (see Table p < .001) and the rate of serious accidents . Inattentive symptoms correlated significantly with Violations  and Lapses .Group data for the DBQ and driving history are shown in Table p < .05) and inattentive  scores on the CAARS.A mixed design ANOVA (2 Groups × 2 Road Types) showed significant group differences in the proportion of distance travelled over the speed limit with the ADHD group speeding more than the control group (main effect Group) and more speeding on the motorway than in the urban area (main effect Road Type), but no Group by Road Type interaction  = 1.04, p = .31) or the test drive  = .04, p = .85).There was no difference in reported total simulator sickness symptoms between the ADHD group and the control group either after the practice drive (p < .05) and Changing Lanes/Overtaking on the Motorway . CAARS Inattention scores correlated significantly with Vehicle Control  but not Frustration/Anger or Changing Lanes/Overtaking on the Motorway (p > .05).The analysis of the coded observations of driving behaviour showed poorer performance in ADHD than controls on a number of measures. To reduce the number of comparisons, multivariate analyses were conducted on categories of items, shown in Table F  = 8.44, p < .01. Responses to events on the motorway did not differ significantly between groups.As shown in Table p < .001; Swearing: rho = .46, p < .01). Correlations with CAARS Inattentive scores were non-significant (p > .05).ADHD participants made significantly more comments than controls and the comments made contained more words  or eye movements or fixation duration, differently from control subjects. Furthermore, ADHD participants were as likely as control participants to slow down on the motorway in response to traffic slowing ahead or a change in the speed limit. These results suggests that adults with ADHD can adjust and maintain speed appropriate to the driving environment and can orient attention and maintain focus on the road ahead when driving in a low stimulation driving environment for short periods of time 15 min). Previous studies have reported worse driving in ADHD subjects on a highway (motorway) than an urban route  and in t min. PreAlthough able to respond well to events in the motorway section of the simulated drive, the ADHD group were less likely to change lanes and overtake safely on the motorway, often speeding when overtaking and failing to signal or use mirrors when changing lane. This is consistent with the greater average speed of the ADHD group across both the urban and motorway routes and the tendency to express frustration and anger with other road users, all of which indicate an impulsive driving style, consistent with evidence of impairment in behavioural and emotional self-regulation in ADHD , 26, 42.A number of studies have proposed inattention to be the main or most likely cause of accidents in healthy individuals  and thosFuture studies should examine the impact of stimulant and non-stimulant medications on driving performance in ADHD and the degree to which any improvements following medication administration are related to reductions in hyperactivity/impulsivity and/or inattention symptoms. Although previous studies have reported improvements in a range of indices of driving performance following medication administration (e.g. –45, noneLimitations of the present study include the sample size and composition. Previous studies have shown group differences in MBDQ errors as well as violations and lapses  suggestiThis study examined driving performance in adults with ADHD during a simulated driving session. The ADHD group differed significantly from the typical adult control group on a number of measures, particularly those relating to the expression of frustration and anger during driving. Other differences included vehicle control and average speed as well as speed when overtaking on the motorway. The pattern of effects suggests that, in this sample, impaired driving may be related to problems with the control of emotions and motor actions, rather than inattention, although further research using other measures of attention is needed to determine whether this effect is reliable, and/or influenced by the simulator environment.


Dear Editor,Attention deficit hyperactivity disorder (ADHD), is a common, highly heritable childhood-onset psychiatric disorder affecting 2% – 6% of children worldwide. The recent paper examines the effects of child and adult ADHD symptoms in adults among male students on adult addiction acknowledgment and alcoholism potential . This arIn short, the current results not only support previous studies about the relationship between ADHD and alcohol and drug dependence but also provide further evidence on prediction of future substance dependence in adulthood through early ADHD . However


Pyrethroid pesticides cause abnormalities in the dopamine system and produce an ADHD phenotype in animal models, with effects accentuated in males versus females. However, data regarding behavioral effects of pyrethroid exposure in children is limited. We examined the association between pyrethroid pesticide exposure and ADHD in a nationally representative sample of US children, and tested whether this association differs by sex.Data are from 8–15 year old participants (N = 687) in the 2001–2002 National Health and Nutrition Examination Survey. Exposure was assessed using concurrent urinary levels of the pyrethroid metabolite 3-phenoxybenzoic acid (3-PBA). ADHD was defined by either meeting Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition criteria on the Diagnostic Interview Schedule for Children (DISC) or caregiver report of a prior diagnosis. ADHD symptom counts were determined via the DISC. Multivariable logistic regression examined the link between pyrethroid exposure and ADHD, and poisson regression investigated the link between exposure and ADHD symptom counts.Children with urinary 3-PBA above the limit of detection (LOD) were twice as likely to have ADHD compared with those below the LOD . Hyperactive-impulsive symptoms increased by 50 % for every 10-fold increase in 3-PBA levels ; effects on inattention were not significant. We observed possible sex-specific effects: pyrethroid biomarkers were associated with increased odds of an ADHD diagnosis and number of ADHD symptoms for boys but not girls.We found an association between increasing pyrethroid pesticide exposure and ADHD which may be stronger for hyperactive-impulsive symptoms compared to inattention and in boys compared to girls. Given the growing use of pyrethroid pesticides, these results may be of considerable public health import.The online version of this article (doi:10.1186/s12940-015-0030-y) contains supplementary material, which is available to authorized users. Attention Deficit Hyperactivity Disorder (ADHD), the most common neurobehavioral disorder in children , 2, is aAlthough pyrethroid pesticides are often considered a “safer” choice because they are generally not as acutely toxic as organophosphates , animal et al. found that postnatal pyrethroid exposure was associated with general behavioral difficulties  were tabulated for those who had urinary 3-PBA levels below and above the limit of detection.This study was determined to be exempt from review by the institutional review board (IRB) at Cincinnati Children’s Hospital Medical Center (Study 10-transformed due to skewed distributions) and ADHD, adjusting for potential confounders. To examine the consistency of pyrethroid pesticide associations, additional analyses, available in Additional file The association between ADHD and urinary 3-PBA (levels below versus above the limit of detection) was analyzed via logistic regression, adjusting for potential confounders. Logistic regression was used to examine the association between continuous urinary 3-PBA levels (log10-transformed levels). For each model, adjusted count ratios were calculated to determine the mean percent increase in symptom counts beyond that of the reference group for each stratum of the 3-PBA variables.We used Poisson regression to assess the relationship between urinary 3-PBA levels and the number of inattentive and hyperactive symptoms endorsed as being present ‘often’ in at least two settings, adjusting for potential confounders. The Poisson distribution accounts for the skewed and count nature of these data. Analyses investigated urinary 3-PBA levels as both a dichotomous predictor (levels below versus above the limit of detection) and a continuous predictor , adjusting for potential confounders. Analyses using restricted cubic polynomial splines provide flexibility in modeling the relationship between the exposure and the outcome, and avoid assumptions about model linearity ). Of note, we had reduced statistical power to detect sex*pyrethroid interactions in dichotomous models due to relatively small numbers of participants having the ADHD diagnosis. This pattern suggesting possible sex-specific effects is consistent with prior animal studies that reported greater impulsive and hyperactive symptoms in exposed male but not female mice [et al. found a stronger adverse association between pyrethroid exposure and a measure of total behavioral difficulties as well as oppositional/conduct-specific problems in girls compared to boys [et al. did not find any significant interactions  between sex and pyrethroid exposure, and it is not clear if they observed any patterns suggesting possible sex-specific effects despite the failure to meet thresholds for statistical significance. Certainly, further study of sex-specific vulnerability to pyrethroid exposure is warranted, given mounting evidence that the adverse effects of some ADHD risk factors may be accentuated or limited to certain groups [We observed sex-specific effects of pyrethroid exposure. Urinary pyrethroid biomarkers were associated with increased odds of an ADHD diagnosis and number of ADHD symptoms for boys but not girls in logistic and poisson regression as well as spline analyses. The sex*pyrethroid interaction had a borderline significant p-value of 0.09 when 3-PBA was modeled as a logarithmically-transformed continuous variable. In contrast, the interaction was not statistically significant  and later development of ADHD, as data from animal studies suggest that both the prenatal and postnatal periods may represent susceptible phases for pyrethroid neurotoxicity [An additional limitation of our study is that pyrethroid exposure was assessed using 3-PBA concentrations in a single spot urine sample. Given that pyrethroids are non-persistent and rapidly metabolized, serial measurements would provide a more accurate measurement of typical exposure , and areociation , 43. Subtoxicity –23. AnotMisclassification of ADHD may also have played a role in analyses for which case ascertainment included caregiver report of the child’s prior diagnosis of ADHD, as we cannot verify that doctors in community-based settings used DSM-IV criteria when establishing ADHD diagnoses . HoweverOur results suggest an association between childhood urinary pyrethroid pesticide biomarkers and ADHD, particularly hyperactive-impulsive symptoms, and these associations may be stronger in boys than girls. Given the growing use of pyrethroid pesticides and the perception that they represent a safer pesticide alternative, these results may be of considerable public health importance. However, replication of findings is warranted in prospective, longitudinal studies with serial measurements of pyrethroid pesticide exposure.


