Development, preliminary validation and reliability of the colourful 'My Feelings Form' self-report for young children.

BACKGROUND: Patient-reported outcome measures place the patient at the centre of his/her care. There are calls to introduce child-reported outcome measures to mental health services. We aimed to (a) develop an age-appropriate patient-reported outcome measure for children's mental health, and (b) validate this in a primary school and Child and Adolescent Mental Health Service (CAMHS). METHODS: A list of items to measure children's mental health was proposed (Draft 1) and revised to 14 items following focus group and user consultation (Draft 2). A colourful, cartoon and emoji version was created in consultation with children (Draft 3); a professional cartoon artist created the final 'My Feelings Form' (MFF), with usability feedback (Draft 4). The MFF was tested by 317 children aged 4-13 years from one mixed-gender primary school at two time points in 1 day, and 25 children aged 4-13 years from CAMHS. Results were analysed using test-retest reliability and exploratory factor analysis; a receiver operator characteristic curve was constructed. RESULTS: The CAMHS group scored significantly higher than the school group for the mean total score (23.5 ± 11.3 vs. 16.1 ± 6.2) and for 10 items. Test-retest reliability was acceptable (correlation = 0.74, p < .001). Exploratory factor analysis using 10 informative items identified two factors - emotional factor (Cronbach's alpha = 0.74) and function factor (Cronbach's alpha = 0.59). The revised 10-item form has a Cronbach's alpha of 0.77; a cut-off of 12 has a sensitivity of 80% and specificity of 60%, indicating that it correctly identified 80% of those who were attending CAMHS and gave 60% of the schoolchildren a negative result. CONCLUSIONS: The colourful MFF was co-produced with children, and preliminary data suggest that it is a useful patient-reported outcome measure for children's mental health.

Which Measures From a Sustained Attention Task Best Predict ADHD Group Membership?

Difficulty with sustaining attention to a task is a hallmark of ADHD. It would be useful to know which measures of sustained attention best predict a diagnosis of ADHD. Participants were 129 children with a diagnosis of ADHD and 129 matched controls who completed the fixed Sustained Attention to Response Task (SART). The number of commission and omission errors, standard deviation of response time (SDRT), tau, fast and slow frequency variability, d-prime, and mu were able to successfully classify children with and without ADHD. The mean response time, criterion, and sigma were not able to classify participants. The best classifiers were d-prime (0.75 Area Under the Receiver Operated Characteristic), tau (.74), SDRT (0.74), omission errors (0.72), commission errors (0.71), and SFAUS (0.70). This list of the best classifier measures derived from the SART may prove useful for the planning of future studies.

COVID-19 and mental health of primary school children: Comparison of 2019 and 2020.

INTRODUCTION: It is believed that the COVID-19 pandemic and associated global school closures may have an adverse effect on children's mental health. METHODS: We performed repeated measures of the mental health of children attending one primary school in Ireland before and during the quarantine phase of the first wave of the pandemic. We used the 'My Feelings Form', which is a 14-item colourful self-report measure which was completed in the classroom in 2019 and via postal survey in 2020. RESULTS: We had an 87% response rate in 2019 and a 35% response rate via postal return in 2020. We found no evidence of a change in mean measures of mental health between 2019 and 2020, in the 35% who responded in 2020. CONCLUSION: There is a cohort of children who were not adversely affected by the first wave of COVID-19 pandemic and associated school closures in Ireland.

Review: systematic review of effectiveness of art psychotherapy in children with mental health disorders.

Art therapy and art psychotherapy are often offered in Child and Adolescent Mental Health services (CAMHS). We aimed to review the evidence regarding art therapy and art psychotherapy in children attending mental health services. We searched PubMed, Web of Science, and EBSCO (CINHAL®Complete) following PRISMA guidelines, using the search terms ("creative therapy" OR "art therapy") AND (child* OR adolescent OR teen*). We excluded review articles, articles which included adults, articles which were not written in English and articles without outcome measures. We identified 17 articles which are included in our review synthesis. We described these in two groups-ten articles regarding the treatment of children with a psychiatric diagnosis and seven regarding the treatment of children with psychiatric symptoms, but no formal diagnosis. The studies varied in terms of the type of art therapy/psychotherapy delivered, underlying conditions and outcome measures. Many were case studies/case series or small quasi-experimental studies; there were few randomised controlled trials and no replication studies. However, there was some evidence that art therapy or art psychotherapy may benefit children who have experienced trauma or who have post-traumatic stress disorder (PTSD) symptoms. There is extensive literature regarding art therapy/psychotherapy in children but limited empirical papers regarding its use in children attending mental health services. There is some evidence that art therapy or art psychotherapy may benefit children who have experienced trauma. Further research is required, and it may be beneficial if studies could be replicated in different locations.

