Editorial: Can Improving Youth Mental Health Reduce Mortality?

It is well established that mental health conditions, including substance use disorders, are associated with premature mortality. A meta-analysis1 has demonstrated that this association holds across a range of diagnoses. Although the effect is stronger for schizophrenia, depression and anxiety contribute to more deaths overall because of their high prevalence rates. Moreover, more than two-thirds of associated deaths were explained by natural causes.1 The next logical questions, then, are as follows: which mechanisms underlie this association, and can they can be mitigated? In the current issue of JAACAP, Clark et al.2 aim to tie mental health symptoms and substance use to the acceleration of biological aging.

Polygenic Variation Underlying Educational Attainment and Attention-Deficit/Hyperactivity Disorder Indexes Behavior Ratings of Executive Functions in Child Psychiatry Outpatients

OBJECTIVE

We leveraged common genetic variation underlying ADHD, educational attainment (EA) and cognition (COG) to understand the nature of the Behavior Rating Inventory for Executive Functions (BRIEF) and its relationship to academic functioning.

METHOD

Participants were 991 youth, ages 7 to 17, consecutively referred for neuropsychiatric evaluation. Polygenic scores (PGS) for ADHD, EA, and COG were related to the BRIEF using regression analyses. Structural equation models were used to examine the associations between the PGS, BRIEF and academic outcomes (math, reading, and special education services [EDPLAN]).

RESULTS

After modeling the PGS together, only the EA and ADHD PGS significantly associated with the BRIEF. The BRIEF partially mediated the relationships between EA PGS with math and EDPLAN and fully mediated the relationship between ADHD PGS and EDPLAN.

CONCLUSION

Genetic data extend evidence that the BRIEF measures a construct relevant to educational success that differs from what is indexed by cognitive testing.

Editors' Best of 2023

There is, in the content of the Journal, an embarrassment of riches, and picking a "best" seems to demand a certain qualification: is the "best" the most interesting, most surprising, most educational, most important, most provocative, most enjoyable? How to choose? We are hardly unbiased and can admit to a special affection for the ones that we and the authors worked hardest on, modifying version after version into shape. Acknowledging these biases, here are the 2023 articles that we think deserve your attention or at least a second read.

Editors' Note: Third Annual Report Regarding JAACAP's Antiracist Journey

In 2020, we wrote to you of our dedication and vision for JAACAP "to be antiracist at every level."1 Over the last 3 years, we have pursued initiatives "to reshape the Journal to pursue this vision."2,3 In this article, we provide an update on these goals and initiatives (Figure 1). With the launching of our new open access journal, JAACAP Open,4 in late 2022, we now extend these initiatives to both scientific journals in the JAACAP family and aspire to be a leader among mental health journals in our intentional pursuit of antiracist policies and practices.

Differences in cognitive and academic performance during the COVID-19 pandemic in child psychiatric outpatients

This study examined the impact of the COVID-19 pandemic on cognitive and academic functioning in 574 youth presenting for outpatient clinical neuropsychiatric evaluations. We extended the prior literature by (a) determining the extent to which academic difficulties documented in population and community samples also occurred in child psychiatric outpatients; (b) evaluating the impact of the pandemic on neuropsychological functions relevant to academic performance (overall cognition, executive functions, and graphomotor skill); and (c) investigating the moderating impact of attention deficit hyperactivity disorder (ADHD) diagnosis. We compared cross-sectional scores on standardized measures for groups of youth evaluated at three time periods related to the COVID-19 pandemic: (a) prior to onset (PRIOR; N = 198), (b) during Year 1 (Y1; N = 149), and (c) during Year 2 (Y2; N = 227). Relative to overall cognitive ability, math scores were lower in Y1 and Y2 and reading scores were lower in Y2. Additionally, relative to overall cognitive ability, youth showed lower working memory in Y1 and lower processing speed in Y1 and Y2. Graphomotor skill and parent-rated executive functions (EF) did not vary significantly across the three time periods. ADHD status did not moderate psychometric test scores but did moderate parent-rated EF. These data suggest that the COVID-19 pandemic has negatively impacted academic and executive functions in child psychiatry outpatients. More research is needed to understand the long-term implications for development. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Youth Team Sports Participation Associates With Reduced Dimensional Psychopathology Through Interaction With Biological Risk Factors

Background

Physical activity is associated with mental health benefits in youth. Here, we used causal inference and triangulation with 2 levels of biology to substantiate relationships between sports participation and dimensional psychopathology in youths.