Attention-Deficit-Hyperactivity-Disorder (ADHD) is, with a prevalence of 5 %, a highly common childhood disorder, and has severe impact on the lives of youngsters and their families. Medication is often the treatment of choice, as it currently is most effective. However, medication has only short-term effects, treatment adherence is often low and most importantly; medication has serious side effects. Therefore, there is a need for other interventions for youngsters with ADHD. Mindfulness training is emerging as a potentially effective training for children and adolescents with ADHD. The aim of this study is to compare the (cost) effectiveness of mindfulness training to the (cost) effectiveness of methylphenidate in children with ADHD on measures of attention and hyperactivity/impulsivity.A multicenter randomized controlled trial with 2 follow-up measurements will be used to measure the effects of mindfulness training versus the effects of methylphenidate. Participants will be youngsters (aged 9 to 18) of both sexes diagnosed with ADHD, referred to urban and rural mental healthcare centers. We aim to include 120 families. The mindfulness training, using the MYmind protocol, will be conducted in small groups, and consists of 8 weekly 1.5-h sessions. Youngsters learn to focus and enhance their attention, awareness, and self-control by doing mindfulness exercises. Parents will follow a parallel mindful parenting training in which they learn to be fully present in the here and now with their child in a non-judgmental way, to take care of themselves, and to respond rather than react to difficult behavior of their child. Short-acting methylphenidate will be administered individually and monitored by a child psychiatrist. Assessments will take place at pre-test, post-test, and at follow-up 1 and 2 (respectively 4 and 10 months after the start of treatment). Informants are parents, children, teachers, and researchers.This study will inform mental health care professionals and health insurance companies about the clinical and cost effectiveness of mindfulness training for children and adolescents with ADHD and their parents compared to the effectiveness of methylphenidate. Limitations and several types of bias that are anticipated for this study are discussed.NTR4206. Registered 11 October 2013. Dutch Trial Register:  Attention-Deficit-Hyperactivity-Disorder (ADHD) is one of the most common childhood disorders, with a prevalence of 5 % . ChildreIt has been demonstrated that children and adolescents diagnosed with ADHD have a substantial economical impact on society –5. A metMedication and psychosocial interventions are the most commonly used treatments for reducing ADHD symptoms in children and adolescents . Regardin = 7, artificial food color exclusions; n = 8, and free fatty acid supplementation; n = 11) and psychosocial interventions . For all 6 types of interventions results illustrated a reduction in core ADHD symptoms when rated by a person (often unblinded) closest to the therapeutic setting. However, when ratings from persons blind to the treatment condition were evaluated, only free fatty acid supplementation and artificial food color exclusion remained effective in reducing core ADHD symptoms. The authors concluded that the effect sizes found for non-pharmacological treatments are substantially lower than those found in studies on ADHD medication and that better evidence from blinded assessments is needed for psychosocial interventions for ADHD in order to be offered as evidence-based treatments. In an earlier meta-analysis [n = 12.245, ages ranged from 3 to 21 years) with ADHD included 185 RCTs comparing methylphenidate versus placebo or no intervention [In MTA study  579 chilanalysis , 174 stuanalysis  only incanalysis , whereasanalysis  also incanalysis  includedrvention . ResultsIn sum, the international guidelines for treatment of ADHD, supported by the current knowledge about the effectiveness of methylphenidate compared to the somewhat more ambivalent evidence of the effectiveness of other treatment options, suggest that methylphenidate for children with ADHD is, to date, still the first-line treatment . MoreoveBecause of the above named limitations and uncertainties, children and their parents may not view medication as a considerable option. They are not open to try medication but would like to receive non-pharmacological treatment . To concMindfulness training is an intervention based on Eastern meditation techniques, that aims to increase awareness by paying attention on purpose in the present moment, enhance non-judgmental observation, and reduce automatic responding . IndividMindfulness meditation has been incorporated into programs such as Mindfulness Based Stress Reduction (MBSR)  and Minddel = 0.23), surpassing the effects of active control groups. Moreover, findings suggest that mindfulness training may be more beneficial for clinical samples than for non-clinical samples, and also more effective in reducing symptoms of psychopathology than other outcome measures. These studies show preliminary evidence that mindfulness based interventions are also beneficial for youth with a variety of psychological symptoms, as improvements were reported on measures of attention, internalizing and externalizing behavior problems, sleep, anxiety, and academic performance.Although the effects of mindfulness training in adults are well established, research on the effectiveness of mindfulness training in child and adolescent psychiatry is a relatively new domain. The majority of research in this field addresses children and adolescents in non-clinical samples . The metRegarding studies that specifically focused on the effects of mindfulness training for children and adolescents with ADHD (and their parents), so far, 8 studies have been performed.The study of Bögels et al.  includedIn the study of Singh et al. , two chiZylowska et al.  conducten = 18, aged 13-18) and a parallel mindful parenting training for their parents (n = 17), were evaluated using a pre-post-follow-up design and a within-group waitlist control without randomization. At post-test adolescents did not report improvements on any of the measures. However, parents reported a decline in their adolescents’ inattention, conduct problems, and peer relationship problems and in their own parenting stress. Parents also reported an increase in their mindful parenting. Generally, gains achieved during the training were maintained at the 6-week follow-up and adolescents now reported a decrease in their own internalizing problems.In a study of Haydicky et al.  effects n = 9) and a parallel mindful parenting training for their parents (n = 13), using a time-series design during baseline, the training, and six months follow-up [Another study measured the effects of the MYmind mindfulness training for 13-18 year old adolescents with ADHD  with parallel mindful parenting training, using a pre-post-follow-up design and a within-group waitlist control without randomization [n = 10, aged 11–15) with parallel mindful parenting training, using a pre-post-follow-up design without randomization [Finally, two studies were conducted by Bögels and colleagues. The first study  assessedmization . Resultsmization . FindingIn sum, preliminary effectiveness of mindfulness training for children and adolescents with ADHD is clearly demonstrated in the above-mentioned studies. However, the current stage of research in this field is limited by a lack of randomized and controlled  trials with large samples, standardized formats for interventions, objective measures, and that are generalizable outside the intervention context , 67. TheThe primary objective of this RCT is to compare mindfulness training with the currently most effective treatment, methylphenidate, for children with ADHD. To the scope of our knowledge these two treatments have never been compared before in an RCT concerning children with ADHD. Effects of mindfulness training for children combined with mindful parenting training on the primary outcome measures of attention and hyperactivity/impulsivity are compared to those of methylphenidate in children and adolescents with ADHD. In addition, we will compare the effectiveness of mindfulness training versus methylphenidate with respect to: 1) cost-effectiveness; 2) secondary child measures: a) psychopathology, b) stress, c) quality of life, d) happiness, and e) sleep (problems); 3) secondary parent measures: a) parents’ own ADHD and psychopathology, b) stress, c) quality of life, d) sleep (problems), and e) parenting sense of competence; and 4) potential mechanisms of change: a) mindful awareness , b) emotion regulation , and c) parenting (parenting style and mind mindedness). Additionally, treatment adherence (attendance to weekly sessions by parent and child and minutes of home practice by parent and child) will be monitored.A multicenter RCT with follow-up measurements is used to measure the effects of mindfulness training versus the effects of methylphenidate. After enrolment in the study participants sign informed consent and are randomized to the mindfulness arm or the methylphenidate arm. After randomization, participants fill in the pre-test T1) and start the treatment they were assigned to. In the mindfulness arm participants receive 8 sessions of mindfulness training (1 session per week) and in the methylphenidate arm participants start the first 8 weeks of methylphenidate intervention. After those 8 weeks, participants fill in the post-test (T2). Subsequently, for participants in the mindfulness arm, 8 weeks without training follow after T2, and receive a booster session at the end of those 8 weeks. Participants in the methylphenidate arm continue taking methylphenidate for another 8 weeks. Four months (T3) and ten months (T4) after participants started their treatment, follow-up measurements are planned in order to determine whether training effects are long lasting. Between T3 and T4, a 6 month-period passes in which participants do not have to be in treatment, but they are free to consider other treatment options. Thus, participants in the methylphenidate arm can decide to continue their medication, change medication, stop medication, or to remain without treatment, or get enrolled in mindfulness training or another intervention. Participants in the mindfulness arm can decide to remain without treatment, start medication or participate in another intervention. See Fig.  and starIt is anticipated that, given the differences in nature of both treatments, a proportion of potential participants have a strong treatment preference and are, therefore, not willing to be randomized. For this reason a parallel preference study, in which participants choose for one of the two treatments, is conducted in addition to the RCT. This study is approved by the Ethics Review Board of the Faculty of Social and Behavioral Sciences at the University of Amsterdam (no. 2014-CDE-3658). The