AdCom study-adolescent communication group therapy for externalising disorders.

BACKGROUND: Communication difficulties are associated with oppositional symptoms in young people. We hypothesise that a communication group intervention will reduce oppositional symptoms in young people. Previous research on communication and social skills training in young people with externalising disorders is limited. AIMS: We aimed to (1) develop and describe a group communication intervention to promote social competence in adolescents with behaviour difficulties, for use in CAMHS with those with attention-deficit/hyperactivity disorder (ADHD)/externalising disorders, and (2) collect pilot data on the effectiveness of this intervention. METHODS: We developed and delivered a programme of eight sessions to eight adolescents aged 12 to 13 years. We describe the intervention and challenges running the programme. We present pilot study data on pre- and post-oppositional symptoms. RESULTS: Our programme was relatively well attended; pilot data indicated a small reduction in oppositional symptoms in all participants. Challenges in running the group were noted. CONCLUSIONS: Our pilot study data suggest that further research is needed to study the effects of a communication group intervention on oppositional symptoms in a larger number of adolescents.

Social communication deficits and restricted repetitive behavior symptoms in Tourette syndrome.

Background: Autism spectrum disorders (ASD) have been found to occur more frequently in individuals with Tourette syndrome (TS) than in the general population. Similarities exist between ASD and TS clinically, which suggests a potential relationship between the two conditions. Purpose: The purpose of this study was to explore the occurrence of autism-related features in ASD and TS, focusing on areas of overlap and difference. Patients and methods: This study examined the nature and extent of autistic traits as measured by the Social Communication Questionnaire (SCQ) in a sample with a diagnosis of TS, a sample diagnosed to have ASD, and a normative general population sample. Results: The TS sample had significantly higher mean SCQ scores than the general population, but generally lower scores than the ASD sample. The group differences in mean SCQ scores between the TS and ASD sample were significant except in the domain of restricted repetitive behaviours (RRB). Conclusion: This suggests that ASD traits occur commonly in the TS population, with a significant overlap in certain clinical features. This was especially the case for complex movements or repetitive behaviours, which may represent either: i) a shared phenotype which is subclinical, ii) a phenocopy where some clinical symptoms mimic each other, or iii) a co-morbidity. Awareness of this association can be useful in identifying these symptoms as part of the comprehensive assessment of TS and addressing these to improve the overall clinical outcomes in these patients.

Child Art Psychotherapy in CAMHS in Ireland-a parent satisfaction study.

OBJECTIVES: We aimed to evaluate parent satisfaction with the Vasarhelyi method of Child Art Psychotherapy offered at two Child and Adolescent Mental Health teams by postal survey using the Client Satisfaction Questionnaire, and by performing a qualitative interview. METHODS: Parents of 29 children who attended Child Art Psychotherapy over the previous 4 years were invited to participate-they were sent the Client Satisfaction Questionnaire and invited to attend for an interview about Child Art Psychotherapy. The postal survey was followed up by a telephone call to complete missing surveys. The Client Satisfaction Questionnaire has a 4-point Likert scale with a minimum score of 8 and maximum score (highest satisfaction) of 32. RESULTS: Fourteen Client Satisfaction questionnaires were returned indicating a response rate of 48%. The mean age of the children who attended CAP was 10.84 years. The mean CSQ-8 score was 25.6 (95% CI 22.0-29.3) with a range of 8 to 32. Eighty-five percent of parents indicated that they were satisfied on all questions regarding the service of CAP their child received. One of 29 parents attended for interview and 4 themes were identified in the interview: (1) the importance of the child's opinion, (2) behavioural change occurred during and after CAP, (3) the parent would recommend CAP to others, and (4) parental expectations of therapy and level of engagement. CONCLUSION: Parents are satisfied with the Vasarhelyi method of Child Art Psychotherapy.

The Home Observation Measure of the Environment is associated with symptoms of ADHD and oppositionality in a CAMHS sample.