Methods

Baseline data from the Adolescent Brain Cognitive Development (ABCD) Study, which recruited children from 9 to 10 years of age across the United States, were included in multilevel regression models to assess relationships between lifetime participation in team sports (TS), individual sports, and nonsports activities and Child Behavior Checklist (CBCL) scores. We calculated polygenic risk scores for 8 psychiatric disorders to assess interactions with sports exposure on CBCL scores among European descendants. Following rigorous quality control, FreeSurfer-extracted brain magnetic resonance imaging structural data were examined for mediation of CBCL-activities relationships.

Results

Among those with complete data (N = 10,411), causal estimates using inverse probability weighting associated lifetime TS exposure with a 1.05-point reduction in CBCL total (95% CI, -1.54 to -0.56, p < .0001) a relationship that was specific to TS and strengthened with more years of exposure. Associations of attention-deficit/hyperactivity disorder polygenic loading with CBCL total weakened in European children with TS exposure (n = 4041; beta = -0.93, SE = 0.38, p = .013). Furthermore, TS participation and lower CBCL each associated with increased subcortical volumes (n = 8197). Subcortical volume mediated 5.5% of TS effects on CBCL total.

Conclusions

Our findings support prior associations of TS participation with lower psychopathology in youths through additional studies that demonstrate specificity, dose response, and coherence across 2 levels of biology. Longitudinal studies that further clarify causal relationships may justify interventional studies of TS for high-risk youth.

Behavior ratings of executive functions index multiple domains of psychopathology and school functioning in child psychiatric outpatients

Behavior rating scales of executive functions (EFs) are convenient and associate with academic and other outcomes; however, prior studies indicate limited correlations with psychometric tests of EFs. To better understand their potential for clinical utility, we examined the extent to which parent ratings on the Behavior Rating Inventory of Executive Function (BRIEF) related to psychopathology constructs and psychometric test scores in a sample of N = 692 psychiatric outpatients aged 8-17. Then, in a subsample of the youth (N = 261), we related the BRIEF, psychopathology constructs, and psychometric test scores to teacher ratings of school functioning. BRIEF scales were significantly associated with multiple types of psychopathology including ADHD, autism spectrum, mood, anxiety, conduct, oppositional defiant, and psychotic disorders. While the BRIEF showed limited associations with psychometric EF tests, its Global Executive Composite score explained additional variance in teacher-reported functioning beyond what was predicted by clinical diagnoses (additional explained variance of 9.9% in study skills) and psychometric tests (additional explained variance of 2.1% in learning problems and 4.5% in study skills). The Global Executive Composite was not significantly related to teacher-rated school functioning after psychiatric symptoms were accounted for. These findings support further investigation of the unique contribution of the BRIEF in clinical practice.

Genetic patterning for child psychopathology is distinct from that for adults and implicates fetal cerebellar development