preference study has similar objectives as the RCT and participants follow, except for randomization, the exact same procedures as participants in the RCT. However, due to expected preference bias in the preference study data is collected and analyzed separately.n = 120) are children and adolescents between 9 and 18 years of age of both sexes diagnosed with ADHD. When children are 8 years old but already in the fifth year of primary school, they are also allowed to participate, since we assume that they are mentally ready to understand the instructions of the mindfulness training. Participants are recruited via referrals of general practitioners or mental health care professionals, study website, media , posters, and flyers. Participating in this study is completely voluntary and participants are free to withdraw from the study and/or the treatment at any moment without having to give a reason and without any consequences for further treatment.Participants (Inclusion criteria are (1) the child has a primary DSM classification of ADHD, (2) ADHD is verified by the child/adolescent version of the Structured Clinical Interview for DSM 5 (SCID-Junior) , (3) theTo verify the inclusion criterion ‘(estimated) IQ is over 80’, an abbreviated version of the Dutch version of the Wechsler Intelligence Scale for Children – Third edition (WISC-III-NL) , 70 is uPsychologists at the two participating treatment centers assess every patient with ADHD for eligibility following the in- and exclusion criteria of this study. When eligible, patients are given the information letter about the content of the study. About a week later, eligible patients are contacted by phone by the researcher, the study procedures are explained, and families are asked for study participation. When verbal consent is obtained, participants are sent the written informed consent on paper, which they can return by mail or hand over during the first appointment with the researcher. Parents sign the informed consent for their own and their child’s or adolescent’s participation. Adolescents (12+) are also requested to sign their own informed consent.The study will be conducted at the urban treatment center UvA minds and the more rural treatment center Buro van Roosmalen. Both centers are outpatient academic treatment centers in the Netherlands, working with children and adolescents with psychiatric problems, and/or family problems.Before children and their parents start the treatment to which they are assigned to, they receive individual psycho-education of 2 to 3 sessions by their psychologist of the treatment center.The mindfulness training is conducted in groups of 4 to 6 participants (children) or 6 to 8 participants (adolescents), and consists of 8 weekly 1.5-h sessions. Eight weeks after the training both children and their parents receive a 1.5-h follow-up session. For the training the MYmind protocol is used: Mindfulness training for Youngsters with ADHD and their parents , 65, 66.Adherence to the homework practices of the mindfulness training is assessed during the eight weeks of the training and the next eight weeks of self-practice using a registration form on which both parents and children fill out their practices on a daily basis. Sessions are videotaped and will be scored on integrity. The MYmind training is delivered by experienced mindfulness trainers who are trained in the MYmind program by the third author, who also provides regular supervision.Short-acting methylphenidate is administered individually and monitored by a child psychiatrist, following the guidelines of “Multidisciplinary guidelines ADHD” . After tAdherence to the methylphenidate treatment is assessed throughout the 16 weeks of the treatment using a registration form filled in on a daily basis by the parent and/or the child.Tables The primary outcome of this study is ADHD symptoms (inattention and hyperactivity/impulsivity) as reported by multiple informants and measured on neuropsychological tasks. ADHD symptoms are measured on 2 subscales (Inattention Symptoms and Hyperactivity/impulsivity Symptoms) of the Dutch parent/teacher version of the Disruptive Behavior Disorder Rating Scale   of the CBCL , TRF 7575, YSR . BehavioADHD symptoms of parents are measured with the Self-report Questionnaire for Inattention and Hyperactivity   as a possible working mechanism underlying the effect of the MYmind training and the mindful parenting training is measured by a) the Children’s Acceptance and Mindfulness Measure , 93  the Healthy Self-Regulation Subscale   the Parenting Scale , 103 , at T1, T2, T3, and T4. As there are six months between T3 and T4 and the cost questionnaire only covers two months, the cost questionnaire will also be completed twice in between these two measurement occasions. For the cost questionnaire a modified version, specially adapted to families with children with ADHD, of the cost questionnaire applied in Van Steensel et al.  will be We expect methylphenidate to have a large effect on ADHD symptoms at T2 and T3 . Based on = 60) and methylphenidate (n = 60). Stratified randomization is used to ensure that the ratio of boys and girls is equal in both the mindfulness group and the methylphenidate group. Randomization is carried out separately for UvA minds and Buro van Roosmalen and also separately for both age groups (children and adolescents). The first author will allocate participants to a treatment group using a computer-generated list of random numbers.Participants are randomized over mindfulness  analysis, as data collected at different measurement occasions  form a hierarchical structure of measurements nested within persons. Experimental effects are indicated by significant parameters for group by time interactions. Effects of mindfulness training on inattention and hyperactivity/impulsivity are compared to effects of methylphenidate on inattention and hyperactivity/impulsivity. Also effects of mindfulness training on the secondary outcome measures are compared to effects on methylphenidate using multilevel (mixed model) analysis. Impact of covariates, such as social economic status, expectations of how helpful the treatment will be, stratification factors , and ADHD symptom severity at T1 will be evaluated. Effect sizes and corresponding 95 % confidence intervals will be presented. Background information  will be used for descriptive purposes.Possible underlying mechanisms of change, will be evaluated using a multiple mediation model following the principles and practice of structural equation modeling as described in Preacher and Hayes .The ICER and its 95 % confidence interval will be calculated using bootstrap analysis. This analysis results in a scatterplot of bootstrapped ICERs  with four quadrants (1) bootstrapped ICERS falling in the north-east quadrant reflect higher effects costs for mindfulness compared to medication, (2) bootstrapped ICERs falling in the south-east quadrant reflect higher effects and lower costs for mindfulness compared to medication, (3) bootstrapped ICERs falling in the south-west quadrant reflect lower effects and costs for mindfulness versus medication, and (4) bootstrapped ICERs falling in the north-west quadrant reflect lower effects and higher costs for mindfulness compared to medication. In addition, acceptability curves will be obtained representing the chance that mindfulness is a cost-effective intervention compared to medication. Given the non-parametric approach of bootstrap analysis there is no required assumption about the distribution of the data . The cosAll participants will be assigned a unique code. Access to the key of this coding system (an SPSS coding file) is limited to the coordinating investigators and the principal investigator. When necessary, the auditor, the Medical Ethical Committee of the Amsterdam Medical Center, and employees of the Health Care Inspection (Inspectie voor de Gezondheidszorg) can access this coding system. On the informed consent papers, the name of the participant and the code of the participant are presented. Hence, the consent papers of the participants will be stored in a separate organizer, with access limited to the above mentioned persons. The questionnaires will be completed at home, after the participant is sent a link to the online questionnaire. This link is connected to the unique code of the participant. This way all the questionnaire data can be coded and analyzed anonymously.The study and the participating centres have a liability insurance which is in accordance with article 7, subsection 6 of the Medical Research Involving Human Subjects Act (WMO). The study also has an insurance which is in accordance with the legal requirements in the Netherlands . This insurance provides cover for damage to research subjects through injury or death caused by the study. The insurance applies to the damage that becomes apparent during the study or within four years after the end of the study.ADHD is a highly prevalent childhood disorder  and is aAn anticipated limitation of this study is a nonparticipation bias , as it iTo conclude, this study will be the first to reveal whether mindfulness treatment for children with ADHD can be provided as an alternative to the current standard treatment of medication, and may reveal which mechanisms of change contribute to the effectiveness of the interventions. This study has the potential to impact clinical practice in important ways, as at present most children referred with ADHD receive medication, despite its disadvantages.ADHD, Attention-Deficit-Hyperactivity-Disorder; ASR, Adult Self Report; CAMM, Children’s Acceptance and Mindfulness Measure; CBCL, Child Behavior Checklist; CSRQ, Chronic Sleep Reduction Questionnaire; DBDRS, Disruptive Behavior Disorder Rating Scale; DSM, Diagnostic and Statistical Manual of Mental Disorders; EDT, Emotion Discussion Task; FFMQ, 5 Facet Mindfulness Questionnaire; HSDQ, Holland Sleep Disorders Questionnaire; HSR, Healthy Self-Regulation Subscale; ICER, Incremental Cost-Effectiveness Ratios; IM-P, Interpersonal Mindfulness in Parenting scale; MBCT, Mindfulness Based Cognitive Therapy; MBSR, Mindfulness Based Stress Reduction; MM, Mind Mindedness; MTA, Multimodal Treatment of Attention Deficit Hyperactivity Disorder; NWO, Netherlands Organisation for Scientific Research; PS, Parenting Scale; PSOC, Parenting Sense of Competence; PSQI, Pittsburgh Sleep Quality Index; PSS, Perceived Stress Scale; QUALY, Quality Adjusted Life Year; RCT, randomized controlled trial; SCID, Structured Clinical Interview for DSM; SCS, Self Compassion Scale; SHS, Subjective Happiness Scale; SQC, Stress Questionnaire for Children; SQIH, Self-report Questionnaire for Inattention and Hyperactivity; TEA-Ch, Test of Everyday Attention for Children; TOF, Test Observation Form; TRF, Teacher’s Report Form; WHO-5, World Health Organization Well-Being Index; WISC, Wechsler Intelligence Scale for Children – Third edition; YSR, Youth Self Report.


