Objective: Increased vulnerability to extraneous distraction is a key symptom of Attention-Deficit Hyperactivity Disorder (ADHD), which may have particularly disruptive consequences. Here we apply Load Theory of attention to increase understanding of this symptom, and to explore a potential method for ameliorating it. Previous research in nonclinical populations has highlighted increased perceptual load as a means of improving the ability to focus attention and avoid distraction. The present study examines whether adults with ADHD can also benefit from conditions of high perceptual load to improve their focused attention abilities. Method: We tested adults with ADHD and age- and IQ-matched controls on a novel measure of irrelevant distraction under load, designed to parallel the form of distraction that is symptomatic of ADHD. During a letter search task, in which perceptual load was varied through search set size, participants were required to ignore salient yet entirely irrelevant distractors (colorful images of cartoon characters) presented infrequently . Results: The presence of these distractors produced a significantly greater interference effect on the search RTs for the adults with ADHD compared with controls, p = .005, ηp2 = .231. Perceptual load, however, significantly reduced distractor interference for the ADHD group and was as effective in reducing the elevated distractor interference in ADHD as it was for controls. Conclusions: These findings clarify the nature of the attention deficit underlying increased distraction in ADHD, and demonstrate a tangible method for overcoming it. Symptoms of inattention and distractibility are key diagnostic criteria for Attention Deficit Hyperactivity Disorder (ADHD) and appear to form the most pervasive component of the disorder; inattentive symptoms persist into adulthood more commonly than symptoms of hyperactivity-impulsivity . Such syThe present study applies the Load Theory of Attention and Cognitive Control  to enhanIn support of Load Theory are abundant demonstrations that increased perceptual load in the task results in reduced distractor processing throughout visual cortex, leading to reduced distractor interference across a range of distractor types , but instead the extent to which response associations of different distractor stimuli affect the target response. The defining role of distractor–response associations in this measure presents two limitations in indexing irrelevant distraction in ADHD. First, in the light of proposals that disruption to inhibitory mechanisms is one of the deficits underlying ADHD e.g., , it is uIndeed, despite its prevalent use, previous studies of ADHD using variants of the response-competition task have produced somewhat inconsistent results; although some studies find evidence of increased interference in the ADHD group e.g., , others Finally, we note that the majority of previous investigations into attention in ADHD have studied child populations. As both early and late attentional selection processes are subject to significant developmental changes , it is iWe therefore compared the performance of adults with ADHD with that of age-matched control participants on a recently established measure of irrelevant distraction , 2008b, To test our claim that the elevated distraction in ADHD can be ameliorated under conditions of high perceptual load, we manipulated perceptual load by changing the similarity between the target and the other search letters. In the low load condition the other letters were five small ‘o’s, whereas in the high load condition they were five angular letters see . This maThirty-four age-matched adults participated in the study: 17 adults with ADHD and 17 volunteer controls. Participants in the ADHD group were recruited via the Maudsley Hospital Adult ADHD Clinic and local ADHD support groups. All ADHD participants were diagnosed in the U.K. by a psychiatrist who prescribed stimulant medication treatment . The U.K. diagnostic standards are conservative, with the diagnosis requiring evidence of ADHD in childhood and persistence of sufficient symptoms and impairment into adulthood. The standard diagnostic procedure uses a clinical diagnostic interview and detailed developmental account, with informants included if they are available. Fifteen of the ADHD participants were taking prescribed stimulant medication —these participants were tested after a 24-hour medication washout period.Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM–IV) ADHD that symptom occurs is rated as occurring from never or rarely (0) to very often (3). As per the DSM–IV criteria, half of the items relate to inattentive symptoms, and half relate to hyperactive-impulsive symptoms. Scores can be computed using two methods , or current use of psychoactive medication (other than prescribed ADHD medication for the ADHD group). All control participants reported no history of ADHD and reported fewer than the threshold of six symptoms on both the hyperactive-impulsive and inattentive scales of Barkley and Murphy’s Current Symptoms Rating Scale. The data of one control participant were omitted from analysis for having a percentage error rate over three standard deviations greater than the mean among control participants in the high load condition.Control participants were recruited via the University College London volunteer participant pool. Participants were recruited by age, to match the ADHD group. The ADHD and control groups showed similar IQ scores  from a 15 in. monitor. Each trial began with a 500-ms presentation of a fixation cross, immediately followed by a 200-ms presentation of six letters arranged to form a circle  the letter circle display appeared alone. On 10% of trials a distractor cartoon image was presented either above or below the letter circle display, remaining onscreen until the end of the trial. Each trial ended either upon response, or (if no response was made) after 2000 ms. A tone sounded for incorrect or missed responses. Participants completed two blocks of 12 practice trials, followed by eight blocks of 60 trials. Load was manipulated between blocks in the order Low-High-Low-High-Low-High-Low-High or High-Low-High-Low-High-Low-High-Low . The first three trials of each block were treated as warm up trials and never contained a distractor.Mean RTs and percentage error rates were calculated as a function of group and experimental condition see .F = 208.64, MSE = 9665.84, p < .001, ηp2 = .871, 95% CI [212.91–281.57]  = 42.22, MSE = 2355.03, p < .001, ηp2 = .577, 95% CI [36.38–75.01], reflecting significantly slowed RTs in the presence (vs. absence) of the distractor. Critically, there was a significant interaction between group and distractor condition, F = 9.29, p = .005, ηp2 = .231. As can be seen in RTs of less than 100 ms or greater than 1500 ms , and incorrect responses, were excluded from RT analysis. Mixed model ANOVA (group × load × distractor condition) revealed a main effect of load, .57] see , confirmF = 7.94, MSE = 1206.39, p = .008, ηp2 = .204, reflecting that distractor interference was reduced under high load, t(32) = 4.04, SEM = 9.55, p < .001, d = 1.43, 95% CI [19.09–58.00], compared with low load, t(32) = 6.01, SEM = 12.65, p < .001, d = 2.12, 95% CI [47.07–98.62]. Importantly, there was no three-way load × distractor × group interaction, indicating that load was equally effective in decreasing distractor interference for all participants, F < 1, ηp2 = .010.Distractor presence also significantly interacted with load, F = 6.751, MSE = 40635.62, p = .014, ηp2 = .179. However, differences in overall RT did not account for the increased distractor costs. An additional ANOVA on the percentage increase in RT for distractor trials compared with no distractor trials, in high and low load, confirmed significantly greater percentage distractor costs in the ADHD group, F = 7.85, MSE = 105.55, p = .009, ηp2 = .202, 95% CI [1.60–11.46]. It is striking to note that even when baseline RT was controlled for, the distractor costs of the ADHD group were more than twice those seen for control group. Most importantly, however, despite their greatly increased levels of distraction, even when overall RT slowing is accounted for it is clear that the ADHD group were able to benefit from a significant reduction in distraction under high load, t(16) = 3.13, SEM = 3.38, p = .006, d = 1.57, 95% CI [3.412–17.75]. As can be seen in F = 1.12, p > .29, ηp2 = .035). In fact increasing load compensated for the increased distractor costs of the ADHD participants, to the extent that the high load distractor costs of the ADHD group were of a similar level to those experienced by the control group under low load .In keeping with previous findings of slower RTs in ADHD e.g.,  the ADHDr2 = .203, F = 3.83, p = .033 .Finally, we examined the extent to which specific symptoms of ADHD predicted distractor interference. A multiple regression, conducted on inattentive and hyperactive-impulsive Summary Scores for both ADHD and control participants, revealed that inattentive scores alone significantly predicted overall distractor cost see : For theF = 4.28, MSE = 54.03, p = .047, ηp2 = .121, 95% CI [.09–5.28], reflecting more errors in the presence of a distractor. A main effect of load on error rates was also found, F = 58.87, MSE = 105.61, p < .001, ηp2 = .655, 95% CI [9.95–17.78]. There was no interaction between load and distractor presence, although the trend mirrored the pattern found on RTs, F = 1.12, MSE = 29.87, p = .30, ηp2 = .023.Although our use of a RT task, with an emphasis on performance speed, meant that RT was our main measure, the error rates also showed a main effect of distractor presence, F = 6.31, MSE = 205.10, p = .017, ηp2 = .169, 95% CI [1.18–11.35], qualified by a load x group interaction, F = 5.93, p = .021, ηp2 = .160, reflecting more errors among ADHD participants compared with controls, especially under high load. There was no interaction between group and distractor presence, or three-way load × distractor presence × group interaction, Fs < 1, ηp2 = .023 and ηp2 = .022, respectively.A significant main effect of group was found on errors, The present study establishes two key findings: i) Adults with ADHD show more than double the distractor interference compared with controls; the increase in RT in the presence of distractors is more than twice the increase seen in the control group. Furthermore, the difference in distractor costs was retained after controlling for the overall slower RTs seen in the ADHD group. This establishes our task as a sensitive measure of a distraction deficit in adults with ADHD. The magnitude of distractor costs was specifically related to the degree of inattentive symptoms reported, suggesting that our task may provide a valid measure of the ADHD inattentive symptoms related to distractibility. ii) The greater levels of distraction in ADHD can be reduced with higher perceptual load in the task. Indeed, perceptual load was equally effective in reducing distraction for adults with ADHD as it was for controls. This finding points to an intact early selective attention mechanism and suggests that distraction in ADHD results from disruption to later attention mechanisms, such as the efficiency of executive cortical control. As mentioned in the Introduction, Load Theory proposes that high perceptual load can reduce distractor interference simply by filtering distractor stimuli from perception. Efficient cortical executive control is only needed then when this early attentional selection fails. It therefore follows that facilitating early selection with high perceptual load can compensate for late selection/executive control deficits that otherwise lead to increased distraction in ADHD.The load effects we identified may also account for the “hyper-focusing” presentation that has been observed in the clinical picture of ADHD  of ADHD. Our results suggest that by increasing perceptual load, for example in educational material , the levels of distraction in individuals with ADHD could be reduced to nonclinical levels; although note that non-ADHD individuals would also be expected to benefit to an equivalent degree from the use of higher visual load materials.With respect to our first key findings of substantially higher distractor interference effects in adults with ADHD, compared with matched controls, which are correlated with ratings of inattentive symptoms, these suggest our RT interference measure can serve as a distractor assessment tool that provides an objective proxy for less tangible symptoms of inattention, such as failing to give close attention to work, being easily distracted, and engaging in mind-wandering . Several aspects of our task may have increased its applicability to clinical forms of distraction reported in ADHD. Unlike previous paradigms (which have failed to produce consistent evidence of elevated distraction), our paradigm is designed to measure distraction from the presence of distractors that are entirely irrelevant to the task and can therefore generalize across different tasks and contexts see , 2011. IIn addition, our distractors’ potency may have been increased by their high salience, in terms of their visual appearance , cultural meaning, and positive emotional associations . The infrequency of distractor presentation in our task may also play a key role. Notably, similar cartoon characters presented as high-frequency response-competition distractors have previously failed to produce inflated distraction in ADHD . Future We note that, although our sample size had sufficient statistical power to detect group differences in the level of distraction, larger scale studies are required to establish our measure as a valid and reliable distractibility test. In addition, future studies should clarify whether our measure predicts informant ratings of inattentive symptoms as closely as self-ratings. Finally, further investigations are still required to clarify the causes of distractibility in ADHD, including the role of both executive  and nonexecutive  factors .In summary, the present study makes three key contributions to the study of ADHD. Our findings introduce the irrelevant distractor paradigm as an objective and sensitive method for assessing distraction in ADHD. This method should prove useful in future research . In addition, we clarify that increased distraction in ADHD reflects disruption to only one of two mechanisms underlying the avoidance of distraction. Finally, we demonstrate a potentially powerful method for reducing the heightened levels of distraction associated with ADHD, by increasing perceptual load. This finding, with the somewhat counterintuitive implication that increasing, rather than decreasing, the perceptual difficulty of tasks for people with ADHD may in fact facilitate their performance, provides a promising direction for the development of novel interventions to overcome this disruptive component of the inattention of ADHD.