Childhood psychiatric symptoms are often diffuse but can coalesce into discrete mental illnesses during late adolescence. We leveraged polygenic scores (PGSs) to parse genomic risk for childhood symptoms and to uncover related neurodevelopmental mechanisms with transcriptomic and neuroimaging data. In independent samples (Adolescent Brain Cognitive Development, Generation R) a narrow cross-disorder neurodevelopmental PGS, reflecting risk for attention deficit hyperactivity disorder, autism, depression and Tourette syndrome, predicted psychiatric symptoms through early adolescence with greater sensitivity than broad cross-disorder PGSs reflecting shared risk across eight psychiatric disorders, the disorder-specific PGS individually or two other narrow cross-disorder (Compulsive, Mood-Psychotic) scores. Neurodevelopmental PGS-associated genes were preferentially expressed in the cerebellum, where their expression peaked prenatally. Further, lower gray matter volumes in cerebellum and functionally coupled cortical regions associated with psychiatric symptoms in mid-childhood. These findings demonstrate that the genetic underpinnings of pediatric psychiatric symptoms differ from those of adult illness, and implicate fetal cerebellar developmental processes that endure through childhood.

Book Forum: An Introduction to the JAACAP Editorial Team

Children's books are often our first window into the magic of the written word. As child and adolescent psychiatrists, these books not only lay a foundation for our own introduction into reading, but also are a tool used to connect with the youth and families we serve. We felt there was no better way to continue to introduce some of the new members of JAACAP's Editorial Board than through reading reviews of their favorite children's books. Featured are book reviews from the JAACAP Editor-in-Chief, Associate Editor, and new Deputy Editors. Next month we will highlight children's book reviews from members of JAACAPOpen's inaugural Editorial Board.

Uncovering and mitigating bias in large, automated MRI analyses of brain development

Large, population-based MRI studies of adolescents promise transformational insights into neurodevelopment and mental illness risk 1,2. However, MRI studies of youth are especially susceptible to motion and other artifacts 3,4. These artifacts may go undetected by automated quality control (QC) methods that are preferred in high-throughput imaging studies, 5 and can potentially introduce non-random noise into clinical association analyses. Here we demonstrate bias in structural MRI analyses of children due to inclusion of lower quality images, as identified through rigorous visual quality control of 11,263 T1 MRI scans obtained at age 9-10 through the Adolescent Brain Cognitive Development (ABCD) Study6. Compared to the best-rated images (44.9% of the sample), lower-quality images generally associated with decreased cortical thickness and increased cortical surface area measures (Cohen's d 0.14-2.84). Variable image quality led to counterintuitive patterns in analyses that associated structural MRI and clinical measures, as inclusion of lower-quality scans altered apparent effect sizes in ways that increased risk for both false positives and negatives. Quality-related biases were partially mitigated by controlling for surface hole number, an automated index of topological complexity that differentiated lower-quality scans with good specificity at Baseline (0.81-0.93) and in 1,000 Year 2 scans (0.88-1.00). However, even among the highest-rated images, subtle topological errors occurred during image preprocessing, and their correction through manual edits significantly and reproducibly changed thickness measurements across much of the cortex (d 0.15-0.92). These findings demonstrate that inadequate QC of youth structural MRI scans can undermine advantages of large sample size to detect meaningful associations.

Polygenic association between attention-deficit/hyperactivity disorder liability and cognitive impairments

BACKGROUND

A recent genome-wide association study (GWAS) identified 12 independent loci significantly associated with attention-deficit/hyperactivity disorder (ADHD). Polygenic risk scores (PRS), derived from the GWAS, can be used to assess genetic overlap between ADHD and other traits. Using ADHD samples from several international sites, we derived PRS for ADHD from the recent GWAS to test whether genetic variants that contribute to ADHD also influence two cognitive functions that show strong association with ADHD: attention regulation and response inhibition, captured by reaction time variability (RTV) and commission errors (CE).

METHODS

The discovery GWAS included 19 099 ADHD cases and 34 194 control participants. The combined target sample included 845 people with ADHD (age: 8-40 years). RTV and CE were available from reaction time and response inhibition tasks. ADHD PRS were calculated from the GWAS using a leave-one-study-out approach. Regression analyses were run to investigate whether ADHD PRS were associated with CE and RTV. Results across sites were combined via random effect meta-analyses.

RESULTS

When combining the studies in meta-analyses, results were significant for RTV (R² = 0.011, β = 0.088, p = 0.02) but not for CE (R² = 0.011, β = 0.013, p = 0.732). No significant association was found between ADHD PRS and RTV or CE in any sample individually (p > 0.10).