BiOCOOH hollow spheres and flower-like structures, which are both assembled by 2D BiOCOOH nanosheets, were prepared first by a “bottom-up” route through a “quasi-emulsion” mechanism. Then the BiOCOOH hierarchical structures were transferred to hierarchical Bi2S3 architectures through an “up-down” route by an ion exchange method. The obtained Bi2S3 nanostructures remain hollow-spherical and flower-like structures of the precursors but the constructing blocks are changed to 2D sheet-like networks interweaving by Bi2S3 nanowires. The close matching of crystal lattices between Bi2S3 and BiOCOOH was believed to be the key reason for the topotactic transformation from BiOCOOH nanosheets to 2D Bi2S3 sheet-like nanowire networks. Magnetism studies reveal that unlike diamagnetism of comparative Bi2S3 nanostructures, the obtained multi-level Bi2S3 structures display S-type hysteresis and ferromagnetism at low field which might result from ordered structure of 2D networks.A bottom-up-then-up-down route was proposed to construct multi-level Bi One-dimensional 1D) nanostructures such as tubes, rods and wires have aroused intensively attention due to their distinct properties and potential applicationsD nanostr24589102S3), as an important layer-structured semiconductor with a direct band gap of 1.3 eV, has potential applications in many fields including catalysis, sensor, optoelectronic nanodevice and lithium ion battery122S3 structures and different Bi2S3 architectures such as snowflake-like, core-shell microspheres, sheaf-like and crossed nanofabrics have been prepared1415162S3 with multi-level architectures based on 1D nanostructures have not been accomplished yet. Herein, we present a topotactic transformation route for multi-level Bi2S3 architectures assembled by 2D sheet-like networks interweaved by 1D nanowires. Hollow spherical and flower-like BiOCOOH structures assembled by BiOCOOH nanosheets were first prepared by a “bottom-up” route through a “quasi-emulsion” mechanism. Then the BiOCOOH hierarchical structures were transferred to multi-level hierarchical Bi2S3 architectures through an “up-down” route by an ion exchange method. The obtained Bi2S3 nanostructures remained hollow-spherical and flower-like structures of the precursors but the constructing blocks changed to 2D sheet-like networks interweaved by Bi2S3 nanowires. Magnetism studies reveal that the novel multi-level structures display different magnetic behaviors from the diamagnetism of the comparative Bi2S3 structures.Bismuth sulfide (Bi3)3 in glycerol, H2O and DMF mixture. The BiOCOOH structure were prepared by solvothermally treating Bi(NO2S3 complex architectures through an “up-down” ion exchange method by mixing thioacetamide (TAA) and BiOCOOH in 20 mL of H2O, followed by hydrothermal treatment at 120 °C for 12 h. XRD pattern of the product is shown in 2S3 , indicating that the BiOCOOH structures were completely transformed to Bi2S3 crystals. 2S3 structures. A panoramic SEM image presented in 2S3 sample is composed of microspheres in large scale with an average diameter of about 2 μm. The hollow nature of the Bi2S3 spheres can be clearly seen from 2S3 hollow microspheres are constructed by 2D sheet-like networks as magnified SEM images show in 2S3 hollow spheres are multi-leveled superstructures. The 2D sheet-like Bi2S3 networks are interwoven by crossed Bi2S3 nanorods with long range order. The nanorods are uniform with a diameter of about 20 nm and the angle between the adjacent nanorods is about 90°. It is worth to mention that such multi-leveled complex hollow Bi2S3 superstructures assembled by 2D disc-like networks have never been reported before. The corresponding TEM images of the microspheres presented in 2S3 structures are hollow by clearly displaying a contrast between the dark edges and the pale center and made of crossed nanorods with a diameter of about 20 nm. EDX and XPS were both used to demonstrate the formation of the products. From the EDX pattern shown in Figures S1c, only Bi and S along with Au can be detected, confirming the pure nature of the obtained hierarchical structures. XPS characterizations as shown in 2S3.The acquirement of hierarchical BiOCOOH structures brings us opportunities to construct multi-level architectures through topotactic transformation. In this study, the hierarchical BiOCOOH structures were transformed to Bi2S3 sheet-like networks obtained by sonicating the complex Bi2S3 hollow microspheres was further characterized by TEM and HRTEM. As shown in 2S3 networks are interwoven by crossed Bi2S3 nanorods with a diameter of about 20 nm and the angle between the adjacent nanorods of about 90°. The SAED pattern corresponding to the whole 2D sheet-like networks shown in 2S3 nanorods are interwoven into the network in a tetragonal symmetry. It also reveals that the perpendicularly aligned nanorods might have preferential growth direction of [001]. 2S3 nanorod display the lattice spacing of about 0.36 nm, which is consistent with the spacing of (130) planes of orthorhombic Bi2S3. Although the fringes of the (001) facet are not found in the image, it can still be proposed that the nanorods grow along the [001] direction, which is perpendicular to (130) facets.The crystalline structure of the 2D Bi3)3 was solvothermally treated in H2O and DMF, no BiOCOOH hollow spheres but flower-like BiOCOOH structures were obtained. Based on the experiment results, a “quasi-emulsion-templated” mechanism is proposed for the BiOCOOH hollow spheres in glycerol and water mixture181922233)·5H2O was added into the mixture of water and glycerol, the coordination between BiIII and glycerol would make BiIII gather onto the surface of the emulsified spheres. As reaction temperature increases, DMF hydrolyze into formic acid to react with BiIII to form BiOCOOH. Driven by the minimization of interfacial energy and templated by the emulsified spheres, the sheet-like BiOCOOH aggregate around the emulsified spheres and lead to the formation of hierarchical BiOCOOH hollow spheres. The formation process of BiOCOOH hollow spheres can be illustrated as shown in In the reaction system glycerol plays an important role for the formation of hollow BiOCOOH spheres. Without the addition of glycerol, when Bi and the c-axis of orthorhombic Bi2S3 (c = 3.981 Å) could be responsible for the formation of 2D Bi2S3 sheet-like networks92− and HCOO- ions in BiOCOOH nanosheets to form [001]-oriented Bi2S3 nanorods lying on the top surfaces of BiOCOOH nanosheets. The [001]-oriented Bi2S3 nanorods would have a tendency to oriented along the two perpendicular [100] and [010] directions of BiOCOOH because of the close lattice matching between the a- or b- axis of BiOCOOH and the c-axis of Bi2S3, which finally leads to the formation of 2D Bi2S3 sheet-like networks. The topotactic transformation process remains the spatial structure of the precursor and leads to the multi-level construction of complex Bi2S3 hollow microspheres assembled by 2D sheet-like networks. The topotactic transformation process can be confirmed by reducing the reaction times. During the transformation from BiOCOOH to Bi2S3, intermediate mixtures BiOCOOH and Bi2S3 were detected when the reaction time was 1 h and 3 h. Corresponding XRD patterns and SEM images were presented in 2S3 became stronger, indicating that more Bi2S3 crystals formed. From the SEM investigations, the form Bi2S3 formed on the surface of BiOCOOH nanosheets in an oriented direction. The process can be further proved by transforming BiOCOOH flower-like structure to Bi2S3 superstructures. As SEM and TEM images shown in 2S3 flower-like superstructures assembled by 2D sheet-like networks. In the other hand, when we tried to transform BiOCOOH structures to form Bi2Te3 structures, such novel multi-level structures can’t be obtained. 2Te3 crystals have been obtained . However, the SEM investigations 3 and thiourea at 160 °C for 16 h, whose SEM images are shown in M-H) loops at room temperature of all the three samples including the comparative Bi2S3 nanostructures, the obtained multi-level Bi2S3 hollow spheres and flower-like structures. For the comparative Bi2S3, a diamagnetic M-H curve was observed, revealing that the conventional Bi2S3 material is intrinsic diamagnetic. Interestingly, for the novel multi-level Bi2S3 superstructures, the M-H curve transits to be S-type hysteresis, suggesting the appearance of ferromagnetic long-range ordering in the multi-level Bi2S3 superstructures at low fields. M-H curve from -2000 Oe ~2000 Oe, exhibiting typical ferromagnetic hysteresis loops at room temperature with coercivity forces of about 84 Oe and 40 Oe for superstructured Bi2S3 hollow spheres and flowers, respectively. At larger magnetic field part, the obtained Bi2S3 superstructures also exhibit diamagnetic behaviors arising from the intrinsic Bi2S3 because of the decrease of magnetization. In the experiments, all the used chemicals were analytic grade and all the three samples were prepared through the same route and the same treatment procedure. So, although to reach a clear conclusion requires further investigations, the difference in the magnetic properties of the comparative Bi2S3, the multi-level Bi2S3 hollow spheres and flower-like structures would probably rise from their different structures.Magnetic properties of the multi-level Bi2S3 superstructures, hollow spheres and flower-like structures constructed by 2D sheet-like networks, have been successfully synthesized using BiOCOOH as the precursors through a “bottom-up-then-up-down” topotactic transformation