Attention Deficit Hyperactivity Disorder (ADHD) is a common neurodevelopmental disorder characterised by the symptoms of inattention, impulsivity and hyperactivity. ADHD was once perceived as a condition of childhood only; however increasing evidence has highlighted the existence of ADHD in older adolescents and adults. Estimates for the prevalence of ADHD in adults range from 2.5–4%. Few data exist on the prescribing trends of the stimulants methylphenidate and dexamfetamine, and the non-stimulant atomoxetine in the UK. The aim of this study was to investigate the annual prevalence and incidence of pharmacologically treated ADHD in children, adolescents and adults in UK primary care.The Health Improvement Network (THIN) database was used to identify all patients aged over 6 years with a diagnosis of ADHD/hyperkinetic disorder and a prescription for methylphenidate, dexamfetamine or atomoxetine from 2003–2008. Annual prevalence and incidence of pharmacologically treated ADHD were calculated by age category and sex.The source population comprised 3,529,615 patients . A total of 118,929 prescriptions were recorded for the 4,530 patients in the pharmacologically treated ADHD cohort during the 6-year study. Prevalence (per 1000 persons in the mid-year THIN population) increased within each age category from 2003 to 2008 [6–12 years: from 4.8 (95% CI: 4.5–5.1) to 9.2 (95% CI: 8.8–9.6); 13–17 years: from 3.6 (95% CI: 3.3–3.9) to 7.4 (95% CI: 7.0–7.8); 18–24 years: from 0.3 (95% CI: 0.2–0.3) to 1.1 (95% CI: 1.0–1.3); 25–45 years: from 0.02 (95% CI: 0.01–0.03) to 0.08 (95% CI: 0.06–0.10); >45 years: from 0.01 (95% CI: 0.00–0.01) to 0.02 (95% CI: 0.01–0.03). Whilst male patients aged 6-12 years had the highest prevalence; the relative increase in prescribing was higher amongst female patients of the same age - the increase in prevalence in females aged 6–12 years was 2.1 fold compared to an increase of 1.9 fold for their male counterparts. Prevalence of treated ADHD decreased with increasing age. Incidence (per 1000 persons at risk in the mid-year THIN population) was highest for children aged 6–12 years.A trend of increasing prescribing prevalence of ADHD drug treatment was observed over the period 2003–2008. Prevalence of prescribing to adult patients increased; however the numbers treated are much lower than published estimates of the prevalence of ADHD. This study has added to the limited knowledge on ADHD prescribing in primary care, particularly in the area of drug treatment in adulthood. Attention Deficit Hyperactivity Disorder (ADHD) is a common neurodevelopmental disorder characterised by the symptoms of inattention, impulsivity and hyperactivity. The prevalence of ADHD in school-aged children and adolescents in the United Kingdom (UK) using the broader Diagnostic and Statistical Manual of Mental Disorders, 4th Edition (DSM-IV) criteria is estimated at 5% . The preADHD/HKD affects children and adolescents in various ways and to different extents; however the consequences of the condition generally impact greatly on patients, their families and those around them. Untreated ADHD/HKD is frequently associated with underachievement in school, harm to relationships with family, teachers and friends, increased rates of criminality and accidents; and the development of comorbid psychiatric symptoms including oppositionality, anxiety, depression and substance misuse ,4.Treatments and interventions for ADHD/HKD are varied and include in the main, psychological therapies and pharmacological treatment . When drOnly one previous study known to us has estimated incidence rates and the prevalence for pharmacologically treated ADHD in boys aged 5–14 years in the UK from 1996–2001 . This stADHD/HKD was once perceived as a condition of childhood only; however an increase in the evidence has highlighted the existence of ADHD/HKD in older adolescents and adults . EstimatCurrently, in the UK, Concerta® XL (prolonged-release MPH) is the only stimulant which has a license for use in the treatment of ADHD/HKD in adults, and only as a continuation treatment in patients whose symptoms have persisted from adolescence into adulthood and have shown clear benefit from treatment . The nonWhile it is recognised that the use of medications to treat childhood ADHD/HKD has increased in the last decade or so, which may be coincident with the publication of the NICE Technology Appraisal on methylphenidate in 2000 , there aA retrospective cohort study was performed using data from The Health Improvement Network (THIN). THIN contains anonymised computerised information entered by general practitioners (GPs) in the UK. With coverage of approximately 5.7% of the UK population 2009), practices that use the database are broadly representative of practices in the UK for patients’ characteristics . GPs par09, practWe identified all individuals who were aged 6 years and over and were registered with a GP practice on the THIN database between January 1, 2003 and December 31, 2008 (the study period). Age of individuals on the THIN database is calculated from the month and year of birth up to the age of 15 years. Once individuals reach the age of 15 years, age is calculated using the year of birth only (i.e. 1st January of that year).The ‘start date’ for these individuals was calculated from the latest of three dates: the date they registered with the GP practice, the date the GP practice started to use the Vision practice system or the date of the practice’s Acceptable Mortality Reporting, used as a quality indicator for the practice. This information was obtained from patients’ records on THIN. This ‘start date’ could precede the start of the study period or could occur during the study period. Individuals were only included in the source population if they had an observation period of at least 12 months from their ‘start date’ and were registered during the study period.The pharmacologically treated ADHD cohort comprised patients with both a prescription coded for a study drug during the study period and a diagnosis of ADHD coded at any time on the database (identified from Read codes). As THIN is a patient-records database, there is no requirement to have diagnoses coded every year. Therefore no time restriction was placed on when the diagnosis was recorded in relation to when the study drugs were prescribed. These patients were identified by examining the records of all individuals in the source population after each patient’s ‘start date’. The final pharmacologically treated ADHD cohort comprised 4,530 individuals.The annual prevalence of pharmacologically treated ADHD was calculated by summing all patients with ADHD and a prescription for MPH, DEX or ATM (the study drugs) in a particular study year. This number was divided by the total number of individuals in the mid-year (1st July) source population in that calendar year. The annual prevalence was expressed per 1000 patients. Age-specific and sex-specific prevalences were calculated.The first 12 months following the patient’s ‘start date’ was used as a screening period. If the first prescription for MPH, DEX or ATM was identified during this 12-month screening period, it was not treated as the incident prescription. Patients prescribed ADHD drugs during this 12-month screening period were not included in the risk pool. Incident prescriptions were defined as a first prescription identified after this 12-month ‘screening period’ and hence the patient was identified as an incident patient during the year in which the first prescription was identified. Only those patients defined as incident patients during the study period were included in the numerator of this study.The denominator comprised individuals from the source population who were considered ‘at risk’ i.e. did not have a diagnosis of ADHD and a prescription for a study drug. Therefore, individuals’ data contributed to the denominator only after the first 12-month screening period following their ‘start date’. Patients who were prescribed ADHD medication before the study period were excluded from the denominator during the study period. Likewise, patients who were prescribed ADHD medications during the study period were excluded from the incidence denominator of subsequent years.Annual incidence was calculated by dividing the number of incident patients by the total number of persons in the source population ‘at risk’ in the mid-year (1st July) population.Prevalence and incidence were calculated for each year of the study period 2003–2008 and stratified into different age bands . No formal comparative statistical analyses were performed.Data manipulation and analysis were conducted using Stata/MP version 11.0 .Ethical approval for this study was granted by the Cambridgeshire 4 Research Ethics Committee (ref: 09/H0305/81).The source population comprised 3,529,615 patients . A total of 118,929 prescriptions were recorded for the 4,530 patients aged ≥ 6 years in the pharmacologically treated ADHD cohort during the 6-year study period with a median number of prescriptions per patient of 17 . The average length of time that the 4,530 patients were registered on the database was 8.5 years . MPH was the drug most frequently prescribed during the study period followed by ATM and DEX . A total of 2,343 patients were incident during the study period. Incidence of prescribing is illustrated in Figure 9.3% maleIn this study, estimates for the prevalence of MPH, DEX and ATM prescribing were calculated for the period, 2003 to 2008, using data from THIN database. It was observed that prevalence of prescribing increased over this time, with a ~2-fold increase for children and adolescents, and a 4–5-fold increase for adults. Incidence of prescribing showed similar patterns whereby the incidence of prescribing was greater in children and declined in adulthood.Overall, prevalence increased over the study period from 4.83 to 9.18 per 1000 patients aged 6–12 years. The highest prevalence of prescribing in this study was to boys aged 6–12 years (15.32 per 1000 boys aged 6–12 years in 2008). Prescribing to male patients in this age category was higher than to female patients . These findings are in line with figures reported in the literature, which report differences in prescribing between the genders ranging from a ratio of 2:1 to 9 . It is nTreatment prevalence for adolescents aged 13–17 years followed a similar pattern whereby the overall prevalence doubled over the study period. The driver of this increase was prescribing to adolescent girls (3.15 increase over the 6 year period) although actual prevalence was again higher in male patients.To our knowledge, only one previous study has examined the use of these drugs in children in the UK . The autA study from the Netherlands used computerised pharmacy dispensing records to examine the prevalence and incidence of psychotropic medications in Dutch children from 1995 to 1999. The highest prevalence was seen in children aged 5–9 years which, in 1999, was 13.9 per 1000 children . More reA study examining prescribing trends for stimulants from 1992 to 1998 using North Carolina Medicaid prescription claim files reported an increase in prevalence from 44 per 1000 patients in 1992 to 95 per 1000 patients in 1998 in children aged 6–14 years. The authors of this paper acknowledged that the rates observed in their study were much higher than other studies reported; however they do not speculate as to why this is the case .More recent studies