Search

Background: Triptans are commonly prescribed for migraine, a pain condition that is highly prevalent in women of childbearing age. No prior studies have investigated associations between exposure to triptans during fetal life and risk of externalising and internalising behaviours in children.Methods: This study was set in the Norwegian Mother and Child Cohort study, a prospective birth cohort. A total of 41,173 live, singleton births without major malformations present at 36-month post-partum follow-up were included in this study; 396 used a triptan during pregnancy, 798 used a triptan prior to pregnancy only, 3291 reported migraine without triptan use, and 36,688 reported no history of migraine or triptan use. Marginal structural models were used to analyse the association between timing of triptan exposure and neurodevelopmental outcome.Results: Children exposed to triptans during pregnancy had a 1.39-fold increased risk of externalising behaviours compared with those whose mothers used triptans prior to pregnancy only (95% CI 0.97, 1.97), a 1.36-fold increased risk compared with the unmedicated migraine group (95% CI 1.02, 1.81), and a 1.41-fold increased risk compared with the population comparison group (95% CI 1.08, 1.85). The greatest risk was associated with first trimester exposure (RR 1.77, 95% CI 0.98, 3.14). Risk differences were small, ranging from 3-6%.Conclusions: This study found an increased risk of clinically relevant externalising behaviours in children with prenatal exposure to triptans, and this risk was highest for first trimester exposure. Absolute risks were small, and the results may be due to confounding by underlying migraine severity. [ABSTRACT FROM AUTHOR]

SUMMARY Aims: The main aim of this post hoc analysis was to evaluate whether response to osmotic release oral system (OROS) methylphenidate (OROS-MPH) was moderated by the concomitant use of antidepressants in attention-deficit/hyperactivity disorder (ADHD) adults stabilized on these medicines for the treatment of depression or anxiety disorders, or a history of mood, anxiety, or substance use disorders. Methods: Two hundred and ninety-six subjects were screened for participation; 227 were randomized (112 to OROS-MPH and 115 to placebo), and 223 were analyzed ( N= 109 and N= 114 for OROS-MPH and placebo, respectively). Subjects with anxiety disorders and depression treated with a stable medication regimen of non-MAOI antidepressants or benzodiazepines for at least 3 months could be enrolled in the study. Subjects currently receiving pharmacotherapy for anxiety disorders or depression were required to have Hamilton-Depression and Hamilton-Anxiety rating scales below 15 (mild range). Results: Concomitant antidepressant use at baseline was not associated with ADHD response, OROS-MPH dose, study completion rate, adverse effects, or exacerbation of anxiety/depression. We did find nominally significant evidence that a lifetime history of mood ( P= 0.09) or anxiety ( P= 0.04) disorders was a moderator of ADHD symptoms and that a lifetime history of substance use disorder ( P= 0.02) was a potential moderator of dose at endpoint. Discussion and Conclusions: We found few moderating effects in this large clinical trial of OROS-MPH in adults with ADHD, which supports the robustness of the clinical response to OROS-MPH in adult ADHD despite variable clinical pictures. [ABSTRACT FROM AUTHOR]

SUMMARY Objective: To assess the impact of comorbid autism spectrum disorders (ASD) on the response to second-generation antipsychotics (SGA) in pediatric bipolar disorder (BPD). Methods: Secondary analysis of identically designed 8-week open-label trials of SGA monotherapy (risperidone, olanzapine, quetiapine, ziprasidone, or aripiprazole) in youth with BPD. Results: Of the 151 BPD subjects 15% ( n= 23) met criteria for comorbid ASD. There were no differences in the rate of antimanic response (YMRS change ≥30% or CGI-Improvement ≤2: 65% vs. 69%; P= 0.7) in the presence of comorbid ASD. Conclusion: No difference observed in the rate of antimanic response or tolerability to SGA monotherapy in the presence of ASD comorbidity. [ABSTRACT FROM AUTHOR]