CONCLUSIONS

We detected a significant association between PRS for ADHD and RTV (but not CE) in individuals with ADHD, suggesting that common genetic risk variants for ADHD influence attention regulation.

Associations Between Genetic Risk for Adult Suicide Attempt and Suicidal Behaviors in Young Children in the US

IMPORTANCE

Suicide rates have been increasing among youth in the US. While the heritability of suicide risk is well established, there is limited understanding of how genetic risk is associated with suicidal thoughts and behaviors in young children.

OBJECTIVE

To examine whether genetic susceptibility to suicide attempts (SAs) is associated with suicidal thoughts and behaviors in children.

DESIGN, SETTING, AND PARTICIPANTS

This case-control study examined data from the Adolescent Brain Cognitive Development (ABCD) study, a population-based longitudinal study of 11 878 US children enrolled at age 9 and 10 years from September 2016 to November 2018. Youth reports of suicidal ideation (SI) and SAs were obtained from the Kiddie Schedule for Affective Disorder and Schizophrenia at baseline and 2 subsequent years. After conservative quality control of genotype data, this analysis focused on 4344 unrelated individuals of European ancestry. Data analysis was conducted from November 2020 to February 2022.

MAIN OUTCOMES AND MEASURES

Children's lifetime experiences of SI and SAs were assessed each year from ages 9 to 10 years to ages 11 to 12 years. Polygenic risk scores (PRSs) for SAs were calculated for ABCD study participants based on the largest genome-wide association study of SA cases and controls of European ancestry (total sample n = 518 612).

RESULTS

Of 4344 children of European ancestry (2045 [47.08%] female; mean [SD] age, 9.93 [0.62] years), significant associations were found between children's SA PRSs and their lifetime SAs with the most robust association in the follow-up year 2 (odds ratio, 1.43 [95% CI, 1.18-1.75]; corrected P = 1.85 × 10-3; Nagelkerke pseudo R2 = 1.51%). These associations remained significant after accounting for children's sociodemographic backgrounds, psychopathology symptoms, parental histories of suicide and mental health, and PRSs for major depression and attention-deficit/hyperactivity disorder (likelihood ratio test P &lt; .05). Children's depressive mood and aggressive behavior were the most significant partial mediators of SA genetic risk on SAs (mediation analysis P &lt; 1 × 10-16). Children's behavioral problems, such as attention problems, rule-breaking behavior, and social problems, also partially mediated the association of SA PRSs with SAs (mediation analysis false discover rate &lt; 0.05).

CONCLUSIONS AND RELEVANCE

This study's findings indicate that there may be genetic factors associated with SA risk across the life span and suggest behaviors and conditions through which the risk could be mediated in childhood. Further research is warranted to examine whether incorporating genetic data could improve the identification of children at risk for suicide.

Genetic Association of Attention-Deficit/Hyperactivity Disorder and Major Depression With Suicidal Ideation and Attempts in Children: The Adolescent Brain Cognitive Development Study

BACKGROUND

Suicide is among the leading causes of death in children and adolescents. There are well-known risk factors of suicide, including childhood abuse, family conflicts, social adversity, and psychopathology. While suicide risk is also known to be heritable, few studies have investigated genetic risk in younger individuals.

METHODS

Using polygenic risk score analysis, we examined whether genetic susceptibility to major psychiatric disorders is associated with suicidal behaviors among 11,878 children enrolled in the ABCD (Adolescent Brain Cognitive Development) Study. Suicidal ideation and suicide attempt data were assessed using the youth report of the Kiddie Schedule for Affective Disorders and Schizophrenia for DSM-5. After performing robust quality control of genotype data, unrelated individuals of European descent were included in analyses (n = 4344).