from the US include a study by Zuvekas et al. who used the Medical Expenditure Panel Survey database to report prevalence of stimulant use from 1997 to 2002 in children aged less than 19 years . The preThese utilisation studies suggest that especially in the US, the prevalence of stimulant use increased substantially during the last decade.The current study has demonstrated a trend of increasing prevalence of pharmacological treatments in the UK, throughout the study period; however the highest prevalence figure reported of 15.4 per 1000 male patients aged 6–12 years is in line with or below those reported in both the Netherlands and the US.More importantly this figure is also lower than the global prevalence of ADHD in children or that of hyperkinetic disorders in the UK, which were recently estimated to be 5% and 1.5% respectively ,27. ThisPopulation surveys in adult populations estimate the prevalence of ADHD in adults to be between 2.5 and 4% -10. WhilA significant strength of the study was the use of a large database such as THIN which provided primary care data on a cohort of over 4500 patients. THIN has been used widely in epidemiological research, including studies on mental health ,29. The A limitation of the data is that detailed information on the diagnoses was not readily accessible; therefore it was not possible to determine the severity of ADHD in the patients identified. An inclusion criterion for the study was that patients were required to be registered on the database during the study period 2003–2008 and have a minimum of one year of registration on the database. However, patients may have registered on the database at various points during this period or before this period. Therefore, the amount of follow-up time for patients registered later on the database may have been less than those registered earlier in the study period. For incidence calculations, patients prescribed ADHD drugs during this 12-month screening period were not included in the risk pool for subsequent years of the study. This resulted in varying look-back periods, in that in 2003, patients incident in 2002 were removed, whereas in 2008, six years of incident patients were removed. However, as the numbers of incident patients are small relative to the denominator, it is unlikely that this would influence reported rates significantly. A potential bias in the data when comparing prevalence between 2003 and 2008 is that some patients may contribute data in both years. Data from such patients would not contribute to the change in prevalence. This potential overlap in the cohorts was not taken into account when comparing the prevalence between 2003 and 2008.http://adhd-adduce.org), as part of the Seventh Framework Programme for Research and Technological Development, to examine the long-term safety of stimulants.The issue of over-prescribing of ADHD medicines was outside the remit of this study, as studies which have looked at this question have identified patients with an ADHD diagnosis who do and do not receive medication and/or psychological treatments, along with patients who receive medication but who do not meet the diagnostic criteria for ADHD ,31. The Epidemiological data from the THIN database revealed a trend of increasing prescribing prevalence of ADHD drug treatment over the period 2003–2008 overall and for all age groups. Whilst male patients aged 6–12 years had the highest prevalence, the relative increase in prescribing was higher amongst female patients of the same age. Prevalence of prescribing of ADHD drugs to adult patients increased over the six-year period; however the numbers remain much lower than the published estimates of the prevalence of the condition. Of the three study drugs, MPH had the highest prevalence, followed by ATM. DEX use in children declined over the study period. Incidence of ADHD drug prescribing was very low across all age categories.This study has added to the existing knowledge on ADHD prescribing patterns in primary care; in particular to the area of ADHD drug treatment in adulthood.LW and MM declare that they have no competing interests. SM received research funding as a result of involvement in this research study. PH is an employee and stock holder of Shire Pharmaceuticals. Shire Pharmaceuticals develops and manufactures drugs to treat ADHD. PA has acted in an advisory role for Shire, Janssen-Cilag, Eli Lilly and Flynn Pharma. He has received education or research grants from Shire, Janssen-Cilag and Eli-Lilly. He has given talks at educational events sponsored by the above companies. ICKW was a member of National Institute for Health and Clinical Excellence (NICE) ADHD Guideline Group and British Association for Psychopharmacology ADHD guideline group. ICKW has received research grants from various pharmaceutical companies; including Shire Pharmaceuticals. He has given talks at educational events sponsored by Janssen-Cilag and Eli-Lilly and acted as an advisor to Shire.SM carried out the data analysis, interpretation and drafted the manuscript. LW contributed to the data analysis and interpretation; assisted with drafting the manuscript; reviewed the final manuscript. MM contributed to the study design, initial data analysis and review of the manuscript. PH conceived the need for the study, participated in the study design, and development of the manuscript. PA contributed to initiating the project, conceiving the study and study questions and review and write up of the paper. IW contributed to initiating the study, conceiving the study and study questions, and also review and write-up of the manuscript. All authors read and approved the final manuscript.The pre-publication history for this paper can be accessed here:http://www.biomedcentral.com/1471-2431/12/78/prepub


Attention-Deficit/Hyperactivity Disorder is not a single pathophysiological entity and appears to have a complex etiology. There are multiple genetic and environmental risk factors with small individual effect that act in concert to create a spectrum of neurobiological liability. Structural imaging studies show that brains of children with Attention-Deficit/Hyperactivity Disorder are significantly smaller than unaffected controls. The prefrontal cortex, basal ganglia and cerebellum are differentially affected and evidence indicating reduced connectivity in white matter tracts in key brain areas is emerging. Genetic, pharmacological, imaging, and animal models highlight the important role of dopamine dysregulation in the neurobiology of Attention-Deficit/Hyperactivity Disorder. To date, stimulants are the most effective psychopharmacological treatments available for Attention-Deficit/Hyperactivity Disorder. Currently only immediate release methylphenidate and atomoxetine are approved for the treatment of ADHD in Italy. Drug treatment should always be part of a comprehensive plan that includes psychosocial, behavioural and educational advice and interventions. Attention-Deficit/Hyperactivity Disorder (ADHD) is a common, long-lasting, treatable childhood psychiatric disorder, characterised by a pattern of developmentally inappropriate inattention, motor restlessness, and impulsivity that affects approximately 3-7% of school-aged children .ADHD was first recognised 100 years ago as a childhood disorder found mainly in boys, and was initially described as "hyperactivity" or "hyperkinetic disorder of childhood". This abnormal behaviour was found to be the result of a biological condition rather than a result of poor parenting . In the The renaming of the disorder, the subsequent focus on attention, and the clarification of three subtypes led to a range of neurocognitive and neurobiological hypotheses regarding the etiology and pathophysiology of ADHD within a more specific brain localisation. Furthermore, neurocognitive models of ADHD have become more refined, and one particular executive process, inhibition, is now considered to be a core deficit .Current theories emphasise the central role of attentional and executive dysfunctions in children ,8, as weRecently, neuroimaging has led to several important advances in the understanding of the neurobiology underlying the clinical picture of ADHD, and demonstrates a clear brain basis to the disorder in regions involved in attention, and executive and inhibitory control ,16. FurtADHD is not a single pathophysiological entity and appears to have a complex etiology. Multiple genetic and environmental factors act together to create a spectrum of neurobiological liability.Genetic factors are implicated in ADHD, but the mechanism of action is not completely understood. Twin, family and adoption studies of ADHD have supported a strong genetic contribution to the disorder, with heritability ranging from 60-90% ,19.Genes regulating neurotransmitter systems have been implicated in ADHD. Candidate gene studies of ADHD have produced substantial evidence implicating several genes in the etiology of the disorder, with meta-analyses supportive of a role of the genes coding for DRD4, DRD5, SLC6A3, SNAP-25, and HTR1B . Genome Sometimes ADHD-like symptoms are exhibited by patients with established neurogenetic disorders such as Tuberous Sclerosis Complex, Neurofibromatosis I, Turner Syndrome, Williams Syndrome, Velocardiofacial syndrome, Prader-Willy syndrome, and Fragile × Syndrome. Although each syndrome may arise from different genetic abnormalities with multiple molecular functions, the effects of these abnormalities may give rise to common effects downstream in the biological pathways or neural circuits, resulting in the presentation of ADHD symptoms .Pre-, peri- and postnatal environmental factors play an important role in the pathogenesis of ADHD. Prenatal factors are associated with maternal lifestyle during pregnancy. For example, prenatal alcohol exposure is known to induce brain structural anomalies, especially in the cerebellum . ChildrePeri-natal factors have also been implicated, with a two-fold increase in ADHD in very low-birthweight children and an increased rate of pregnancy and birth complications in mothers of children later diagnosed with ADHD .Among postnatal factors, a role for malnutrition and dietary deficiency in ADHD has been proposed. An imbalance of essential fatty acid (omega-3 and omega-6) intake has been suggested to be potentially involved in the development of ADHD , althougMore complex models of the etiology of ADHD incorporating gene-environment interplay need to be considered. Recent studies have focused on the joint effects of gene variants (of DRD4 and DAT1) and prenatal substance exposures on subtypes of ADHD children, demonstrating that smoking during pregnancy is associated with the combined ADHD type in genetically susceptible children . A signiGrowing evidence points to the involvement of the frontostriatal network as a likely contributor to the pathophysiology of ADHD. This network involves the lateral prefrontal cortex, the dorsal anterior cingulate cortex, and the caudate nucleus and putamen. In ADHD patients, reductions in volume have been observed in total cerebral volume, the prefrontal cortex, the basal ganglia (striatum), the dorsal anterior cingulate cortex, the corpus callosum and the cerebellum . A develet al. (2008) found WM abnormalities in several distinct regions underlying the inferior parietal, occipito-parietal, inferior frontal, and inferior temporal cortex [Neuroimaging studies have also reported reduced white matter (WM) volumes , midsagil