Aim: To evaluate the safety and efficacy of lamotrigine monotherapy as an acute treatment of bipolar mood elevation in children with bipolar spectrum disorders. Method: This was a 12-week, open-label, prospective trial of lamotrigine monotherapy to assess the effectiveness and tolerability of this compound in treating pediatric bipolar disorder. Assessments included the Young Mania Rating Scale (YMRS), Clinical Global Impressions-Improvement scale (CGI-I), Children's Depression Rating Scale (CDRS), and Brief Psychiatric Rating Scale (BPRS). Adverse events were assessed through spontaneous self-reports, vital signs weight monitoring, and laboratory analysis. Results: Thirty-nine children with bipolar disorder (YMRS at entry: 31.6 ± 5.5) were enrolled in the study and 22 (56%) completed the 12-week trial. Lamotrigine was slowly titrated to an average endpoint dose of 160.7 ± 128.3 in subjects <12 years of age (N = 22) and 219.1 ± 172.2 mg/day in children 12–17 years of age (N = 17). Treatment with lamotrigine was associated with statistically significant levels of improvement in mean YMRS scores (−14.9 ± 9.7, P < 0.001) at endpoint. Lamotrigine treatment also resulted in significant improvement in the severity of depressive, attention-deficit/hyperactivity disorder (ADHD), and psychotic symptoms. Lamotrigine was generally well tolerated with marginal increase in body weight (47.0 ± 18.0 kg vs. 47.2 ± 17.9 kg, P= 0.6) and was not associated with abnormal changes in laboratory parameters. Several participants were discontinued due to skin rash; in all cases, the rash resolved shortly after discontinuation of treatment. No patient developed Steven Johnson syndrome. Conclusions: Open-label lamotrigine treatment appears to be beneficial in the treatment of bipolar disorder and associated conditions in children. Future placebo-controlled, double-blind studies are warranted to confirm these findings. [ABSTRACT FROM AUTHOR]

Background: Little is known about the influence of sex on the course of attention-deficit/hyperactivity disorder (ADHD) and its comorbid psychiatric conditions. The purpose of this study was to examine the effect of sex on the course and psychiatric correlates of ADHD from childhood into adolescence. Methods: Two identically designed, longitudinal, case–control family studies of male and female probands with and without ADHD and their siblings were combined. All subjects were blindly assessed with structured diagnostic interviews. Among subjects with a lifetime history of ADHD ( n = 471, mean age 11.5 ± 4.3 years at baseline), we used linear growth curve models to estimate the effect of time on the change in ADHD symptoms, and whether this effect differed by sex. We also we examined the effect of sex on the association between ADHD and the longitudinal progression of comorbid psychopathology using structural equation models. Results: We found no evidence that sex moderated the effect of age on ADHD symptoms; in both genders, age exhibited a similar effect on the decline of ADHD symptoms. However, the female sample demonstrated greater stability in comorbid psychopathology from childhood into adolescence. Furthermore, we found that the stability of comorbid psychopathology in females remained significant after accounting for the correlation between adolescent psychopathology and adolescent ADHD. In males, childhood and adolescent comorbid psychopathology were no longer correlated when adolescent ADHD was taken into account. Conclusions: Our findings indicate that while the course of ADHD across childhood and adolescence did not differ between males and females, patterns of psychiatric comorbidity were conditional on sex. Future studies should explicitly test how sex modifies the associations between ADHD and risk factors and ADHD and associated functional outcomes. [ABSTRACT FROM AUTHOR]

Joshi G, Mick E, Wozniak J, Geller D, Park J, Strauss S, Biederman J. Impact of obsessive-compulsive disorder on the antimanic response to olanzapine therapy in youth with bipolar disorder. Bipolar Disord 2010: 12: 196–204. © 2010 The Authors. Journal compilation © 2010 John Wiley & Sons A/S. Objective: To compare antimanic response to olanzapine therapy in youth with bipolar disorder (BPD) based on the status of comorbidity with obsessive-compulsive disorder (OCD). Methods: Secondary analysis of identically designed 8-week open-label trials of olanzapine therapy in youth with BPD. Severity of mania assessed with the Young Mania Rating Scale (YMRS) and Clinical Global Impression (CGI) scales. Results: Of the 52 BPD subjects (mean age 8.4 ± 3.1 years) enrolled in the olanzapine trials (mean dose 8.5 ± 4.3 mg/day), 39% (n = 20) met criteria for comorbid OCD. Antimanic response in BPD subjects was significantly worse in the presence of comorbid OCD (YMRS mean reduction: −5.9 ± 13.1 versus −13.7 ± 18.8, p = 0.04; ≥ 30% reduction: 25% versus 63%, p = 0.008; CGI-Improvement score ≤ 2: 25% versus 68%, p = 0.003). There was no difference in the rate of dropouts (50% versus 29%, p = 0.2) or adverse effects in BPD subjects with or without comorbid OCD. Conclusions: Less than expected antimanic response to olanzapine therapy in the presence of comorbidity with OCD suggests that OCD is an important functionally impairing psychiatric comorbidity that may impact the efficacy of antimanic agents in youth with BPD. This study is limited by its design of secondary analysis of data from trials of an uncontrolled nature. Further prospective controlled trials are warranted. [ABSTRACT FROM AUTHOR]