RESULTS

Among 8 psychiatric disorders we examined, depression polygenic risk scores were associated with lifetime suicide attempts both in the baseline (odds ratio = 1.55, 95% CI = 1.10-2.18, p = 1.27 × 10-2) and in the follow-up year (odds ratio = 1.38, 95% CI = 1.08-1.77, p = 1.05 × 10-2), after adjusting for children's age, sex, socioeconomic backgrounds, family history of suicide, and psychopathology. In contrast, attention-deficit/hyperactivity disorder polygenic risk scores were associated with lifetime suicidal ideation (odds ratio = 1.15, 95% CI = 1.05-1.26, p = 3.71 × 10-3), suggesting a distinct contribution of the genetic risk underlying attention-deficit/hyperactivity disorder and depression on suicidal behaviors of children.

CONCLUSIONS

The largest genetic sample of suicide risk data in U.S. children suggests a significant genetic basis of suicide risk related to attention-deficit/hyperactivity disorder and depression. Further research is warranted to examine whether incorporation of genomic risk may facilitate more targeted screening and intervention efforts.

Identifying Pediatric Mood Disorders From Transdiagnostic Polygenic Risk Scores: A Study of Children and Adolescents

Objective: Mood disorders often co-occur with attention-deficit/hyperactive disorder (ADHD), disruptive behavior disorders (DBDs), and aggression. We aimed to determine if polygenic risk scores (PRSs) based on external genome-wide association studies (GWASs) of these disorders could improve genetic identification of mood disorders. Methods: We combined 6 independent family studies that had genetic data and diagnoses for mood disorders that were made using different editions of the Diagnostic and Statistical Manual of Mental Disorders (DSM). We identified mood disorders, either concurrently or in the future, in participants between 6 and 17 years of age using PRSs calculated using summary statistics of GWASs for ADHD, ADHD with DBD, major depressive disorder (MDD), bipolar disorder (BPD), and aggression to compute PRSs. Results: In our sample of 485 youths, 356 (73%) developed a subthreshold or full mood disorder and 129 (27%) did not. The cross-validated mean areas under the receiver operating characteristic curve (AUCs) for the 7 models identifying participants with any mood disorder ranged from 0.552 in the base model of age and sex to 0.648 in the base model + all 5 PRSs. When included in the base model individually, the ADHD PRS (OR = 1.65, P < .001), Aggression PRS (OR = 1.27, P = .02), and MDD PRS (OR = 1.23, P = .047) were significantly associated with the development of any mood disorder. Conclusions: Using PRSs for ADHD, MDD, BPD, DBDs, and aggression, we could modestly identify the presence of mood disorders. These findings extend evidence for transdiagnostic genetic components of psychiatric illness and demonstrate that PRSs calculated using traditional diagnostic boundaries can be useful within a transdiagnostic framework.

Distinct patterns of emotional and behavioral change in child psychiatry outpatients during the COVID-19 pandemic

BACKGROUND

Studies are documenting the impact of the COVID-19 pandemic on youth mental health. We extended this literature by characterizing a child psychiatric outpatient sample in the United States during the middle of the 2020-2021 school year. We also used a computational strategy to identify distinct patterns of psychopathology symptom change and examined correlates and predictors of such change. Among potential predictors were cognition and clinical diagnoses, which have not been studied in this context previously.

METHODS

Participants were 171 youth (aged 10.6 ± 3.1) referred for neuropsychiatric evaluation who enrolled in research and whose parents filled out a survey on COVID-19. The questionnaire included eight psychiatric and six psychosocial domains rated retrospectively prior to the pandemic and currently at the time of evaluation. We examined change in severity of individual domains with Wilcoxon signed-rank tests. We used a latent profile analysis (LPA) to identify groups with distinct symptom change profiles. Using multinomial logistic regression, we examined potential predictors and correlates of LPA-derived groups. Models controlled for age, sex, and assessment date and corrected for multiple testing.