cortex . Tractogl cortex .in vivo. DTI studies have revealed developmental changes in cortical WM pathways in prefrontal regions and in pathways surrounding the basal ganglia and cerebellum in patients with ADHD, which presumably reflect decreasing myelination of axons. It is believed that these changes cause a decrease in the speed of neuronal communication [Diffusion tensor imaging (DTI) is an MRI modality that provides information about the direction and integrity of neural fibre tracks in the brain nication . Moreovenication .As well as offering new data to map the brain systems involved in ADHD, and to integrate these findings with clinical symptoms, functional neuroimaging studies allow us to understand the mechanisms of treatment response ,49. PosiClinical presentation of ADHD may vary according to age and stage of development and there are cultural differences in the level of activity and inattention that are regarded as a problem . DiagnosEndophenotypes can be used as trait markers for disease susceptibility, to identify more genetically homogeneous subgroups, to highlight distinct pathophysiological mechanisms or etiological pathways, or to define "spectrum" phenotypes suitable for quantitative trait analyses . CognitiThe co-existence of several other types of psychopathology along with ADHD, such as oppositional defiant disorder, mood and anxiety disorders, learning disorders, tics, and mental retardation, is very common .Before starting treatment, it is important to identify the target outcomes to guide the therapy decision. Drug treatment should be based on a thorough assessment and should always be part of a comprehensive treatment plan that includes psychosocial, behavioural, and educational advice and interventions. Psychotherapy combined with medication may play a role in treating behavioural problems, organisational issues and psychiatric comorbidities . In ItalBehavioural therapy and pharmacological treatment have both been shown to benefit ADHD patients. A longitudinal study of the efficacy of different treatments  showed after 8-year follow-up that all four of the original treatment groups had a similar outcome: all showed improvement in comparison with pretreatment baseline scores, but none demonstrated superiority .in vivo, it specifically increases extracellular levels of DA in the prefrontal cortex but not in the striatum; probably by modulating cortical synaptic DA uptake via the NE transporter [The fronto-subcortical circuits  associated with ADHD are rich in catecholamines, which are involved in the mechanism of action of medications used to treat this disorder. Neuropharmacological studies have provided evidence that ADHD involves dysregulation of both noradrenaline (NE) and DA neurotransmitter systems . MPH trensporter . Dextroansporter . Strong nsporter . Guanfacnsporter . Guanfacnsporter ,66. TablADHD pharmacological therapies are generally well-tolerated Table . HoweverBoth MPH and ATX significantly increase activation in key cortical and subcortical regions subserving attention and executive functions. Therefore, alterations in dopaminergic and noradrenergic function are apparently necessary for the clinical efficacy of pharmacological treatment of ADHD . HoweverConvergent data from neuroimaging, neuropsychology, genetics and neurochemical studies consistently point to the involvement of the frontostriatal network as a likely contributor to the pathophysiology of ADHD. This network involves the lateral prefrontal cortex, the dorsal anterior cingulate cortex and the caudate nucleus and putamen . FunctioProfessor Paolo Curatolo has served as an Advisory Board Member for Eli Lilly and Shire, and has received research grants from Eli Lilly and Shire. The other authors have no conflicts of interest to declare.PC proposed and designed the study, and revised the final draft. EDA and RM reviewed all the relevant articles on the literature, and prepared the first draft under the supervision of Prof. Paolo Curatolo. All authors contributed to the intellectual content and approved the final version.


Aim. To establish the prevalence of restrictive eating problems, the overlap and association with attention-deficit/hyperactivity disorder (ADHD), and autism spectrum disorders (ASD) and to estimate the heritability of eating problems in a general population sample of twins aged 9 and 12. Methods. Parents of all Swedish 9- and 12-year-old twin pairs born between 1993 and 1998  were interviewed regarding symptoms of ADHD, ASD, and eating problems (EAT-P). Intraclass correlations and structural equation modelling were used for evaluating the influence of genetic and environmental factors. Cross-twin, cross-trait correlations were used to indicate a possible overlap between conditions. Results. The prevalence of eating problems was 0.6% in the study population and was significantly higher in children with ADHD and/or ASD. Among children with eating problems, 40% were screened positive for ADHD and/or ASD. Social interaction problems were strongly associated with EAT-P in girls, and impulsivity and activity problems with EAT-P in boys. The cross-twin, cross-trait correlations suggested low correlations between EAT-P and ADHD or EAT-P and ASD. Genetic effects accounted for 44% of the variation in liability for eating problems. Conclusions. In the group with eating problems, there was a clear overrepresentation of individuals with ADHD and/or ASD symptoms. In typically developing younger children, the prevalence of the clinical eating disorders is low , 2, withDieting as a general, non-specific risk factor increases the risk of developing an eating disorder by about five times . It has Children with early symptomatic neuropsychiatric disorders have been found to have high frequencies of feeding/eating problems , 12 compAs far as we are aware, there are few studies on heritability in prepubertal eating problems/eating disorders. In one study of over 5000 twins aged from 8 to 11 years, parent-reported food neophobia was highly heritable explaining 78% of the variance while 22% was explained by nonshared environmental factors .The present paper assesses the rate of eating problems in a large young cohort of twins from the general population. Results are broken down by gender, genetic background factors, and by validated screening diagnoses of ADHD and ASD. In addition, we examined which facets of ADHD and ASD that had the strongest associations with eating problems.The Child and Adolescent Twin Study in Sweden (CATSS) is an ongoing longitudinal twin study targeting all twins born in Sweden since July 1, 1992. Since 2004, parents of twins are interviewed regarding their children's somatic and mental health and social environments in connection with the children's 9th or 12th birthdays (CATSS-9/12), with an overall response rate of 80% of all families contacted .Parental information on 12,496 children from the birth cohorts between 1993 and 1998 of CATSS was used for analysis. In the present study, 130 individuals were excluded because they had known severe brain damage or known chromosomal aberrations, leaving data on 12,366 individuals (6331 boys and 5996 girls). In a further 62 cases there were missing items on key variables. Therefore in analyses including all key variables 12,304 children (3023 boys and 2852 girls aged 9 and 3296 boys and 3133 girls aged 12) were included. All twins participating in the study were screened for possible neurodevelopmental problems using a specially developed inventory, the Autism-Tics, ADHD, and other Comorbidities (A-TAC) inventory, including a previously used algorithm for eating problems and validated algorithms for ADHD and ASD . Diagnostic and Statistical Manual of Mental Disorders, 4th edition [The A-TAC inventory includes questions to investigate child psychiatric problems based on criteria stated in the  edition . The A-T edition , 17. The edition . Items aIn two validation studies , 17 loweModules used in the present study were Concentration and Attention, Impulsiveness and Activity, Language, Social interaction, Flexibility, and Feeding/Eating. Each module starts with a reminder that the questions refer to a lifetime perspective, in comparison to peers, and that the questions addressing specific symptoms or characteristics may be answered by the response categories “no” (score 0), “yes, to some extent” (score 0.5), and “yes” (score 1.0). As alternatives, “do not know” or “do not wish to answer” are given, both of which are coded as “missing.” The Eating module screens for restrictive eating problems. Eating problems “(EAT-P)” was defined here as scoring ≥1.5 on the collapsed score for the two key questions of the Eating module . These qTo investigate the association between the different facets of ADHD: (1) Concentration/Attention and (2) Hyperactivity/Impulsiveness, and ASD: (1) Language, (2) Social interaction, and (3) Flexibility- and EAT-P we used a binary logistic regression response model with data on 12,366 children. To account for the dependency within twin pairs a generalized estimation equation (GEE) model was fitted to the data. All variables were inserted as continuous covariates, except age. In a first step all factors were assessed in a univariate model, and, in a second step, a multivariate model was created that only included significant associations from the univariate model.Twin methodology is based on the comparison of monozygotic and dizygotic twin pairs. Monozygotic twins share all their genes, while dizygotic twins, on average, share 50% of their segregating alleles. This makes it possible to disentangle genetic from environmental components of a trait or condition. In twin methodology, etiological factors are partitioned into genetic (A) factors, shared environmental (C) factors (factors that make the twins more similar), and nonshared environmental factors (E) (factors that make twins dissimilar). Intraclass correlations and standard continuous univariate heritability models were calculated in Mx . We did Zygosity was determined in over 90% of the twins with a panel of 48 single nucleotide polymorphisms or, for those twins where DNA samples were missing, with the help of validated algorithms .n = 11, 024) constituted the comparison group. Of the 12,304 children included in the present study, 903 were screened positive for ADHD only (scoring ≥6.0 in the ADHD and <4.5 in the ASD blocks), 89 were screen positive for ASD only (scoring ≥4.5 in the ASD and <6 in the ADHD blocks), and 288 children were screened positive for both ASD and ADHD. The rest of the children  of the total population of 12,304 children aged 9 and 12, with a close-to-equal distribution between ages, and a predominance of girls (30 boys and 42 girls). In the comparison group of 11,024 children with no ADHD/ASD, there were 43 children with EAT-P  (n = 1280) there were 29 children with EAT-P . The prevalence of EAT-P was significantly higher in the group of children with ADHD and/or ASD compared to the group of children with no ADHD and no ASD (P < 0.001). The highest prevalence of EAT-P was seen in children scoring positive for both ADHD and ASD .The prevalence of EAT-P was low (ls 0.6%) . In the Forty percent of all children who were reported to have EAT-P and 10% of those without EAT-P were screen positive for ADHD and/or ASD, as shown in P < 0.005) for girls, and for boys Impulsiveness/Activity problems , and age 9 years compared to 12 years . Intraclass correlations were at least