BACKGROUND: Severe early deprivation has a causal role in attention-deficit/hyperactivity disorder (ADHD). Adversity in the home is associated with increased ADHD and oppositional symptoms in children with ADHD. We aimed to replicate this in an independent clinic sample. METHODS: A total of 247 sequential families with a child referred to child and adolescent mental health services (CAMHS) were invited to participate; 100 families completed the study. The Home Observation Measure of the Environment (HOME) assessment was completed in the family home; parents completed the Conners' Rating Scale. RESULTS: A less supportive home was associated with more symptoms of inattention ( r = .33, p = .001), hyperactivity/impulsivity ( r = -.22, p = .028) and oppositionality ( r = -.48, significant at p < .000001). CONCLUSION: The HOME correlates with ADHD and oppositional symptom severity in a clinic sample; more research is required to ascertain whether this is a causal association and the direction of causation. If causal, then the modification of the home environment may be a treatment strategy for ADHD.

Childhood-Diagnosed ADHD, Symptom Progression, and Reversal Learning in Adulthood.

OBJECTIVE: ADHD persists in up to 60% into adulthood, and the reasons for persistence are not fully understood. The objective of this study was to characterize the neurofunctional basis of decision making in those with a childhood diagnosis of ADHD with either persistent or remitted symptoms in adulthood versus healthy control participants. METHOD: Thirty-two adults diagnosed with ADHD as children were split into persistent ( n = 18) or remitted ( n = 14) ADHD groups. Their neural activity and neurofunctional connectivity during a probabilistic reversal learning task were compared with 32 healthy controls. RESULTS: Remitters showed significantly higher neural connectivity in final reversal error and probabilistic error conditions, and persisters depict higher neural connectivity in reversal errors than controls at a family-wise error (FWE) corrected whole-brain corrected threshold. CONCLUSION: Remitters may have utilized higher neural connectivity than controls to make successful decisions. Also, remitters may have utilized compensatory strategies to override any potential underlying ADHD deficits.

Child art psychotherapy in CAMHS: Which cases are referred and which cases drop out?

BACKGROUND: The Vasarhelyi method of child art psychotherapy (CAP) is offered at certain Child and Adolescent Mental Health Services. Children attend three introductory sessions, and then choose to continue weekly CAP or conclude the sessions. AIMS: This study aims to identify the clinical disorders and characteristics of patients referred to CAP, and to determine who engages with the therapy. METHODS: A retrospective review of the clinical records of 67 children who attended CAP in DNCC/Mater CAMHS over 13 years was performed. The data was analysed using Microsoft Excel 12.0 and SPSS version 20. RESULTS: 67 children (57 % male and 43 % female) aged 5-17 years participated in CAP with an average age of 10.6 years. Children attended an average of 14 sessions of CAP, with a range of 1-61 sessions (mean of 13.8 ± 12.9 sessions). Anxiety disorder (28 %), behaviour disorder/ODD (25 %), and ADHD (21 %) are the most common diagnoses referred. These diagnoses along with autism spectrum disorder (ASD) had the highest overall engagement, while those with depression engaged the least. Children with ADHD and with ASD attended high numbers of sessions (with a mean of 23 and 19 respectively). Those who experienced acute life events or difficulties in the home engaged well (60 and 40 % respectively). There was no significant difference found in the percentage of appointments attended by males in comparison to females. CONCLUSION: CAP is generally acceptable to children, with a high average attendance rate. It was noted that children with ADHD and with ASD engaged well with the therapy for prolonged periods, whereas children with depression did not engage so well. We suggest that CAMHS clinics should consider referring children diagnosed with ADHD and children diagnosed with ASD to CAP as an adjunct to other therapies. We suggest that individuals with depression should be referred initially to other therapeutic services as the engagement with CAP was relatively poor.

Impaired reward processing in the human prefrontal cortex distinguishes between persistent and remittent attention deficit hyperactivity disorder.