Objective: While concordance between mother and child report continues to be the gold standard in the assessment of pediatric bipolar disorder, uncertainty develops when a mother’s report is not endorsed by the youth. To this end we compared discordant (mother positive and youth negative) and concordant (mother and youth positive) cases. Methods: Subjects were 98 adolescents (12–19 years of age) derived from family studies of bipolar disorder in youth who had both self-reported and mother-reported assessments. Comparisons were made between discordant (n = 35) and concordant (n = 59) cases on a wide range of clinical correlates. Results: Mothers in both groups reported similar rates of symptoms of mania and depression. Within the concordant group, mothers and youth reported similar rates of symptoms of mania. There were no differences between the concordant and discordant groups in onset, duration, or impairment of mania, rates of psychiatric hospitalization, cognitive variables, or rates of disorders in family members. Conclusions: The similarities between discordant and concordant reports in symptomatology of mania and depression, rates of comorbidities, treatment needs, and other clinical correlates suggest that a mother-based diagnosis of mania should not be discounted in discrepant cases in which the youth fails to endorse the diagnosis. [ABSTRACT FROM AUTHOR]

Background: A robust and bi-directional comorbidity between attention-deficit/hyperactivity disorder (ADHD) and psychoactive substance use disorder (PSUD, alcohol or drug abuse, or dependence) has been consistently reported in the literature. However, this literature has been based almost exclusively on male only samples and, therefore, the findings may not generalize to females. Methods: First-degree relatives from a large sample of pediatrically and psychiatrically referred girls with (123 probands, 403 relatives) and without ADHD (112 probands, 359 relatives) were comprehensively assessed by blind raters with structured diagnostic interviews. Familial risk analysis examined the risks in first-degree relatives for ADHD and PSUD (alcohol or drug abuse or dependence) after stratifying probands by the presence and absence of these disorders. Results: ADHD in the proband significantly increased the risk for ADHD in relatives independently of the comorbidity with PSUD. PSUD in the proband was associated with a significantly increased risk for PSUD in relatives regardless of ADHD status. There was no evidence of co-segregation or non-random mating in the families of probands with ADHD and PSUD. Conclusions: Patterns of familial risk analysis suggest that the association between ADHD and PSUD in adolescent females is most consistent with the hypothesis that these disorders are independently transmitted, although the hypothesis of variable expressivity could not be ruled out. These findings are consistent with previously reported patterns of familial associations between ADHD and PSUD found in adolescent males. Longer follow-up periods are needed to more fully clarify the relationship between ADHD and PSUD, as well as provide adequate power for separate analyses of alcohol and drug use. [ABSTRACT FROM AUTHOR]

Objective: To assess the effectiveness and tolerability of ziprasidone for treating pediatric mania. Methods: This was an eight-week, open-label, prospective study of ziprasidone monotherapy (57.3 ± 33.9 mg/day) in 21 bipolar youth [manic, mixed, or bipolar not otherwise specified (NOS); 6–17 years old]. Assessments included the Young Mania Rating Scale (YMRS), Clinical Global Impressions-Improvement scale (CGI-I), and Brief Psychiatric Rating Scale (BPRS). Adverse events were assessed through spontaneous self-reports, vital signs, weight monitoring, and laboratory analysis. Results: Fourteen of the 21 youth (67%) completed the study. Ziprasidone treatment was associated with clinically and statistically significant improvement in mean YMRS scores (−10.8 ± 8.4, p < 0.0001) and 57% had a CGI-I ≤2 at endpoint. Ziprasidone was well tolerated with no statistically significant increase in body weight (0.6 ± 0.4 kg, p = 0.2) or QTc interval (−3.7 ± 4.7, p = 0.5). Conclusions: Open-label ziprasidone treatment was associated with a significant short-term improvement of symptoms of pediatric bipolar disorder. Future placebo-controlled, double-blind studies are warranted. [ABSTRACT FROM AUTHOR]