twice as strong in monozygotic pairs as in dizygotic same-sex pairs, both generally and in each gender separately . GeneticThe prevalence of EAT-P was low (under one per cent) in these cohorts of 9- and 12-year olds. The prevalence of EAT-P was significantly higher in children who also screened positive for ADHD and/or ASD, with the highest prevalence of EAT-P, almost ten percent, reported for girls who screened positive for both ADHD and ASD.Social interaction problems were strongly associated with EAT-P in girls, and impulsivity and activity problems were strongly associated with EAT-P in boys.In childhood, eating problems seemed to be in equal parts accounted for by genetic and nonshared environmental background factors.EAT-P in the present study was defined by parent-reported weight stop/loss combined with fear of gaining weight in the child, and the main findings were as follows.Based on earlier published reports, the low prevalence of restrictive eating in the age cohorts in the present study was to be expected , 5. HoweThe prevalence of EAT-P, at least as defined in this study, was relatively low compared to other developmental problems . SimilarGender specific differences could be seen concerning neurodevelopmental problems associated with EAT-P. Hyperactivity and impaired social interaction showed strong and significant association to EAT-P for both genders. As far as we know it is a new finding for prepubertal eating symptoms, but it would seem to be in agreement with earlier literature on adolescent onset eating disorders –33. HoweEating problems in 9 to 12-year olds appear, similar to later in adolescence , 35, to The strengths and limitations of the study should be taken into account in interpreting findings. The population-based nature of the study sample is an important strength. An obvious limitation is that the information regarding symptoms and behaviour consisted of parent ratings in a telephone interview. The A-TAC inventory has a proven excellent ability to distinguish children with neurodevelopmental problems from children with no such problems , but it The clinical implication of this study is that neurodevelopmental disorders should be considered in children with disordered eating, and, conversely, that eating problems/disorders should be considered in children with ADHD and/or ASD. Interventions must be matched to the patient, and only if neurodevelopmental aspects are considered in each individual case, one can expect results.


Low Birth Weight (LBW) is prevalent in low-income countries. Even though the economic evaluation of interventions to reduce this burden is essential to guide health policies, data on costs associated with LBW are scarce. This study aims to estimate the costs to the health system and to the household and the Disability Adjusted Life Years (DALYs) arising from infant deaths associated with LBW in Southern Mozambique.Costs incurred by the households were collected through exit surveys. Health system costs were gathered from data obtained onsite and from published information. DALYs due to death of LBW babies were based on local estimates of prevalence of LBW (12%), very low birth weight (VLBW) (1%) and of case fatality rates compared to non-LBW weight babies [for LBW (12%) and VLBW (80%)]. Costs associated with LBW excess morbidity were calculated on the incremental number of hospital admissions in LBW babies compared to non-LBW weight babies. Direct and indirect household costs for routine health care were 24.12 US$ . An increase in birth weight of 100 grams would lead to a 53% decrease in these costs. Direct and indirect household costs for hospital admissions were 8.50 US$ . Of the 3,322 live births that occurred in one year in the study area, health system costs associated to LBW  and DALYs were 169,957.61 US$  and 2,746.06, respectively.This first cost evaluation of LBW in a low-income country shows that reducing the prevalence of LBW would translate into important cost savings to the health system and the household. These results are of relevance for similar settings and should serve to promote interventions aimed at improving maternal care. More than twenty million low birth weight (LBW) babies are born every year in low-income countries Increasingly, global efforts are being deployed to improve child survival, a key target of the Millennium Development Goals (MDGs) Estimates of the economic burden of public health problems that represent a huge toll on infant survival, and economic evaluations of effective interventions that improve this survival are crucial to guide health policies The study was approved by the National Mozambican Ethics Review Committee and the Hospital Clinic of Barcelona Ethics Review Committee. Written informed consent was obtained from all participants involved in the study.The study was carried out in Manhiça, Maputo Province, a semi-rural area in Southern Mozambique. A Demographic Surveillance System (DSS) is run by the Centro de Investigaçâo em Saúde de Manhiça (CISM) and covers Manhiça town and surrounding villages, the Manhiça study area, with a total population under surveillance of over 80.000 inhabitants, which constitutes about 60% of the population of the Manhiça District. The main economic activities are subsistence farming and sugarcane and fruit processing. Most commercial activities are concentrated along the main road from Maputo to Beira. There are two main towns in the district, Manhiça and Xinavane, but most of the population lives in small dispersed villages. The climate is subtropical with a warm and rainy season between November and April, and a cool and dry season during the rest of the year. Geographical and demographic characteristics of the area have been described elsewhere Adjacent to the CISM is the Manhiça District Hospital (MDH), a 110 bed health facility, which provides preventive and curative services. A round-the-clock hospital-based clinical surveillance system has been operating in the area since 1997 and has been described in detail elsewhere Information on household costs for LBW babies was collected between July and November 2007 at the MDH through exit survey. Two sources of incremental cost were identified for LBW compared to non-LBW weight babies during the first year of life, i.e., costs for routine health care  and costs for excess morbidity . In order to measure costs incurred by the households, caretakers of LBW babies were invited to participate in the survey when leaving the hospital and if informed consent was signed a standardised questionnaire was administered. Additional information on direct cost (care and treatments received) and indirect costs for babies transferred to the Maputo Central Hospital (MCH) was obtained retrospectively through household visits.Information on health provider costs was collected by interviewing clinical staff to illustrate routine health care and resources required to provide necessary health care for LBW babies at the MDH and MCH. Unit costs were obtained from previous estimates and data provided by the administration department of the MDH The routine health care that LBW babies receive in Mozambique (as recommended by the WHO) depends on their weight at birth and lasts until the infant's weight reaches 2.5 kg The unit of analysis of costs associated with routine health care was the LBW baby. Costs associated with health care received until a baby reaches 2.5 kg of weight, were estimated Both for routine health care  and excess morbidity , direct and indirect costs for LBW were estimated. Direct costs included: transportation to and from the health facility, expenses incurred while staying at the hospital , other travel cost incurred by caretakers while the baby was admitted to hospital, as well as accommodation costs for nights spent away from home. A fixed user fee of 0.15 US$ was paid by families to the MDH. Iron and multivitamin supplementation were given for free at the pharmacy of the MDH. No transportation costs to and from the hospital due to the delivery were included. Incremental costs of admission after hospital delivery were considered to be zero if the LBW baby was admitted at the MDH for just one night, as these costs were assumed to be associated with delivery rather than with LBW itself. The indirect costs calculated were income or welfare losses incurred by caretakers because of their children's need for care. Self-reported income losses, experienced by caretakers with a formal and remunerated occupation, were included in the analysis. On the other hand, welfare losses borne by caretakers without a formal and remunerated occupation (housewives) were conservatively estimated by multiplying the amount of time spent away from their main activity because of child's illness times the average national minimum statutory monthly wage in force in Mozambique at the time of the study (37 US$) Costs to the health system arising from routine care provided to LBW babies were calculated with reference to a target of 1000 live births at the MDH, assuming 12% and 1% of LBW and VLBW respectively in the area  was carried out to allow for uncertainty around cost estimates  and 2. AThe relationship between total household cost and birthweight was estimated using a log-linear regression model. The dependent variable was the logarithm of total household cost associated with routine health care until an infant reaches 2.5 kg. Logarithmic transformation of costs was carried out because of distribution skewness Poisson regression model was used to quantify the incremental number of visits or admissions experienced by LBW compared to non-LBW weight babies only after assessing their statistical significance.DALYs due to premature death were calculated both for a target of 1000 live births and for the number of live births occurred in the area during the year 2007. It was estimated that out of 1000 babies born in Manhiça, 120 are LBW, and of these, 10 are VLBW. The case fatality rates for LBW and for VLBW compared to non-LBW weight babies during the first year of life were estimated to be 12% and 80%, respectively  Fifty five caretakers of LBW babies were interviewed after hospital delivery, and another 32 at attendance to the routine weighing visit . Mean biThe mean value of household cost, both direct and indirect, associated with routine health care for a LBW baby was 23.04 US$. The distribution of household cost was positively skewed with a median value of 4.06 US$, and minimum and maximum values of 0.19 and 156.86 US$, respectively . The maxLog (household costs) = 13.58–5.30*weight at birth. The results of the regression analysis suggest that an increase of 100 gr in the average weight at birth of a LBW baby would result in a reduction of 53% of the average cost to the household derived from routine health care.The association between household costs for routine health care and weight at birth is represented by the following equation: 2(17) = 11.00; p = 0.856]. Including deaths, the percentage of outpatient attendance was 92.44% for non-LBW weigh babies and 84.6% for LBW babies . However, the number of hospital admissions differed significantly between LBW and non-LBW weight babies. Excluding deaths, 21.3% of non-LBW weight babies and 34.4% of LBW babies were admitted at least once . Including deaths, this percentage was 23.5% for non-LBW weigh babies and 37.6% for LBW babies . LBW babies were expected to have a rate of hospital admissions during the first year of life 1.52 times