Symptoms of attention deficit hyperactivity disorder (ADHD) in children often persist into adulthood and can lead to severe antisocial behavior. However, to-date it remains unclear whether neuro-functional abnormalities cause ADHD, which in turn can then provide a marker of persistent ADHD. Using event-related functional magnetic resonance imaging (fMRI), we measured blood oxygenation level dependent (BOLD) signal changes in subjects during a reversal learning task in which choice of the correct stimulus led to a probabilistically determined 'monetary' reward or punishment. Participants were diagnosed with ADHD during their childhood (N=32) and were paired with age, gender, and education matched healthy controls (N=32). Reassessment of the ADHD group as adults resulted in a split between either persistent (persisters, N=17) or remitted ADHDs (remitters, N=15). All three groups showed significantly decreased activation in the medial prefrontal cortex (PFC) and the left striatum during punished correct responses, however only remitters and controls presented significant psycho-physiological interaction between these fronto-striatal reward and outcome valence networks. Comparing persisters to remitters and controls showed significantly inverted responses to punishment (P<0.05, family-wise error corrected) in left PFC region. Interestingly, the decreased activation shown after punishment was located in different areas of the PFC for remitters compared with controls, suggesting that remitters might have learned compensation strategies to overcome their ADHD symptoms. Thus, fMRI helps understanding the neuro-functional basis of ADHD related behavior differences and differentiates between persistent and remittent ADHD.

Attention network hypoconnectivity with default and affective network hyperconnectivity in adults diagnosed with attention-deficit/hyperactivity disorder in childhood.

IMPORTANCE: The neurobiological underpinnings of attention-deficit/hyperactivity disorder (ADHD) and particularly those associated with the persistence of ADHD into adulthood are not yet well understood. The correlation patterns in spontaneous neural fluctuations at rest are known as resting-state functional connectivity (RSFC) and could characterize ADHD-specific connectivity changes. OBJECTIVE: To determine the specific location of possible ADHD-related differences in RSFC between adults diagnosed as having ADHD in childhood and control subjects. DESIGN Using resting-state functional magnetic resonance imaging, we calculated and compared functional connectivity from attention, affective, default, and cognitive control networks involved in the psychopathology of ADHD between the ADHD and control groups. SETTING University psychiatric service and magnetic resonance imaging research center. PARTICIPANTS: Sixteen drug-free adults (5 women and 11 men; mean age, 24.5 years) diagnosed with combined-type ADHD in childhood and 16 healthy controls matched for age (mean age, 24.4 years), sex, handedness, and educational level recruited from the community. INTERVENTION: Functional magnetic resonance imaging. MAIN OUTCOMES AND MEASURES: Connectivity data from ventral and dorsal attention, affective, default, and cognitive control networks and ADHD symptoms derived from ADHD-specific rating instruments. RESULTS: Adults with ADHD showed significantly decreased RSFC within the attention networks and increased RSFC within the affective and default mode and the right lateralized cognitive control networks compared with healthy controls (P < .01, familywise error for whole-brain cluster correction). Lower RSFC in the ventral and dorsal attention network was significantly correlated with higher levels of ADHD symptoms (P < .001). CONCLUSIONS AND RELEVANCE: These RSFC findings might underpin a biological basis for adult ADHD and are functionally related to persistent inattention, disturbance in cognitive control, and emotional dysregulation in adults with ADHD. These findings need to be understood in the context of all aspects of brain function in ADHD.

fMRI activation during response inhibition and error processing: the role of the DAT1 gene in typically developing adolescents and those diagnosed with ADHD.

The DAT1 gene codes for the dopamine transporter, which clears dopamine from the synaptic cleft, and a variant of this gene has previously been associated with compromised response inhibition in both healthy and clinical populations. This variant has also been associated with ADHD, a disorder that is characterised by disturbed dopamine function as well as problems with response inhibition. In the present study we used fMRI to investigate the role of dopaminergic genetic variation on executive functioning by comparing how activation associated with successful and unsuccessful inhibitions differs based on DAT1-genotype and ADHD-diagnosis in adolescents performing a go/nogo task. The results identify regional specificity concerning which functional differences can be attributed to the possession of the high risk DAT1 genotype, the clinical condition or an interaction between the two. During response inhibition, individuals with two copies of the 10-repeat allele showed increased activation in frontal, medial, and parietal regions, which may indicate that inhibition is more effortful for this group. Conversely, this group displayed a reduced error response in the parahippocampal gyrus, suggestive of reduced learning from errors. There were also a number of frontal, parietal, medial and occipital regions, where the relationship between genotype and fMRI-activation differed between the ADHD group and the typically developing adolescents. Finally, the ADHD group displayed decreased activation in parietal and (pre)frontal regions during response inhibition, and in frontal and medial brain regions on error trials.

Performance variability, impulsivity errors and the impact of incentives as gender-independent endophenotypes for ADHD.