process. The glycerol in the reaction system plays an important role for the formation of hierarchical BiOCOOH hollow structures and the crystal lattice matching is demonstrated to be responsible for the topotactic transformation from BiOCOOH to Bi2S3 to construct the multi-level hierarchical structures. Unlike diamagnetism of comparative Bi2S3 nanostructures, the obtained multi-level Bi2S3 structures display ferromagnetism at low field.In summary, novel multi-level Bi3)·5H2O was dissolved in 12 mL of glycerol, 3 mL of H2O and 5 mL of DMF to form a stable transparent solution under vigorously magnetic stirring. Then the obtained homogeneous solution was transferred into a 50 mL Teflon-lined stainless steel autoclave and sealed to heat at 160 °C for 12 h. After heated, the autoclave was cooled to room temperature naturally. The obtained precipitate was collected and washed with ethanol and de-ionized water in sequence by centrifugation, and then dried at 50 °C for 12 h. For the synthesis of flower-like BiOCOOH structures, 1.0 mmol of Bi(NO3)·5H2O was added to 15 mL of H2O and 5 mL of DMF under magnetic stirring for several minutes. Other experimental conditions remained the same as that of BiOCOOH hollow spheres.All chemical agents were of analytical grade and purchased from Shanghai Chemical Reagent Factory and used directly without further purification. For the synthesis of BiOCOOH hollow spheres, 1.0 mmol of Bi and 1.5 mmol of thioacetamide (TAA) was added into 20 mL of Hα radiation (λ = 1.5418 Å). The morphologies of the samples were investigated on a Hitachi S-4800 field-emission scanning electron microscope (FE-SEM) at an acceleration voltage of 10.0 KV. Transmission electron microscopy (TEM), high-resolution TEM (HRTEM) images and the corresponding selected area electron diffraction (SAED) were obtained on the JEOL JEM-2100 transmission electron microscope at an acceleration voltage of 200 KV. The magnetic measurements were carried out using a SQUID magnetometer (Quantum Design) at 300 K.The phases of the obtained samples were characterized by X-ray diffraction (XRD) on a Shimadzu XRD-6000 powder X-ray diffractometer with Cu KHow to cite this article: Wei, C. et al. Bottom-up-then-up-down Route for Multi-level Construction of Hierarchical Bi2S3 Superstructures with Magnetism Alteration. Sci. Rep.5, 10599; doi: 10.1038/srep10599 (2015).


Since the first quantum ghost imaging (QGI) experiment in 1995, many QGI schemes have been put forward. However, the position-position or momentum-momentum correlation required in these QGI schemes cannot be distributed over optical fibers, which limits their large-scale geographical applications. In this paper, we propose and demonstrate a scheme for long-distance QGI utilizing frequency correlated photon pairs. In this scheme, the frequency correlation is transformed to the correlation between the illuminating position of one photon and the arrival time of the other photon, by which QGI can be realized in the time domain. Since frequency correlation can be preserved when the photon pairs are distributed over optical fibers, this scheme provides a way to realize long-distance QGI over large geographical scale. In the experiment, long-distance QGI over 50 km optical fibers has been demonstrated. How to realize photonic quantum information applications over long-distance optical fibers is an important topic of quantum engineering, considering the extensive optical fiber links over globe. Quantum information applications realized over optical fibers, can support related, interesting applications over large geographical scale, such as quantum key distribution (QKD)45678910111215In recent years, the effect of temporal dispersion on the correlated/entangled photon pairs has attracted much attention and been used in many applications, such as the manipulation of the single photon wave packetFrequency correlated photon pairs can be generated in third order nonlinear waveguide by the spontaneous four wave mixing process2324ωp is the frequency of the pump light. The indices s and i indicate the signal photons (with frequency ωs) and idler photons (with frequency ωi), respectively. f(Ω) is the spectral amplitude of the biphoton state.where xΩ in the line. The reflectivity pattern along the illuminating line would modulate the spectrum of the reflected signal photons, and also that of the frequency correlated photon pairs, which can be looked as a special form of wave packed reshaping based on energy-time entanglementThe signal and idler photons are distributed to two parties, named Alice and Bob, over optical fibers. At Alice side, there is an object with a specific reflectivity pattern. The signal photons are firstly dispersed to different directions along a line according to their frequencies by a spatial dispersion component, such as a grating. Then they illuminate the object along a line, which is named as the illuminating line. Signal photons with different frequenciy will arrive at different positions on the object. The signal photons with a specific frequency detuning Ω would arrive at a specific position ωp + Ω. ts is the detection time of the signal photons, Ls is the length of the optical fiber between the photon-pair source and the SPD at Alice side. Assuming that Ls is small, the group velocity dispersion (GVD) in the fiber has been neglected. The phase coefficient of the signal photons in the fiber has been expanded in the vicinity of ωp + Ω0 , which is the central frequency of signal photons, as βs(ωp + Ω) = βs0 + βs1(Ω − Ω0).where Li, then the positive-field operator of the idler photons at time ti can be expressed asAt Bob side, the idler photons are temporally dispersed before detected by a SPD. The most convenient way to realize the dispersion is utilizing the GVD of the transmission fiber, by which the idler photons are sent to Bob side from the source. If the length of the optical fiber between the photon-pair source and the SPD at Bob side is ai(ωp − Ω) is the annihilation operator for idler photons at the frequency ωp − Ω. The phase coefficient of the idler photons in the fiber can be expanded aswhere ωp − Ω0 is the central frequency of idler photons. The term with βi2 is corresponding to the GVD. Higher order dispersions in the fiber have been neglected.where G(2). Under the assumption that the temporal dispersion introduced at Bob side is large enoughG(2) function can be expressed asThe signal and idler photons are detected by SPDs at both sides with arrival time recorded. Then Alice sends the single photon events to Bob. Time discriminated coincidence measurement can be carried out at Bob side. It can be analyzed by the second-order Glauber correlation function where r(xΩ) can be extracted from the coincidence measurement result. In this scheme, the signal photons are detected without discriminating their frequency and arrival time, hence, the reflectivity pattern along the illuminating line can not be recovered by Alice side only. On the other hand, the idler photons are discriminated according to their frequencies by the arrival time, supporting the nonlocal imaging process in the way of QGI.According to 27The principle can be explained by the transformation of quantum correlation in this scheme. At Alice side, signal photons with different frequencies are mapped to different illuminating positions on the object due to spatial dispersion component. While, at Bob side, the idler photons with different frequencies have different arrival time due to the GVD of the fibers. Hence, the frequency correlation in the photon pairs is transformed to the correlation between the illuminating positions of signal photons on the object and the arrival time of idler photons. Compared with QGI schemes based on momentum-momentum or position-position correlationλs0 = 1530 nm and λi0 = 1570 nm, respectively.In the experiment, the frequency correlated photon pairs are generated by the SFWM process in a silicon nanowire waveguideThe joint spectrum density (JSD) of the biphoton state is measured by the method shown in ref. e2 diameter of 2.1 mm. A reflective diffraction grating  is used to disperse the signal photons spatially. After a lens with a focal length l = 25.4 mm, the signal photons are focused on the surface of the object along a line, i.e., the illuminating line, with a length of about 250 μm. The signal photons with different frequencies would be focused on different positions along the illuminating line. The object is a standard photolithographic mask, which is a silica plate with a patterned chrome layer. It provides a reflectivity pattern. The signal photons are partially reflected according the reflectivity pattern along the illuminating line, resulting in modulated spectrum. The reflected signal photons are collected by the collimator and sent to a SPD  through the CIR. The single-photon events are recorded with high time-resolution using a time recoder (TR1) in a photon correlator .The sketch of the setup for long-distance temporal QGI is shown in 29d = 900 ps/nm (estimated by the group velocity dispersion parameter of SMF). Since the bandwidth of idler photon is 16 nm, the idler photons are temporally broadened to 15.4 ns.While, the idler photons are sent to Bob through 50 km-long SMF. Then the idler photons are detected by the other SPD and the single photon events are also recorded with high time-resolution (TR2). On one hand, the frequencies of the idler photons are preserved after the propagation through such a long fiber, hence, the long distance distribution of the frequency correlated