greater than non-LBW babies (p = 0.007). Incremental costs associated with excess morbidity were thus calculated only on hospital admissions, based on one additional episode of admission for LBW compared to non-LBW weight babies. Incremental costs to the households due to hospital admission during the first year of life were 8.50 US$  of which 75% were indirect costs , and of these 117 were LBW babies (12%) ct costs .Based on Monte Carlo simulations, the total estimated health system costs for routine health care of LBW babies for a target of 1000 babies born in Manhiça, of which 120 were LBW and of these 10 were VLBW, were 50,953.68 US$  . IncremeApplied to the target population of 1000 newborns considered in the analysis, it was estimated that 8 out of 10 VLBW and 17 out of 110 LBW would die during the first year of life. The overall DALYs due to death during infancy due to LBW were 826.63, of which 257.44 are attributable to VLBW babies. Considering 3,322 live births, the overall DALYs due to LBW in the study area were 2,746.06.To our knowledge, this is the first economic evaluation of the costs associated with LBW in rural areas of low-income countries, and shows that LBW carries a significant economic burden both for the health system as well as for the families.Health system costs during infancy associated with LBW babies among the 3,322 live births occurred in the study area during the year 2007 were almost 4 times higher than the average yearly national public health expenditure for the Expanded Programme on Immunization budgeted for the period 2007–2012, also calculated for a target of 3,322 live births While incremental costs associated with LBW were presented for two cohorts of 1000 and 3,322 babies, it is important to mention the average costs both per LBW and non-LBW babies. For instance, non-LBW term newborns with an eutocic delivery are admitted less than 24 hours  and DALYs from all neonatal mortality in the area (836.68), it can be estimated that VLBW contributes to more than one third of the burden of neonatal mortality in the area. Thus, any intervention to reduce VLBW would have a significant impact in reducing neonatal mortality. Similarly, any intervention aimed at reducing the incidence of LBW would generate important cost savings to the families and the health system (apart from the benefit to the children themselves). LBW is mainly the consequence of poor maternal health; therefore improving the effectiveness of the already well attended ANC services by avoiding missing opportunities is an essential step to take to reduce the prevalence of LBW Only one previous study in Africa made an assessment of the economic costs associated with LBW Household cost distribution for routine health care appeared positively skewed, with one high value of 156.86 US$ , while the majority of the estimated costs were concentrated around similar lower values. Skewness of cost distribution is a well known issue and both probabilistic sensitivity analysis and logarithmic transformation were used to resolve it The estimated relationship between household costs for routine health care and weight at birth may appear as a tautology as birth weight was the main variable used to estimate household costs. However, the aim of the estimated regression between household costs and weight at birth was not to assess the existence of a relationship but rather to measure, through univariate analysis, the magnitude of such a relationship.As it was done in a previous study, DALYs instead of costs, were used to measure the burden of death of VLBW newborns In this study the evaluation of the economic burden of LBW focus on short term costs and DALYs associated with LBW. In the health economics literature, the long term economic burden is usually measured considering costs associated with the lower educational and productive outcomes that are usually associated with LBW later in life. While some long term LBW costs estimates have been undertaken in high-income countries Even just focusing on short term costs and DALYs, LBW represents an important economic burden that would justify the implementation of measures to reduce its prevalence. Further research, possibly cohort studies, should focus on the long term economic and health impact of LBW in low income areas in which lifelong disabilities are likely to impose a huge toll particularly on the households, as a consequence of fragile health systems lacking appropriate resources to manage chronic health impairments. Further research is also needed to explore intra-country variation of costs and DALYs associated with LBW. Knowledge of such a variation would assist scaling up LBW-related health interventions in the whole country. Although taking into account differences in health system organizations and LBW prevalence, extrapolation of these findings to other Sub-Saharan African countries might be possible for the similar resources available for the treatment and care of LBW babies.


Little is known about the contribution of impulsivity, inattention and comorbid attention deficit/hyperactivity disorder (ADHD) in the development and maintenance of bulimia nervosa (BN). In particular, their specific contribution to disordered eating symptoms and whether they have additive effects to the general psychopathological burden remains unclear.Fifty-seven female patients seeking treatment for BN and 40 healthy controls completed diagnostic questionnaires and interviews that investigated: a) ADHD, b) impulsivity, c) eating disorders and d) general psychopathology. Attentional processes and impulsivity were assessed by a comprehensive computer-based neuropsychological battery.Twenty-one percent of patients with BN met the clinical cut-off for previous childhood ADHD compared to 2.5% of healthy controls. Adult ADHD according to DSM IV was also more prevalent in patients with BN, with an odds ratio of 4.2. Patients with BN and previous childhood ADHD were more impulsive and inattentive than patients with BN alone. These patients also displayed more severely disordered eating patterns and more general psychopathological symptoms compared with those without ADHD. Severity of eating disorder symptoms was better explained by inattentiveness than by either impulsivity or hyperactivity.Our data suggest an elevated rate of former childhood and current ADHD-symptoms in treatment-seeking patients with BN. Stronger impulsivity and inattention associated with more severe neuropsychological deficits and eating disorder symptoms indicate an additive risk that is clinically relevant for these patients. Thus, clinicians should identify comorbid patients who might profit from additional ADHD-specific treatments. Recent evidence suggests that bulimia nervosa (BN) has common clinical features with attention deficit/hyperactivity disorder (ADHD) and furthermore, that ADHD symptoms are more prevalent in patients with BN Patients with BN clinically show increased impulsive behavior such as loss-of-control bingeing and purging Symptoms of BN occur in patients with ADHD with an odds ratio (OR) of up to 3.6 We identified three studies that examined the prevalence of ADHD in people with eating disorders, including one specific to BN. Wentz et al. Given that patients with ADHD and those with BN respond to different pharmacological and non-pharmacological treatments, diagnosing comorbidity might lead to new therapeutic opportunities We examined patients with BN and healthy controls (HC) to determine the severity of their impulsivity and inattention, as well as the rate of childhood and current ADHD symptoms. Furthermore, we measured bulimic symptoms and general psychopathology in our sample to analyze the potential clinical burden of this comorbidity. We hypothesized that patients with BN would display an increased rate of impulsivity, inattention and comorbid ADHD-symptoms compared with the control group. In addition, we expected current comorbid patients and those with BN who had been diagnosed with ADHD as children to be more impulsive, inattentive and severely affected by bulimia and general psychopathology. Finally, we performed a linear regression analysis to investigate the relative contributions of impulsivity, inattentiveness and hyperactivity to the severity of eating disorder symptoms in order to facilitate the identification of patients at especially high risk.2 and SD = 2.7 kg/m2) from inpatient and outpatient admissions at three German university hospitals for child and adolescent psychiatry and psychosomatic medicine for adults  and via an advertisement in the outpatient clinic . None of these patients reported using stimulants or illicit amphetamines at the time of the study. Furthermore, we recruited, via advertisement (without referring to the aims of the study), an age- and IQ-matched control group consisting of 40 women without eating disorders and with normal BMI.We recruited 57 consecutive female patients with BN  = 4.7 years) of average intelligence (mean IQ = 107 and SD = 11.3) and normal body weight  The WRI is a structured 28-question interview that consists of 7 subscales representing 7 psychopathological domains. The interviewer scores global ratings from 0–2 for each psychopathological domain based on the degree of patient impairment and symptom pervasiveness across situations. A psychopathological domain is rated as above threshold only if both ratings average 1 or higher. ADHD is considered present when the inattention and hyperactivity domain, as well as two or more other domain, are above threshold The ADHS-SB consists of 22 questions across three subscales that concern current inattention, hyperactivity and impulsivity with intensity ratings ranging from 0–3. The inattentive subtype is present when at least six inattentive items are rated with scores of two or higher. The hyperactive/impulsive subtype is present when at least six hyperactive/impulsive items are rated with scores of two or higher. An ADHD diagnosis of the combined type is present when both of the above criteria are fulfilled The WURS-K is a 25-item retrospective measure of the ages of 8–10 years. Items are rated from 0–3. When the total score is above 30, there is a 93% sensitivity and 92% specificity for patients to be diagnosed with childhood ADHD To assess impulsivity and attention more objectively, we applied the TAP (Testbatterie zur Aufmerksamkeitsprüfung) - a comprehensive computer-based neuropsychological battery that consists of tests of go/no-go tasks, divided attention and congruent/incongruent executive functions In the Divided Attention task, the participant is presented with visual and auditory stimuli simultaneously. If visual stimuli on a screen form a square or two identical auditory stimuli follow each other, a button-press is required.ould be pressed. For example, an arrow appearing on the right side of the screen and pointing to the right was considered compatible and had to be answered by a right hand button press; a response was incompatible if an arrow on the right side of the screen was pointing to the left.The Compatibility/Non-compatibility test consisted of arrows that pointed left or right and appeared on the left or right side of the screen. The direction of the arrow indicated the hand with which the respective button shThe participants’ reaction times (RTs), the standard deviations (SDs) of RTs and the number of errors or misses committed during the last two subtests were calculated.We administered the Eating