BACKGROUND: Attention-deficit hyperactivity disorder (ADHD) is one of the most common and highly heritable child psychiatric disorders. There is strong evidence that children with ADHD show slower and more variable responses in tasks such as Go/Nogo tapping aspects of executive functions like sustained attention and response control which may be modulated by motivational factors and/or state-regulation processes. The aim of this study was (1) to determine if these executive functions may constitute an endophenotype for ADHD; (2) to investigate for the first time whether known modulators of these executive functions may also be familial; and (3) to explore whether gender has an impact on these measures. METHODS: Two hundred and five children with ADHD combined type, 173 nonaffected biological siblings and 53 controls with no known family history of ADHD were examined using a Go/Nogo task in the framework of a multi-centre study. Performance-measures and modulating effects of event-rate and incentives were examined. Shared familial effects on these measures were assessed, and the influence of gender was tested. RESULTS: Children with ADHD responded more slowly and variably than nonaffected siblings or controls. Nonaffected siblings showed intermediate scores for reaction-time variability, false alarms and omission errors under fast and slow event-rates. A slower event-rate did not lead to reduced performance specific to ADHD. In the incentive condition, mean reaction-times speeded up and became less variable only in children with ADHD and their nonaffected siblings, while accuracy was improved in all groups. Males responded faster, but also committed more false alarms. There were no interactions of group by gender. CONCLUSIONS: Reaction-time variability and accuracy parameters could be useful neuropsychological endophenotypes for ADHD. Performance-modulating effects of incentives suggested a familially driven motivational dysfunction which may play an important role on etiologic pathways and treatment approaches for ADHD. The effects of gender were independent of familial effects or ADHD-status, which in turn suggests that the proposed endophenotypes are independent of gender.

Dopaminergic haplotype as a predictor of spatial inattention in children with attention-deficit/hyperactivity disorder.

CONTEXT: A distinct pattern of selective attention deficits in attention-deficit/hyperactivity disorder (ADHD) has been difficult to identify. Heterogeneity may reflect differences in underlying genetics. OBJECTIVE: To document an objective deficit of selective attention in a large sample of children with and without ADHD using spatial orienting paradigms. By stratifying samples according to the gene dosage of a risk haplotype of the dopamine transporter gene (DAT1), we could determine whether genetic factors predict spatial inattention in ADHD. DESIGN: A case-control design was used. SETTING: Children with ADHD were recruited from clinics or support groups in Ireland. Typically developing children were recruited from schools in and around Dublin, Ireland. PARTICIPANTS: One hundred fifteen children were recruited (ADHD = 50, control = 65). Groups were matched for age but differed in estimated intelligence. INTERVENTION: Two versions of a visual spatial orienting task in which attention was directed by valid, neutral, or invalid cues to target locations. Sudden-onset peripheral cues (exogenous) and centrally presented predictive cues (endogenous) were used. MAIN OUTCOME MEASURES: To isolate an attention deficit in ADHD, groups were first compared using analysis of variance on the spatial orienting tasks. Multiple regression was used to assess the main effect of DAT1 haplotype status (heterozygous vs homozygous) and the interaction of diagnosis and genotype on those variables that discriminated children with and without ADHD. RESULTS: Children with ADHD displayed deficits in reorienting attention from invalidly cued spatial locations, particularly for targets in the left visual field. DAT1 haplotype status predicted spatial reorienting deficits for left visual field targets (P = .007) but there was also a significant interaction of diagnosis and genotype (P = .02), which revealed the greatest impairment in children with ADHD homozygous for the DAT1 haplotype. CONCLUSION: Heterogeneity in selective attention in ADHD can be explained by a replicated genetic risk factor for ADHD, the 10/3 DAT1 haplotype.

Delay and reward choice in ADHD: an experimental test of the role of delay aversion.

Children with attention deficit/hyperactivity disorder (ADHD) choose smaller sooner (SS) over larger later (LL) rewards more than controls. Here we assess the contributions of impulsive drive for immediate rewards (IDIR) and delay aversion (DAv) to this pattern. We also explore the characteristics of, and the degree of familiality in, ADHD SS responders. We had 360 ADHD probands; 349 siblings and 112 controls (aged between 6 to 17 years) chose between SS (1 point after 2 s) and LL reward (2 points after 30 s) outcomes on the Maudsley Index of Delay Aversion (Kuntsi, Oosterlaan, & Stevenson, 2001): Under one condition SS choice led to less overall trial delay under another it did not. ADHD participants chose SS more than controls under both conditions. This effect was larger when SS choice reduced trial delay. ADHD SS responders were younger, had lower IQ, more conduct disorder and had siblings who were more likely to be SS responders themselves. The results support a dual component model in which both IDIR and DAv contribute to SS choice in ADHD. SS choice may be a marker of an ADHD motivational subtype.