This study evaluates the performance of boys with Attention Deficit Hyperactivity Disorder (ADHD) on the Rey-Osterrieth Complex Figure (ROCF) taking into consideration familiality and comorbid psychiatric and learning disorders (LD). Sixty-five children with ADHD performed at developmentally lower levels of Copy Organization and Recall Style than did 45 controls. ADHD children with LD scored significantly lower on Copy Organization than did ADHD children without LD, whereas psychiatric comorbidity and familiality had no effect. These results suggest that a developmental analysis of the ROCF identifies organizational difficulties associated with ADHD and that these impairments cannot simply be attributed to comorbidities associated with ADHD. [ABSTRACT FROM AUTHOR]

Enuresis and attention deficit hyperactivity disorder (ADHD) are common childhood disorders that often co-occur. Although each has been linked to neurodevelopmental immaturity and increased risk for psychopathology, the clinical correlates of enuresis remain unclear. Subjects were 140 6-17-year-old boys with DSM-III-R ADHD and 120 non-ADHD controls. Information on enuresis and psychiatric diagnoses was obtained in a standardized manner blind to the child's clinical status. Our results show that (1) enuresis did not increase the risk for psychopathology in children with or without ADHD; (2) enuresis was not associated with psychosocial adversity or developmental immaturity; (3) enuresis was associated with increased risk for learning disability, impaired intellectual functioning, and impaired school achievement in normal control children but not in children with ADHD; and (4) the same pattern of findings was obtained after stratifying children with enuresis by primary versus secondary and by nocturnal versus diurnal subtypes. These results suggest that the clinical implications of enuresis may differ for ADHD and non-ADHD children. [ABSTRACT FROM AUTHOR]

Attention-deficit hyperactivity disorder (ADHD) is a common behavioral disorder affecting about 4-8% of children. ADHD persists into adulthood in around 65% of cases, either as the full condition or in partial remission with persistence of symptoms. Pharmacological, animal and molecular genetic studies support a role for genes of the dopaminergic system in ADHD due to its essential role in motor control, cognition, emotion, and reward. Based on these data, we analyzed two functional polymorphisms within the DRD4 gene (120 bp duplication in the promoter and 48 bp VNTR in exon 3) in a clinical sample of 1,608 adult ADHD patients and 2,352 controls of Caucasian origin from four European countries that had been recruited in the context of the International Multicentre persistent ADHD CollaboraTion (IMpACT). Single-marker analysis of the two polymorphisms did not reveal association with ADHD. In contrast, multiple-marker meta-analysis showed a nominal association (P = 0.02) of the L-4R haplotype (dup120bp-48bpVNTR) with adulthood ADHD, especially with the combined clinical subtype. Since we previously described association between adulthood ADHD and the dopamine transporter SLC6A3 9R-6R haplotype (3'UTR VNTR-intron 8 VNTR) in the same dataset, we further tested for gene × gene interaction between DRD4 and SLC6A3. However, we detected no epistatic effects but our results rather suggest additive effects of the DRD4 risk haplotype and the SLC6A3 gene., (Copyright © 2011 Wiley-Liss, Inc.)

Although attention-deficit/hyperactivity disorder (ADHD) is associated both with brain alterations in attention and executive function (EF) circuitry and with genetic variations within the dopamine system (including the dopamine transporter gene [SLC6A3]), few studies have directly investigated how genetic variations are linked to brain alterations. We sought to examine how a polymorphism in the 3' untranslated region (UTR) of SLC6A3, associated with ADHD in meta-analysis, might contribute to variation in dorsal anterior cingulate cortex (dACC) function in subjects with ADHD. We collected fMRI scans of 42 individuals with ADHD, all of European descent and over the age of 17, while they performed the multi-source interference task (MSIT), a cognitive task shown to activate dACC. SLC6A3 3' UTR variable number tandem repeat (VNTR) polymorphisms were genotyped and brain activity was compared for groups based on allele status. ADHD individuals homozygous for the 10R allele showed significant hypoactivation in the left dACC compared to 9R-carriers. Exploratory analysis also showed trends toward hypoactivation in the 10R homozygotes in left cerebellar vermis and right lateral prefrontal cortex. Further breakdown of genotype groups showed similar activation in individuals heterozygous and homozygous for the 9R allele. Alterations in activation of attention and EF networks found previously to be involved in ADHD are likely influenced by SLC6A3 genotype. This genotype may contribute to heterogeneity of brain alterations found within ADHD samples., ((c) 2009 Wiley-Liss, Inc.)