RESULTS

Although the majority of individual psychopathology domains were worse on average during the 2020-2021 school year, youth showed distincive patterns of symptom change. In addition to a large group (72.2%) with relatively stable symptoms and a small group (6.4%) that improved on most symptoms, there were two groups with different constellations of worsening symptoms. These latter groups both showed increased sadness, anxiety and oppositionality; however, one had increased hyperactivity/impulsivity and no change in hopelessness while the other showed greater hopelessness and no change in hyperactivity. Symptoms related to the distinguishable domains of these groups predicted group membership, and changes in screen time, conflict with parents and social isolation were correlates of worsening. Cognition and lifetime clinical diagnoses failed to predict group membership.

CONCLUSIONS

In youth outpatients, psychiatric and psychosocial difficulties were worse on average during the school year following the spring 2020 COVID-19 lockdown; yet, some youth experienced greater and distinctive symptom change. A personalized approach to support may be needed as youth emerge from this period.

Neuropsychology consultation to identify learning disorders in children and adolescents: a proposal based on lessons learned during the COVID-19 pandemic

Learning disorders are common neurodevelopmental conditions, occurring both idiopathically and in the context of other medical conditions. They are frequently comorbid with other neurodevelopmental and psychiatric conditions. Delayed identification and treatment have been associated with significant negative psychosocial consequences. The need for pediatric neuropsychologists to efficiently screen for learning disorders is likely to increase in the months and years following the COVID-19 pandemic, which has severely disrupted access to educational services, especially for children who also face racial and economic disparities. In this paper, we describe a consultation model that can be used to screen for learning disorders and can be completed using both in-person and telemedicine visits. Implementation may result in earlier intervention for struggling children, increase access to neuropsychological services without increasing wait times for comprehensive evaluations, and provide opportunities for collaborations with other health professionals (e.g., pediatricians, therapists, psychiatrists, and neurologists).

Analysis of structural brain asymmetries in attention-deficit/hyperactivity disorder in 39 datasets

OBJECTIVE

Some studies have suggested alterations of structural brain asymmetry in attention-deficit/hyperactivity disorder (ADHD), but findings have been contradictory and based on small samples. Here, we performed the largest ever analysis of brain left-right asymmetry in ADHD, using 39 datasets of the ENIGMA consortium.

METHODS

We analyzed asymmetry of subcortical and cerebral cortical structures in up to 1,933 people with ADHD and 1,829 unaffected controls. Asymmetry Indexes (AIs) were calculated per participant for each bilaterally paired measure, and linear mixed effects modeling was applied separately in children, adolescents, adults, and the total sample, to test exhaustively for potential associations of ADHD with structural brain asymmetries.

RESULTS

There was no evidence for altered caudate nucleus asymmetry in ADHD, in contrast to prior literature. In children, there was less rightward asymmetry of the total hemispheric surface area compared to controls (t = 2.1, p = .04). Lower rightward asymmetry of medial orbitofrontal cortex surface area in ADHD (t = 2.7, p = .01) was similar to a recent finding for autism spectrum disorder. There were also some differences in cortical thickness asymmetry across age groups. In adults with ADHD, globus pallidus asymmetry was altered compared to those without ADHD. However, all effects were small (Cohen's d from -0.18 to 0.18) and would not survive study-wide correction for multiple testing.

CONCLUSION

Prior studies of altered structural brain asymmetry in ADHD were likely underpowered to detect the small effects reported here. Altered structural asymmetry is unlikely to provide a useful biomarker for ADHD, but may provide neurobiological insights into the trait.