biphoton states is realized. On the other hand, the transmission fiber provides a GVD of When sufficient single photon events are collected at Alice and Bob sides, Alice should send the records of the detected signal photons to Bob by a classic channel, and Bob could realize coincidence measurement utilizing recorded signal and idler photon events. In the experiment, the single photon events at both sides are recorded by two channels of the photon correlator with a resolution of 164.61 ps, and the coincidence is calculated by a computer according to the records. A typical measurement result is shown in By step-moving the object along the direction orthogonal to the illuminating line, two-dimensional imaging of the object can be obtained, which is shown in To analyze the resolution of our QGI scheme, another object with narrower line width is used, as shown in Along the illuminating line, a reflectivity point at the object has a point-spread spectral function, which has a full width at half maximum (FWHM) determined by the resolving power of the gratingN is the total number of grooves in the beam area on the grating. The point spread spectral function will result in a point-spread coincidence peak, with a FWHM ofwhere d is the temporal dispersion at Bob side. On the other hand, the impact of the single photon detecting system is denoted by δτ2, including the effect of timing jitters of two SPDs and the time resolution of photon correlator. Hence, the resolution of the temporal QGI can be estimated bywhere θ0 is the diffraction angle of the signal photons with wavelength λs0, p is the period of the grating. The relation p(sin θ − sin θi) = λ between the diffraction angle θ of the signal photons, the wavelength λ and the incident angle θi, has been used in the equation.where, l = 0.0254 μm, p = 1.67 μm, θ0 = 11.9°, λs0 = 1530 nm, N = 1044 grooves, δτ2 = 389 ps, d = 900 ps/nm), the calculated spatial resolution is about 23.8 μm, agrees well with the experiment results considering the fact that the reflectivity of the object has a rectangluar profile.According to the parameters of the experiment setup  and high performance photon correlator (timing jitter ~12 ps). If the diameter of the signal photon beam is expended to 5 mm and an objective lens with a focal length of 5 mm is used, a resolution as high as 1.1 μm can be expected.As a conclusion, we proposed a scheme of temporal QGI. By introducing the temporal dispersion and spatial dispersion on the two photons with frequency correlation respectively, the frequency correlation is transformed to the correlation of arrival time and propagation direction, which is used to realize QGI in time domain. Since the frequency is a stable DOF of photons traveling in optical fibers, it provides a way to realize long distance QGI over optical fibers. It is demonstrated by the experiment with 50-km long SMF, in which the 2-dimensional QGI is realized by step-moving the object like a “quantum fax machine”. The spatial resolution of this scheme is analyzed, showing that it could be less than the wavelength of the illuminating photons by proper system design. This scheme overcomes the obstacle on realizing QGI over large geographical scale, which may inspire new applications in quantum engineering.This section discusses the relation between the scale of the object and the image. It is clear that in the direction orthogonal to the illumiating line, the scale of the image should be equal to the scale of the object. In the following, we focus on the scale transformation relation in the direction of the illuminating line.xΩ on the object and the signal photon frequency ωp + Ω can be expressed asAt Alice side, the relation between the illuminating position ωp + Ω0 , l is the focal length of the lens, c is the velocity of light in vacuum, θ is the diffraction angle of light beams after grating, and λ is the wavelength of signal photons, which is corresponding to the frequency by the relation λ = 2πc/(ωp + Ω). As we use the first order of interference of the grating, the angle of the incident light θi, the angle θ of the diffration light with wavelength λ, must satisfy the equationp is the period of the grating. Hence,where θ0 is the diffraction angle of signal photons with frequency ωp + Ω0. Two points with high reflectivity on the object with distance Δx will reflect signal photons with frequency differency equal towhere, θ0 is the diffraction angle of signal photons with frequency ωp + Ω0.where, According d and βi2, i.e. d asConsidering the relation between the dispersion parameter of λs0 is the central wavelength of signal photons, and λs0 = 2πc/(ωp + Ω0).where How to cite this article: Dong, S. et al. Long-distance temporal quantum ghost imaging over optical fibers. Sci. Rep. 6, 26022; doi: 10.1038/srep26022 (2016).


It is estimated that 2–3% of children in the US have hypertension (HTN) and 8% of children ages 4–17 carry the diagnosis of attention-deficit hyperactivity disorder (ADHD). The prevalence of HTN and cardiovascular (CV) risk factors in children with ADHD on CNS stimulant treatment (stimulants) compared to no treatment and compared to their healthy counterparts is not well described. Using National Health and Nutrition Survey data, we examined demographic, blood pressure (BP) and CV risk factors of 4,907 children aged 12–18 years with and without the diagnosis of ADHD, and further examined the CV risk in a subgroup of ADHD patients on stimulants. Three hundred eighty-three (10.7%) children were reported to have ADHD, of whom 111 (3.4%) were on stimulants. Children with ADHD on stimulants were significantly younger, male, and white compared to those with ADHD not on medication and those without ADHD. Body mass index (BMI), eGFR, cholesterol, the prevalence of albuminuria, and poverty were not significantly different between the three groups. One hundred sixty (2.7%) had BP in the hypertensive and 637 (12.4%) in the pre-hypertensive range. The prevalence of elevated BP (HTN and/or pre-HTN range) was not different between children with ADHD on stimulants compared to ADHD without medication and those without ADHD. Heart rate (HR) was significantly higher in the ADHD group on stimulants vs. the groups ADHD on no stimulants and without ADHD. When the relationship between stimulants and the risk of abnormal BP was examined, there was a significant interaction between having BP in the HTN range and sex. After adjusting for BMI, race, and age, females with ADHD on stimulants tended to be older and had significantly more BP in the hypertensive range. On the other hand, males were more likely to be of a white race and older, but not hypertensive. Children with ADHD on stimulants have significantly higher HR than children with ADHD on no stimulants and children without ADHD. On the other hand, the prevalence of abnormal BP classification is comparable between the three groups. Hypertension (HTN) in children and adolescents has been associated with target organ damage. It has been reported that as many as 34–38% of young adults with mild blood pressure (BP) elevation demonstrate left ventricular hypertrophy, which is the most common manifestation of target organ damage in childhood and adolescent HTN. Other associated comorbidities include retinopathy, cognitive impairment, and decreased glomerular filtration rate (GFR) and atherosclerotic plaques in the aorta and carotid arteries –4.Centers for Diseases Control and Prevention (CDC) analysis of data from the 2007 National Survey of Children’s Health (NSCH)  found 9.Stimulants are the mainstay of ADHD treatment. The effectiveness of stimulants in treating ADHD has been well documented. However, in 2006, because of concern over the cardiovascular (CV) effects of ADHD stimulants, the Drug Safety and Risk Management Advisory Committee of the Food and Drug Administration suggested a “black box” warning on stimulant drugs to treat ADHD  1999–2004, we examined demographic and CV risk factors in children with and without the self-reported diagnosis of ADHD. In addition, we examined CV risk factors in children with ADHD on CNS stimulant medications. Finally, since differences in prevalence of ADHD, medication treatment of ADHD, and abnormal BP have been reported by sex, we tested a hypothesis of an interaction between BP and sex among children with ADHD on CNS stimulants.Data from NHANES for the years 1999–2004 were analyzed. NHANES is an ongoing nationally representative cross-sectional survey of the civilian, non-institutionalized US population that uses a complex, stratified, and multistage probability design. The survey is performed by the National Center for Health Statistics at the CDC and released in 2-year increments. Survey participants underwent standardized interviews, physical examinations, and laboratory testing in their homes and at a mobile examination center (MEC). Height, weight, and BP measurements were obtained on all NHANES participants aged 12–18 years.National Health and Nutrition Survey 1999–2004 was approved by the National Center for Health Statistics Institutional Review Board. All of the participants 18 years of age provided informed consent and for those participants under the age of 18 years, parents/guardians provided informed consent.Participant use of CNS stimulants was obtained from self-report. A personal interview was conducted as part of NHANES protocol and participants were queried on use of prescription medication during a 1-month period prior to the survey date. Participants 16 years of age and younger had a proxy respond for them