Autism symptoms in Attention-Deficit/Hyperactivity Disorder: a familial trait which correlates with conduct, oppositional defiant, language and motor disorders.

It is hypothesised that autism symptoms are present in Attention-Deficit/Hyperactivity Disorder (ADHD), are familial and index subtypes of ADHD. Autism symptoms were compared in 821 ADHD probands, 1050 siblings and 149 controls. Shared familiality of autism symptoms and ADHD was calculated using DeFries-Fulker analysis. Autism symptoms were higher in probands than siblings or controls, and higher in male siblings than male controls. Autism symptoms were familial, partly shared with familiality of ADHD in males. Latent class analysis using SCQ-score yielded five classes; Class 1(31%) had few autism symptoms and low comorbidity; Classes 2-4 were intermediate; Class 5(7%) had high autism symptoms and comorbidity. Thus autism symptoms in ADHD represent a familial trait associated with increased neurodevelopmental and oppositional/conduct disorders.

The dopamine receptor D4 7-repeat allele and prenatal smoking in ADHD-affected children and their unaffected siblings: no gene-environment interaction.

BACKGROUND: The dopamine receptor D4 (DRD4) 7-repeat allele and maternal smoking during pregnancy are both considered as risk factors in the aetiology of attention deficit hyperactivity disorder (ADHD), but few studies have been conducted on their interactive effects in causing ADHD. The purpose of this study is to examine the gene by environment (GxE) interaction of the DRD4 7-repeat allele and smoking during pregnancy on ADHD and oppositional behavior in families from the International Multicenter ADHD Genetics project; and further, to test the hypothesis that the direction of effect of the DRD4 7-repeat allele differs between ADHD affected and unaffected children. METHODS: Linear mixed models were used to assess main and interactive effects of the DRD4 7-repeat allele and smoking during pregnancy in 539 ADHD-affected children and their 407 unaffected siblings, aged 6-17 years. RESULTS: There was some evidence pointing to differential effects of the DRD4 7-repeat allele on ADHD and oppositional symptoms in the affected (fewer symptoms) and unaffected children (increasing ADHD symptoms of teacher ratings). Affected children were more often exposed to prenatal smoking than unaffected children. There were limited main effects of prenatal smoking on severity of symptoms. Given the number of tests performed, no indication was found for GxE interactions. CONCLUSION: Despite the large sample size, no GxE interactions were found. The impact of the DRD4 7-repeat allele might differ, depending on affected status and rater. This finding is discussed in terms of differences in the activity of the dopaminergic system and of different genes involved in rater-specific behaviors.

Conduct disorder and ADHD: evaluation of conduct problems as a categorical and quantitative trait in the international multicentre ADHD genetics study.

Attention-deficit/hyperactivity disorder (ADHD) is typically characterized by inattention, excessive motor activity, impulsivity, and distractibility. Individuals with ADHD have significant impairment in family and peer relations, academic functioning, and show high co-morbidity with a wide range of psychiatric disorders including oppositional defiant disorder (ODD), conduct disorder (CD), anxiety disorder, depression, substance abuse, and pervasive developmental disorder (PDD). Family studies suggest that ADHD + CD represents a specific subtype of the ADHD disorder with familial risk factors only partly overlapping with those of ADHD alone. We performed a hypothesis-free analysis of the GAIN-ADHD sample to identify markers and genes important in the development of conduct problems in a European cohort of individuals with ADHD. Using the Family-Based Association Test (FBAT) package we examined three measures of conduct problems in 1,043,963 autosomal markers. This study is part of a series of exploratory analyses to identify candidate genes that may be important in ADHD and ADHD-related traits, such as conduct problems. We did not find genome-wide statistical significance (P < 5 x 10(-7)) for any of the tested markers and the three conduct problem traits. Fifty-four markers reached strong GWA signals (P < 10(-5)). We discuss these findings in the context of putative candidate genes and the implications of these findings in the understanding of the etiology of ADHD + CD. We aimed to achieve insight into the genetic etiology of a trait using a hypothesis-free study design and were able to identify a number of biologically interesting markers and genes for follow-up studies.