Results of behavioral genetic and molecular genetic studies have converged to suggest that both genes contribute to the development of ADHD. Although prior linkage studies have produced intriguing results, their results have been inconsistent, with no clear pattern of results emerging across studies. We genotyped 5,980 SNPs across the genome in 1,187 individuals from families with children diagnosed with ADHD. We then performed two nonparametric linkage analyses on ADHD families: (1) an affected sibling pair linkage analysis on 217 families with 601 siblings diagnosed with ADHD and (2) a variance components linkage analysis using the number of ADHD symptoms as the phenotype on 260 families with 1,100 phenotyped siblings. The affection status linkage analysis had a maximum LOD score of 1.85 on chromosome 8 at 54.2 cM. The maximum LOD score in the variance components linkage analysis was 0.8 on chromosome 8 at 93.4 cM. The absence of regions of significant or suggestive linkage in these data suggest that there are no genes of large effect contributing to the ADHD phenotype., (Copyright 2007 Wiley-Liss, Inc.)

Several studies have evaluated the association between individual polymorphisms and response to methylphenidate (MPH) in subjects with attention-deficit/hyperactivity disorder (ADHD). There are few replication studies for each polymorphism of interest and results are sometimes inconsistent in this field. Although data collection from multiple international sites would allow large sample sizes, this approach has been criticized for introducing sampling variability due to differences in ethnicity and methodology between studies. To examine these issues, we aggregated nine pharmacogenetic studies from four different continents and conducted a two stage analysis: (a) we evaluated the role of methodological aspects in the variability of ADHD symptom improvement between studies using meta-regression analysis; (b) we assessed the role of individual characteristics of the subjects in the variability of ADHD symptoms improvement using multivariate regression analysis in the same data sets. At the study level, from five evaluated factors, only the design of the study (open studies vs. randomized controlled trials) was significantly associated with heterogeneity of results (P = 0.001). At the individual level, age (P < 0.001), comorbid oppositional defiant disorder (P < 0.001), and pre-treatment scores (P < 0.001) were associated with change of ADHD scores with treatment in the final multivariate model. Our results suggest that joint analyses of pharmacogenetic studies are feasible and promising, since fixed variables, such as the site where the study was conducted, were not related to results. Nevertheless, stratified analyses according to the design of the study must be preferentially conducted and the role of individual factors such as demographic data and comorbid profile as confounders should be assessed., (Copyright 2008 Wiley-Liss, Inc.)

A growing body of literature finds gender differences in ADHD. However, little is known about the causes of these differences. One possibility is that ADHD risk genes have sexually dimorphic effects. We have investigated four ADHD candidate genes (COMT, SLC6A2, MAOA, SLC6A4) for which there is evidence of sexually dimorphic effects. Past neurobiological and genetic studies suggest that COMT, and SLC6A4 variants may have a greater influence on males and that SLC6A2, and MAOA variants may have a greater influence on females. Our results indicate that genetic associations are stronger when stratified by sex and in the same direction as the previous neurobiological studies indicate: associations were stronger in males for COMT, SLC6A4 and stronger in females for SLC6A2, MAOA. Moreover, we found a statistically significant gender effect in the case of COMT (P = 0.007) when we pooled our work with a prior study. In conclusion, we have found some evidence suggesting that the genetic association for these genes with ADHD may be influenced by the sex of the affected individual. Although our results are not fully validated yet, they should motivate further investigation of gender effects in ADHD genetic association studies., (Copyright 2008 Wiley-Liss, Inc.)

Genetic contribution to the development of attention deficit hyperactivity disorder (ADHD) is well established. Seven independent genome-wide linkage scans have been performed to map loci that increase the risk for ADHD. Although significant linkage signals were identified in some of the studies, there has been limited replications between the various independent datasets. The current study gathered the results from all seven of the ADHD linkage scans and performed a Genome Scan Meta Analysis (GSMA) to identify the genomic region with most consistent linkage evidence across the studies. Genome-wide significant linkage (P(SR) = 0.00034, P(OR) = 0.04) was identified on chromosome 16 between 64 and 83 Mb. In addition there are nine other genomic regions from the GSMA showing nominal or suggestive evidence of linkage. All these linkage results may be informative and focus the search for novel ADHD susceptibility genes., (Copyright 2008 Wiley-Liss, Inc.)