Disorders Inventory EDI-II;  and the We used Beck’s Depression Inventory BDI-II, , the depAs symptoms of restless legs syndrome can mimic those of ADHD IQ was measured using the Hamburg Wechsler Intelligence Test (HAWIK-IV) for adolescents and the German “Mehrfach Wortschatz Intelligenz-Test B” (MWT-B) for adults.The 30-item Barratt Impulsiveness Scale (BIS-10) assessed impulsivity We performed all statistical analyses using SPSS/PASW 18.0.We compared patients and healthy controls on measures of age, IQ, EDI-II, BDI and SCL-90. Furthermore, we calculated and compared total scores on the WURS-K, ADHD-SB and WRI, as well as the percentage of BN and HC meeting the criteria/cut-offs. We used the two-tailed Student’s t-test for age and IQ and the Mann-Whitney-U-Test for all other analyses to account for non-normal distributions. Alpha was adjusted for multiple testing for each domain separately .Patients only received the full diagnosis of adult ADHD according to the DSM-IV if they met both childhood and current ADHD criteria. We used the most conservative combination for adult ADHD in our sample, requiring the WURS-K (childhood) the WRI and the ADHD-SB (current) to be above threshold to calculate an ADHD and BN comorbidity rate.Next, we split the BN patients into subgroups: one group with and one group without previous childhood ADHD (WURS-K >30). The patients were placed into subgroups because, as described in the We compared BN-patients with HC and the two subgroups of BN (with former childhood ADHD or without childhood ADHD) using the BIS-10, SIAB-EX, EDI-II, BDI-II, SCL-90 and SCID-I.We transformed the TAP results for the RTs, the SD of RTs and the misses/errors into age and sex-specific T-values based on German norms because we found the raw values to be age-dependent To examine if neuropsychological differences between the respective groups are affected by the presence of depressive and anxious symptoms, we also calculated individual linear regressions with the SCL_anxiety and BDI scores to obtain non-linear residuals. Between-group differences in these residuals where then examined by using the Mann-Whitney-U-Tests as described above.To assess which ADHD symptoms best explained the variance of BN clinical symptoms, a linear regression was performed with the ADHS-SB subscales for impulsivity, inattention and hyperactivity as dependent variables and the SIAB-EX eating pathology total score as independent variable.Patients with BN and HC did not differ with regard to age and IQ; as expected, they did differ significantly with regard to eating disorder characteristics, depression and general psychopathological scores.In patients with BN, the prevalence of former childhood ADHD  was 21.0%  versus 2In the ADHD-SB, which measures current symptoms, 24.5% of patients vs. 5.0% of HC scored above the cutoff (OR 5.3). For subtypes, 5.2% of patients belonged to the inattentive subtype, 12.3% of patients were included in the hyperactive/impulsive subtype and 7.0% of patients were included in the combined subtype. In the expert interview, 19.3% of patients vs. 5.0% of HC were rated above the cutoff value .We found that 10.5% of patients scored above the cutoff on all three ADHD measures (the childhood measure and both current ADHD measures) compared to 2.5% of HCs (OR 4.2). The combination of childhood and current ADHD is required to meet a diagnosis of adult ADHD according to the DSM-IV; participants must show continuous symptoms from childhood to adulthood. Fourteen percent of patients showed current symptoms of ADHD without meeting the childhood-onset criteria. Three quarters of these patients had subthreshold childhood symptoms (WURS-K between 15 and 30).This section compares patients with comorbid BN and previous childhood ADHD to those without childhood ADHD. Patients with BN and childhood ADHD did not differ from those without ADHD in age , IQ  or BMI .As observed in In general, patients with BN and childhood ADHD had a tendency towards lower neuropsychological test scores than those without childhood ADHD indicating more inattentive and impulsive response patterns. Specifically, patients with BN and childhood ADHD showed inconsistent and variable responses in the Divided Attention and Incompatibility task. However, these results did not survive a correction for multiple comparisons.2 = 0.14) as well as the anxiety subscale of the SCL-90 (η2 = 0.24). Although patients comorbid with BN and ADHD had a tendency to be more severely affected across most measures, this result did not hold for lifetime AN, which demonstrated an opposite trend.We found no correlations among psychiatric symptoms and age, IQ or BMI. Inpatients did not score higher on comorbidity or any other psychiatric symptoms compared with outpatients (data not shown).After controlling for the effects of depressive and anxious symptoms for BN vs. HCs, the following group differences remained significant: BIS scales, TAP Go/Nogo standard deviation, EDI total score and SCL-total score; thus, these variables differ between BN and HCs independent from depression and anxiety. For the comparison between BN with and without childhood-onset ADHD, only the TAP Visual Divided Attention standard deviation and Total Compatible/Incompatible standard deviation remained significant; BIS-total score (p = 0.095) and EDI total score (p = 0.090) showed trends towards significance.Patients with comorbid BN and childhood ADHD scored significantly higher on the ADHD-SB subscale for current inattention than those without childhood ADHD . There was a trend towards more current hyperactivity (7.33 vs. 4.50 p = 0.063) and current impulsivity .inattention = 0.323, p<0.001; βhyperactivity = 0.199, p = 0.261; and βimpulsivity = 0.170, p = 0.330). Including impulsivity as measured by the BIS-10 of the model did not significantly increase the total explained variance (39%); moreover, the BIS-10 did not significantly predict eating disorder symptoms . Similar results were obtained when using the EDI-II as a dependent variable (data not shown).When examining which of the ADHD subscales was responsible for most of the variance of eating disorder symptoms, we found that inattention explained more of the variance of eating disorder symptoms than either impulsivity or hyperactivity. Taken together, these subscales explained 36% of the variance of the SIAB-EX eating disorder total score . This rate is much higher than the 2.5% rate found in our control sample, the 2.7% rate found in females worldwide These results fit published results by Yilmaz et al. We examined the subgroup of patients with childhood ADHD because Mikami Our study also confirms more impulsive and inconsistent response patterns for treatment-seeking patients with BN in the neuropsychological test battery. Some previous neuropsychological studies on these patients showed similar impulsive behaviors In addition, we found markedly more eating behavior pathologies in patients with BN and childhood ADHD based on the SIAB-EX total scores compared with patients without ADHD. Patients with BN and ADHD also had significantly more severe psychiatric symptoms  and scored higher on the SCL-90 subscales of depression and anxiety but not amphetamine use. These symptoms are typically found in BN We questioned whether the above effects were due to the greater general psychopathological burden of patients with two diagnoses or whether there is a specific interaction between BN and ADHD. Virtually any illness combination might pose a risk of increased psychosocial stress and additional clinical complications compared with only one diagnosis We analyzed the relative impact of impulsivity, inattention and hyperactivity on the severity of eating disorder symptoms. Inattention in adulthood explained most of the variance within the eating pathology for patients with BN. This study is the first to directly show this relationship. Cortese et al. In summary, we know from previous studies that childhood impulsivity is a significant risk factor for developing BN in adolescence or early adulthood. Our study showed that patients with BN who are more impulsive than average and those who are also more inattentive may be at an even higher risk for severe eating disorders.There are several possible ways in which ADHD and BN might interact. ADHD impulsiveness likely contributes to binge eating and purging Because our study was cross-sectional, we cannot make causal or developmental inferences. In addition, the age range sampled does not allow us to generalize our results to adolescents or adults alone; however, we sampled the most common onset age of BN, which presents an ecologically valid representation of treatment-seeking patients with BN. Treatment-seeking might lead to a higher rate of comorbidity than has been found in population-based samples. To control for this effect, an additional control group, consisting of non-treatment seeking patients with BN would be needed. Within our group, however, inpatients did not report more comorbidities or stronger psychopathologies than outpatients, so there seems to be no overt effect of treatment modality. Nevertheless, the results of our study should only be generalized to treatment-seeking patients with BN. Furthermore, our findings may in part reflect an interaction effect with the consequences of possible substance abuse, which is quite common in BN The strength of this study is that it is a multidimensional assessment. We used several measures of ADHD, impulsivity, inattention, eating disorders and general psychopathology simultaneously. In addition, we combined self-report questionnaires with expert interviews and objective neuropsychological tests. Thus, we obtained valid results for each category to calculate group comparisons and cross-correlations.Because of the high comorbidity between BN and ADHD, as well as the higher burden for patients with this comorbid condition, clinicians should screen patients with BN for ADHD. A combination of self-report questionnaires and semi-structured interviews can diagnose ADHD in patients with BN. Neuropsychological tests can also support the diagnosis. Care should be taken to test for childhood ADHD symptoms to obtain a complete DSM-IV diagnosis; however, the assessment of symptoms that appear before the age of 12 might suffice