while those older than 16 years responded for themselves.Demographic variables included in the current study are age (years), sex, and self-reported race/ethnicity . Poverty–income-ratio (PIR) is a ratio of a family’s income to the poverty threshold as defined by the US Census Bureau. A PIR ≤1 was defined as below the poverty threshold by NHANES.Physical examination measures were obtained in the MEC according to standardized protocol . Three s2). BMI z-scores were calculated based on 2000 CDC growth charts (Body mass index (BMI) was calculated as weight in kilograms divided by height in meters squared . p-Values were calculated by weighted least squares or weighted logistic regression analyses. Continuous, abnormally distributed variables are presented as median . Given that the prevalence and use of medication for ADHD is more common among males, we tested the hypothesis that BP (systolic and diastolic percentile) was influenced by the sex of the ADHD child. An interaction product term of sex × BP percentile (systolic and diastolic separately) was entered into two regression models to represent the interaction. Statistical regression models adjusted for ADHD (with and without CNS stimulant use), age, BMI z-score, ethnicity (white vs. non-white), fasting glucose, total cholesterol, eGFR, CRP, HR, and poverty.Continuous, normally distributed variables are presented as mean ± SD and categorical variables are presented as % .n = 383) had a self-reported diagnosis of ADHD; 7.3% (n = 272) were not on ADHD CNS stimulant medications; and 3.4% (n = 111) were on CNS stimulant medications. Mean age was 15 years (SD 2.8). Children with ADHD on CNS stimulant medication were significantly younger, male, and white (p < 0.05) compared to those with ADHD not on medication and those without ADHD. HR was significantly higher in children with ADHD on CNS stimulants (81.72 beats/min) compared to children with ADHD and not on stimulants (76.33 beats/min) and children with no ADHD (76.76 beats/min)  children had a mean BP in the hypertensive and 12.4% (n = 637) in the pre-hypertensive range. The prevalence of abnormal BP (hypertensive and/or pre-hypertensive range) was not significantly different between children with ADHD on CNS stimulant medication compared to children with ADHD without medication and those without ADHD. Systolic and diastolic BP percentiles were also not significantly different between the three groups  in models that included both main effect terms along with ADHD (with and without CNS stimulant use), age, BMI z-score, ethnicity (white vs. non-white), fasting glucose, total cholesterol, eGFR, CRP, HR, and poverty.In linear regression models with systolic and diastolic BP percentile  as the outcome, we tested the hypothesis that BP may be influenced by the sex of the child with ADHD on CNS stimulants. A product interaction term of sex × systolic and diastolic BP percentile was entered into two separate regression models along with the lower level terms. The interaction terms (sex × systolic BP percentile) and (sex × diastolic BP percentile) were statistically significant (Table n = 26) is 2.5 times greater than for males (n = 85); 6.76 compared to 2.61.Tables z-score, eGFR, and HR were significant predictors of diastolic BP percentile while adjusting for other covariates. Among females only age was a significant predictor of diastolic BP percentile.For both males and females BMI To our knowledge, this is the largest study to examine the effect of CNS stimulant medication use on BP classification in a study population representative of the US children and adolescents. In this study, we report comparable prevalence of elevated BP (pre-hypertensive and hypertensive range) between patients with self-reported ADHD vs. no ADHD diagnosis. Also, we report comparable prevalence of elevated BP between the ADHD patients on stimulant medications vs. no medications. HR was significantly higher in the group on CNS stimulant medications compared to children with ADHD on no stimulants and no ADHD.It is important to point out that children with self-reported ADHD on stimulant medications had a slightly higher systolic BP percentile, which was not significantly different between the groups and did not change BP classification. We also report a significant difference in BP classification by sex; females with ADHD are significantly more hypertensive, while males with ADHD on CNS stimulants had a significantly higher HR.Ten percent of this nationally representative sample of 4,907 children had ADHD. One-third of children with ADHD were on medications, 90% of whom were on CNS stimulants. Methylphenidate and amphetamine–dextroamphetamine were the two most commonly used medications.p < 0.001] and systolic BP findings  compared with subjects randomized to placebo (p = 0.02) and waking diastolic BP  were significantly higher during active treatment. Total HR was also significantly higher during active treatment  ,  placebo . Samuels= 0.004) . In a sy= 0.004) .p = 0.01); in the atomoxetine group after 6 months in diastolic pressure  and in HR , and after 12 months in HR   on CV variables in 114 adolescents with ADHD, they reported small but statistically significant changes in DBP and HR at 6 weeks, without further increases up to 6 months follow-up. A small but not statistically significant increase in SBP was observed at 6 weeks, this increase was statistically significant at 6 months of follow-up . It is i= 0.003) .In adults, high HR has proven to be a strong predictor of CV disease and a predictor of the development of essential HTN. Whether HR itself is a risk factor for development of HTN or just a marker for sympathetic over activation is still a matter of debate , 20.Previous studies showed a small increase in HR and BP measurements. It is important to point out that while children on CNS stimulant treatment in our study had similar effects, those small changes in BP measurements did not change BP classification range between the different groups. On the other hand, it is important to remember that the long-term CV effects of elevated resting HR and the small increases in BP are not well defined in children and may contribute to an increased future CV risk. Using two large administrative databases, Schelleman and colleagues compared the rate of severe CV events and death in children who use attention-deficit/hyperactivity disorder (ADHD) medications vs. non-users. They found the rate of CV events in exposed children to be very low and in general no higher than that in unexposed control subjects. Because of the low number of events, they had limited ability to rule out relative increases in event rate .We found males with ADHD on CNS stimulants had a lower BMI and significantly higher CRP levels. While it is well described that treatment with CNS stimulants can depress growth in hyperactive children on stimulant drugs , the relThe relationship between BP and GFR is complicated. In our study, higher GFR was an independent determinant of systolic BP in females and diastolic BP in both males and females Tables  and 4. TOur study is limited by its cross-sectional design and the inability to draw any causal relationships. All three BP measures were taken at one sitting 5 min apart. As such, none of the children included in the study can be diagnosed truly hypertensive or pre-hypertensive based on the fourth report recommendations. Rather, the average of three BP measures here serve as a proxy for BP status similar to many other published studies , 9. Anotclassified each patient’s BP based on the average of three measurements obtained during the survey exam and adjusted for height and sex: normal BP, hypertensive, or pre-hypertensive range. In this study, we were able to compare a subgroup of self-reported ADHD patients on CNS stimulants to a larger group of self-reported ADHD patients on no medications as well as to healthy counterparts.On the other hand, this study has a number of strengths in that it examines a large pediatric cohort, representative of the US population. Also, in this study, we Overall, children on CNS stimulants tend to have higher HRs and slightly higher BP percentiles. The difference in BP percentiles did not translate into a difference in the prevalence of BP in the hypertensive and/or pre-hypertensive ranges between children with ADHD on stimulant treatment vs. no treatment and was comparable to children without ADHD. Sex differences in BP classification may exist in children on CNS stimulant treatment. These findings as well as the higher CRP levels in males on CNS stimulants need to be confirmed by future studies. Prescribers of CNS stimulant medication need to be aware of the potential long-term adverse effects of these medications and need to weigh the risk and benefits when starting stimulant treatment.Authors  had substantial contributions to the conception or design of the work; or the acquisition, analysis, or interpretation of data for the work; and all authors contributed to drafting the work or revising it critically for important intellectual content; and the final version was approved by all authors. All authors agree to accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