An emerging literature has demonstrated an association between the dopamine D4 receptor (DRD4) gene and volumetric brain abnormalities in children with ADHD. However, these results have not been extended to adults and have not addressed the impact of comorbidity. Our objective was to examine the DRD4 7R gene and volumetric brain abnormalities in adults with ADHD while accounting for comorbidity with bipolar disorder (BPD). Subjects were male and female adult outpatient referrals stratified into two diagnostic groups: 24 with ADHD, 19 with ADHD and BPD, as well as 20 male and female adult community controls without ADHD or BPD. We measured volumes (cm(3)) of a priori selected brain regions (superior frontal, middle frontal, anterior cingulate, and cerebellum cortices) by structural magnetic resonance imaging. Among adults with ADHD, subjects with the 7-repeat allele of the DRD4 gene had a significantly smaller mean volume in the superior frontal cortex and cerebellum cortex compared to subjects without this allele. In contrast, no such effects were detected in the adults with ADHD + BPD or controls. Our findings suggest that volumetric abnormalities in the dorsolateral prefrontal cortex and cerebellum may represent an intermediate neuroanatomical phenotype between DRD4 genotype and the clinical expression of ADHD in adults, but only in ADHD subjects without comorbid BPD. These result support the heterogeneity of ADHD and provides insights as to its underlying pathophysiology., (Copyright 2008 Wiley-Liss, Inc.)

We conducted a genome-wide association study of symptom response in an open-label study of a methylphenidate transdermal system (MTS). All DNA extraction and genotyping was conducted at SUNY Upstate Medical University using the Affymetrix Genome-Wide Human SNP Array 6.0. All quality control and association analyses were conducted using the software package PLINK. After data cleaning and quality control, there were 187 subjects (72% (N = 135) male) with mean age 9.2 +/- 2.0 years and 319,722 SNPs available for analysis. The most statistically significant association (rs9627183 and rs11134178; P = 3 x 10(-6)) fell short of the threshold for a genome-wide significant association. The most intriguing association among suggestive findings (rs3792452; P = 2.6 x 10(-5)) was with the metabotropic glutamate receptor 7 gene (GRM7) as it is expressed in brain structures also previously associated with ADHD. Among the 102 available SNPs covering previously studied candidate genes, two SNPs within the norepinephrine transporter gene (NET, SLC6A2) were significant at P < or = 1 x 10(-2). These results should be considered preliminary until replicated in larger adequately powered, controlled samples but do suggest that noradrenergic and possibly glutaminergic genes may be involved with response to methylphenidate., (Copyright 2008 Wiley-Liss, Inc.)

The dopamine transporter gene (SLC6A3) is a compelling candidate for pediatric bipolar disorder because (a) it has been associated with ADHD, (b) bipolar comorbidity with ADHD has been hypothesized to be an etiologically distinct familial subtype (c) blockade of the dopamine transporter with psychostimulants can induce mania in susceptible individuals and (d) previous studies have implicated the gene in bipolar disorder in adults. We conducted a family-based association study of SLC6A3 in 170 affected offspring trios defined by a child (12.9 +/- 5.3 years of age)with DSM-IV Bipolar-I disorder. Twenty-eight tag SNPs were chosen from the CEU (European) population of the International HapMap project (www.hapmap.org). Results indicated nominally positive association for 4 SNPs (rs40184, rs11133767, rs3776512, and rs464049), but only rs40184 survived correction for multiple statistical comparisons (P = 0.038). This is the first examination of the association with SLC6A3 and bipolar disorder in children and, like previous findings in adults with bipolar disorder, we found evidence of association with SNPs in the 3' region of the gene. These data provide suggestive evidence supporting a role for SLC6A3 in the etiology of pediatric bipolar disorder.

A polymorphism in the dopamine transporter gene (DAT1) has been previously associated with ADHD and methylphenidate has been hypothesized to block the dopamine transporter. The goal of this study was to examine whether a 40-bp variable number of tandem repeats (VNTR) of DAT1 moderate response and adverse effects associated with methylphenidate treatment of adults with ADHD. Subjects were 106 adults with ADHD enrolled in 6-week randomized placebo-controlled parallel design trials of methylphenidate (OROS and immediate release preparations). There was no evidence of an association between DAT1 VNTR and response to methylphenidate (F(2,100) = 0.04, P = 0.9). Similarly, there was no pattern of statistically significant association with DAT1 VNTR and cardiovascular or spontaneously reported adverse effects. We failed to identify an association with DAT1 and the response or tolerability of methylphenidate in adults with ADHD., ((c) 2006 Wiley-Liss, Inc.)