In this research, the micellar behavior of a cationic surfactant, cetyl trimethyl ammonium bromide (CTAB) and an nonionic surfactant, polysorbate 20 (Polyoxyethylene (20) sorbitan monolaurate) in different alcohol solutions media was investigated over the temperature range 293.15–313.15 K. The interaction between two surfactants in binary systems can be determined by calculating the values of their β parameters. The critical micelle concentrations (CMC) of the micelles were determined from the surface tension, the conductivity at different temperatures. The CMC behavior of CTAB and polysorbate 20 was analyzed in terms of the effect of temperature and the increase in the alcohol carbon chain. Changes in the critical micelle concentration of mixed surfactant systems of different alcohol solutions were measured. The CMC decreased sharply as the hydrocarbon chain length of the alcohols becomes larger. This shows that the more hydrophobic alcohols are, the more marked a decrease in CMC is observed. The widespread industrial, technological, and domestic applications of surfactants usually involve mixtures. This is often because the materials that are used are impure, but more importantly because different surfactants are often deliberately mixed to provide enhanced performance .It is necessary in most practical applications to choose mixtures of surfactants to conveniently tune the desired properties of the formulation. Mixtures of surface active materials often show synergistic interactions which would be manifested as enhanced surface activity, spreading, wetting, foaming, detergency, and many other phenomena. Mixtures of nonionic surfactants tend to behave ideally while ionic surfactants can exhibit departure from ideality .From a fundamental point of view, the mixtures of ionic–nonionic surfactants are more interesting because they often exhibit a highly nonideal behavior. Adding a nonionic surfactant into an ionic surfactant micelle can reduce the electrostatic repulsions between the charged surfactant heads and greatly facilitate mixed micelle formation. In the literature, it is possible to find data concerning the anionic/nonionic mixtures of two surfactants rather than those of cationic/nonionic ones which are also used in many processes such as detergents for some materials .The concentration of surfactant needed to initiate micelle formation is called the critical micelle concentration (CMC). The value of the CMC can be determined by the change in the physicochemical properties of the surfactant solution as the concentration of the amphiphile is increased –7. Some Surfactants are mostly low-molecular weight compounds, so when dissolved, they form true solutions in concentration ranges below the CMC. Micelles are aggregates of a large number of simple molecules or ions of surfactants , so the resulting size of such structures is in the colloidal range. For this reason the micelle solutions of surfactants are regarded as association colloids. It is essential to employ physical methodologies which are highly sensitive to structural changes for determining the CMC. The existence of CMC indicates aggregation of amphiphilic molecules in solutions. The knowledge of the CMC is important for the calculation of the thermodynamic parameters, which confirms the scientific interest of a precise determination of the CMC . The CMCSince water alcohol-surfactant systems are frequently used as media in the studies of chemical equilibria and reaction rates, it is essential to investigate the effect of the nature of the alkyl groups in the alcohol on the CMC of the surfactants. Addition of alcohols to aqueous solutions of surfactants has allowed the investigation to be made of the effect of hydrophobic interactions on the micellar structure .The effect of the presence of additives on the CMC of surfactants has been widely studied. It is generally accepted that the alcohol binds to the micelle in the surface region, leading to three principal effects: (a) The alcohol molecules intercalate between the surfactants ionic head groups to decrease the micelle surface area per head group and increase the ionization. This effect is correlated with modification of the growth and shape of the micelle. It seems to be a function of the mole fraction of alcohol at the micellar interface but is independent of the type of alcohol. (b) The dielectric constant at the micellar interface decreases probably due to the replacement of water molecules in the interface region by alcohol molecules. (c) The molecular order of the interface region of the micelle changes –16.N,N dimethyl formamide (DMF) solution. These surfactants were chosen because they are widely used and commercially available. Our work essentially involves the determination of the CMC by means of surface tension and conductivity measurements. In the presence of various chain alcohols, the relationships among the CMC, thermodynamic functions, and the alcohol carbon number and concentration in DMF during the micellization process are discussed.The effect of alcohol addition in micellar solutions of various surfactants in aqueous solutions has not been studied on a large scale. The purpose of this work was to study the effects of some long-chain alcohols on the micellization process of sodium dodecyl sulfate (SDS) and sodium laurate (SLA) in Polyoxyethylene (20) sorbitan monolaurate  abbreviated as PS20 in what follows, and cetyl trimethyl ammonium bromide (CTAB) were used as received from Aldrich. Solutions including alcohol of individual surfactants and CTAB and PS20 mixtures at different ratios of CTAB to PS20 were prepared using doubly distilled and deionized water (GFL-2102). The surface tension of water was checked before the solution preparation. All the solutions were measured under the thermostated conditions at 293.15, 298.15, 303.15, 308.15 and 313.15 K with an accuracy of ±0.1 K.−1 at 25 °C. Into several 100-mL beakers, aliquots of a given concentration of cationic surfactants (1 × 10−2 mol/L) were placed, followed by the addition of a given concentration of Tween 20 (1 × 10−2 mol/L). The mixtures were stirred and diluted stepwise with water. These mixtures were kept for 4 h under thermostatted conditions at different temperatures in order to establish equilibrium.Doubly distilled water from an all-glass apparatus was used to prepare all solutions. The surface tension of the water was 72.8 dyne cmγ (mN/m). The measurements of the surface tension of pure water at 298 K were performed to calibrate the tensiometer and to check the cleanliness of the glassware. In all cases, more than 10 successive measurements were carried out, and the standard deviation did not exceed ±0.2 mN/m. The temperature was controlled within ±0.1 K.The surface tensions of aqueous solutions of single and mixed surfactants at various concentrations were measured on the KSV SIGMA 702 ring tensiometer. The value of the surface tension was the average of the three separate measurements. All the measurements were taken at 298 K. The surface tension measurements were made at 298 K under atmospheric pressure by the ring method. The platinum ring was thoroughly cleansed, and flame dried before each measurement. The measurements were taken in such a way that the vertically hung ring was dipped into the liquid to measure its surface tension. It was then subsequently pulled out. The maximum force needed to pull the ring through the interface was then expressed as the surface tension, −1. Accuracy of the measured conductance was within 0.01 μS. The surfactant conductance was measured after thorough mixing and temperature equilibration. The break point in the plot of either the equivalent conductivity versus the square root of the total surfactant concentration or the molar conductivity versus the total surfactant concentration was taken as the CMC at the mole fraction.The conductometric measurements were taken with a Jenway (UK) conductometer using a cell with a cell constant of 0.92 cmThe surface tension of aqueous solutions of single and mixed surfactants at various concentrations were determined using the Du Nouy ring method at constant temperature. The CMC values were determined by break points in the plot of surface tension values against the concentration values. The CMC values were found to be in agreement with the measured solution conductivity and density. The surface tension data show that the value of CMC of a single surfactant did not change within the temperature range of 298–323 K whereas the value of the CMC of mixed surfactants decreases as the temperature rises above 298 K. This is the reason of the selection of a wide concentration range.The break point in the plot of either the equivalent conductivity versus the square root of the total surfactant concentration or the molar conductivity versus the total surfactant concentration was taken as the CMC at the mole fraction.The surface tensions and conductivities were measured as a function of surfactant concentration at 293.15, 298.15, 303.15, 308.15 and 313.15 K. The CMC values of different combinations of the binary (PS20/CTAB) mixtures in different alcohol solutions were determined from the surface tension and conductivity versus surfactant concentration plots, at different temperatures. CMC data are listed in Tables The CMC value of the mixture decreases after the initial addition of PS 20 (nonionic surfactant) indicating slight CMC synergism . The critical micelle concentrations of mixed surfactants are lower than that of sole CTAB and very close to that of pure PS20. In this respect, this experimental results for fresh solutions agrees with those observed by Mata, who found a decrease in the CMC of mixtures with increase in the mole fraction of PS20, however, the CMC of the mixed system at any composition could not be reduced to be lower than that of pure PS20. A similar decrease in CMC was also observed in the mixture of dimeric anionic and nonionic surfactants –19.The hydrophobic effect associated with the hydrophobic moiety of alcohol molecules also favors micellization and increases as the length of the hydrocarbon chain of the alcohol series increases. This explains the increased lowering of the CMC as the number of carbon atoms increases in alcohol series –22.n-propanol, and butanol are reported in Tables The changes in CMC, with increasing addition of methanol, ethanol, For systems containing an identical alcohol concentration at the same temperature, the CMC values decrease as the alcohol carbon number increases. The CMC values decrease as the number of carbon atoms in the hydrophobic group increases. For a given class, the CMC values decrease as the number of carbon atoms in the hydrophobic fragment increases. As shown in Figs. The CMC values of nonionic surfactants depend on the length of both the lipophilic and hydrophilic parts of their molecules. The CMC decreases with increasing length of the hydrophobic moiety for a fixed hydrophilic group. The CMC of nonionic surfactant decreases with decreasing polyoxyethylene content in the molecule. Due to different structural consequences of intermolecular interactions caused by the different chain-lengths of the alcohols the CMC decreases sharply as the hydrocarbon chain length of alcohols becomes larger. Critical micelle concentration decreases as the nonionic surfactant mole fraction number increases. It has been reported that the synergism of solubilization in mixed micelle solutions decreased with increases in the mole fraction of the nonionic surfactant .The interaction between two surfactants in binary systems can be determined by calculating the values of their β parameters as is shown in Table In this research, the micellar behavior of cationic surfactant, cetyl trimethyl ammonium bromide and nonionic surfactant, polyoxyethylene (20) sorbitan monolaurate in different alcohol solutions media was investigated with the help of surface tension and conductivity over the temperature range 293.15–323.15 K. The CMC and of the micelles were determined from the surface tension and the conductivity measurements at different temperatures. The CMC decreased to a certain minimum and then increased with the temperature, displaying a U-shaped behavior. It was observed that by changing the counter ion from methanol to propanol along with the increase in carbon chain, the CMC shows a decrease. In an alcohol series, the hydrophobic character increases as the number of hydroxyl groups increases. The CMC decreases sharply as the hydrocarbon chain length of alcohols becomes larger. It shows that the more hydrophobic alcohols are, the more marked a decrease in CMC is observed.