To determine whether children with attention deficit hyperactivity disorder (ADHD) and mild intellectual disability (ID) are a clinically distinct ADHD subgroup.This was a cross-sectional study comparing clinical characteristics  between children with ADHD and mild ID and those with ADHD and IQ test scores >70, and also between children with ADHD and ID and a general population sample of children with ID alone. The sample comprised a clinical sample of children with ADHD with ID (n = 97) and without ID (n = 874) and a general population sample of children with ID and without ADHD (n = 58).After correcting for multiple statistical tests, no differences were found between the 2 ADHD groups on any measure except the presence of conduct disorder (CD) symptoms and diagnoses. Children with ADHD and ID had higher rates of both . Furthermore, children with ADHD and ID had significantly higher rates of oppositional defiant disorder  and CD  symptoms and a higher incidence of oppositional defiant disorder diagnoses  compared with children with ID without ADHD.Children with ADHD and mild ID appear to be clinically typical of children with ADHD except for more conduct problems. This finding has implications for clinicians treating these children in terms of acknowledging the presence and impact of ADHD symptoms above and beyond ID and dealing with a comorbid CD. Attention deficit hyperactivity disorder (ADHD) is a disabling condition, affecting 1.4%-6% of children.It has been suggested that ADHD does not occur in children with ID, and that any inappropriate behavior in children with ID is secondary to “mental impairment.”A population-based study estimating the prevalence of psychiatric diagnoses in children with ID identified hyperkinetic disorder as the most common psychiatric disorder.In the present study, we compared the rates of comorbid problems and ADHD symptom levels in 2 groups of children with ADHD, 1 group with ID (ADHD + ID group) and the other group without ID (ADHD-only group). Consistent with previous studies of ADHD, we defined ID is an IQ test score <70. We hypothesized that the ADHD profiles in the 2 groups (ADHD + ID [IQ <70] vs ADHD-only [IQ ≥70]) would be highly similar in terms of symptoms, rates of subtypes, and patterns of comorbid problems .International Statistical Classification of Diseases and Related Health Problems, 10th revisionDiagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV)Participants were recruited from more than 30 child and adolescent mental health services or community pediatric outpatient clinics in Wales, England, and Scotland for a genetic study of ADHD. Given this study's focus on evaluating for the presence of nonsyndromal ID in children with ADHD, Diagnostic and Statistical Manual of Mental Disorders, 3rd edition revised (DSM-III-R)A total of 971 children met the inclusion criteria and had sufficient data for analysis. All of these children met the DSM-IVthe Wechsler Intelligence Scale for Children versions III (n = 381) and IV (n = 590)International Statistical Classification of Diseases and Related Health Problems, 10th revision and DSM-IV criteria, children with an IQ score of 50-69 were considered to have mild mental retardation/ID and classified in the ADHD + ID group. Children with an IQ score ≥70 were classified in the ADHD-only group.Cognitive ability was assessed using ADHD symptoms, impairment, and diagnoses were confirmed using the Child and Adolescent Psychiatry Assessment (CAPA),The CAPA was also used to assess current symptoms, impairment, and DSM-IV diagnoses of comorbid oppositional defiant disorder (ODD), CD, anxiety disorders , depression, and mania. Comorbid symptoms were also assessed using the child version of the CAPAWechsler Intelligence Scale for Children version III.To compare clinical variables found to be associated in the primary analysis in the ADHD + ID and ADHD-only groups, we turned to the Avon Longitudinal Study of Parents and Children (ALSPAC), a large, well-characterized longitudinal dataset. Details of the study methodology are available elsewhere.The ADHD clinical sample was divided into those with ID  and those without ID . The 2 groups were compared on each of the clinical factors identified. All descriptive statistics are presented as raw scores for ease of interpretation. Where a variable was nonnormally distributed, the scores were naturally logarithmically transformed, and analyses were run on transformed scores.P = .003 (0.05/15) for the 15 tests performed.Clinical predictor variables were used to predict binary outcomes (ADHD + ID or ADHD-only) using regression analyses. All analyses included child's age at the time of assessment as a covariate. Sex was not included as a covariate, because it was not associated with the presence or absence of ID. Clinical variables were assessed both categorically and continuously, whenever relevant. All analyses were performed using SPSS version 16 . To take into account multiple testing, Bonferroni correction for the number of variables tested was used, α was set at Based on our results, a hypothesis-driven comparison of the ADHD + ID and ID-only samples was performed for rates of diagnoses and symptom counts for ODD and CD, adjusted for the covariates age, sex, and IQ. CD items available in both datasets were summed and used to generate the CD diagnoses .At the time of assessment, 74.3% of the children (n = 721) met the criteria for DSM-IV ADHD Combined type, 6.0% (n = 58) met the criteria for DSM-IV ADHD Inattentive type, 9.6% (n = 93) met the criteria for DSM-IV ADHD Hyperactive-Impulsive type, and the remaining 10.2% (n = 99) met the criteria for DSM-III-R ADHD. The rates of comorbid disorders were 45.2% (n = 435) for DSM-IV ODD, 17.6% (n = 171) for DSM-IV CD, 6.1% (n = 59) for any anxiety disorder, and 1.1% (n = 11) for any depressive disorder. The mean IQ test scores were 61.8 ± 5.4 for the ADHD + ID group and 87.8 ± 11.4 for the ADHD-only group; the range of scores was 50-69 for the ADHD + ID group and 70-139 for the ADHD-only group. The scores were normally distributed for the sample as a whole.The mean IQ score of the ID-only group was 64.8 ± 4.5. At the 128-month assessment, 2 of the children in the ID-only group met the criteria for DSM-IV ODD (3.4%), and none met the criteria for DSM-IV CD.The ADHD + ID group was older than the ADHD-only group, but the 2 groups did not differ in terms of sex distribution. P = .001). After adjusting for sex, age, and IQ score, the children in the ADHD + ID group were significantly more likely to have a diagnosis of ODD, and had significantly more symptoms of ODD and CD. Statistical assessment of the between-group difference in the rate of CD diagnoses was not possible, given the rate of 0 in the ID-only group.Results of the comparison of ADHD + ID and ID-only groups  are presented in www.jpeds.com).In our clinical sample of children with ADHD, those with and without mild ID (IQ score 50-69) exhibited similar patterns of ADHD subtypes, total number of ADHD symptoms, and comorbidity with ODD, anxiety, and depression. The children in the ADHD + ID group did have higher rates of CD symptoms and diagnoses, however. To explore these results further and test whether these differences were related to an increase in behavioral problems in children with ID in general, we compared our ADHD + ID group with a population-based sample of children with ID but without ADHD. We found significantly higher rates of ODD diagnoses and ODD and CD symptoms in the ADHD + ID group, suggesting that the combination of ADHD and ID results in increases in the rates of comorbid CD and ODD beyond the rates of these disorders in individuals with ID only or ADHD only. The mean IQ score was lower in the ADHD + ID group compared with the ID-only group. This difference in IQ may be related to selective attrition in the ALSPAC sample,ADHD is one of the most common forms of psychopathology in children with ID.Studies with clinic-referred children and community and population samples have shown consistently higher rates of ADHD in children with ID and higher rates of ID in children with ADHD.The few studies examining whether rates of comorbid psychiatric disorders in ADHD differ in children with and without ID have shown mixed results. Some studies have found higher rates of comorbid impairments in social skills, conduct problems, aggression, and noncompliance in children with ADHD and ID compared with children with ADHD and normal IQ.www.jpeds.com).A limitation of previous research is that questionnaires generally have been used to assess comorbidity rather than the more in-depth standardized diagnostic assessment methods used in the present study. Another strength of the present study is the relatively large sample size of the ADHD group compared with previous studies. The IQ cutpoint used to delineate comparison groups in the literature varies, such that in some studies, children with borderline ID (IQ 70-85) are included in the group of children with mild ID. Although the present study focused on comparing children based on an IQ cutpoint of 70, reanalysis of the data after dividing the children into 3 groups  showed a similar pattern of results .Our results, together with other findings, suggest that excluding children with ADHD from services and interventions on the basis of the presence of mild ID is clinically unwarranted, given that children with ADHD and ID do not seem to differ from those without ID in terms of ADHD subtype and number of ADHD symptoms. They are more likely to have CD, however. It also appears that they differ from children with ID alone, suggesting that ID does not drive the link to conduct problems. Thus, services that deal with ADHD should be well placed to manage ADHD in children with mild ID; however, they will need access to the types of social and clinical interventions that will also help manage associated conduct problems.