Shared genetic background between children and adults with attention deficit/hyperactivity disorder

Attention deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental disorder characterized by age-inappropriate symptoms of inattention, impulsivity, and hyperactivity that persist into adulthood in the majority of the diagnosed children. Despite several risk factors during childhood predicting the persistence of ADHD symptoms into adulthood, the genetic architecture underlying the trajectory of ADHD over time is still unclear. We set out to study the contribution of common genetic variants to the risk for ADHD across the lifespan by conducting meta-analyses of genome-wide association studies on persistent ADHD in adults and ADHD in childhood separately and jointly, and by comparing the genetic background between them in a total sample of 17,149 cases and 32,411 controls. Our results show nine new independent loci and support a shared contribution of common genetic variants to ADHD in children and adults. No subgroup heterogeneity was observed among children, while this group consists of future remitting and persistent individuals. We report similar patterns of genetic correlation of ADHD with other ADHD-related datasets and different traits and disorders among adults, children, and when combining both groups. These findings confirm that persistent ADHD in adults is a neurodevelopmental disorder and extend the existing hypothesis of a shared genetic architecture underlying ADHD and different traits to a lifespan perspective.

Subcortical Brain Volume, Regional Cortical Thickness, and Cortical Surface Area Across Disorders: Findings From the ENIGMA ADHD, ASD, and OCD Working Groups

OBJECTIVE

Attention deficit hyperactivity disorder (ADHD), autism spectrum disorder (ASD), and obsessive-compulsive disorder (OCD) are common neurodevelopmental disorders that frequently co-occur. The authors sought to directly compare these disorders using structural brain imaging data from ENIGMA consortium data.

METHODS

Structural T1-weighted whole-brain MRI data from healthy control subjects (N=5,827) and from patients with ADHD (N=2,271), ASD (N=1,777), and OCD (N=2,323) from 151 cohorts worldwide were analyzed using standardized processing protocols. The authors examined subcortical volume, cortical thickness, and cortical surface area differences within a mega-analytical framework, pooling measures extracted from each cohort. Analyses were performed separately for children, adolescents, and adults, using linear mixed-effects models adjusting for age, sex, and site (and intracranial volume for subcortical and surface area measures).

RESULTS

No shared differences were found among all three disorders, and shared differences between any two disorders did not survive correction for multiple comparisons. Children with ADHD compared with those with OCD had smaller hippocampal volumes, possibly influenced by IQ. Children and adolescents with ADHD also had smaller intracranial volume than control subjects and those with OCD or ASD. Adults with ASD showed thicker frontal cortices compared with adult control subjects and other clinical groups. No OCD-specific differences were observed across different age groups and surface area differences among all disorders in childhood and adulthood.

CONCLUSIONS

The study findings suggest robust but subtle differences across different age groups among ADHD, ASD, and OCD. ADHD-specific intracranial volume and hippocampal differences in children and adolescents, and ASD-specific cortical thickness differences in the frontal cortex in adults, support previous work emphasizing structural brain differences in these disorders.

Translating Discoveries in Attention-Deficit/Hyperactivity Disorder Genomics to an Outpatient Child and Adolescent Psychiatric Cohort

OBJECTIVE

Genomic discoveries should be investigated in generalizable child psychiatric samples in order to justify and inform studies that will evaluate their use for specific clinical purposes. In youth consecutively referred for neuropsychiatric evaluation, we examined 1) the convergent and discriminant validity of attention-deficit/hyperactivity disorder (ADHD) polygenic risk scores (PRSs) in relation to DSM-based ADHD phenotypes; 2) the association of ADHD PRSs with phenotypes beyond ADHD that share its liability and have implications for outcome; and 3) the extent to which youth with high ADHD PRSs manifest a distinctive clinical profile.

METHOD

Participants were 433 youth, ages 7-18 years, from the Longitudinal Study of Genetic Influences on Cognition. We used logistic/linear regression and mixed effects models to examine associations with ADHD-related polygenic variation from the largest ADHD genome-wide association study to date. We replicated key findings in 5,140 adult patients from a local health system biobank.

RESULTS

Among referred youth, ADHD PRSs were associated with ADHD diagnoses, cross-diagnostic ADHD symptoms and academic impairment (odds ratios ∼1.4; R² values ∼2%-3%), as well as cross-diagnostic variation in aggression and working memory. In adults, ADHD PRSs were associated with ADHD and phenotypes beyond the condition that have public health implications. Finally, youth with a high ADHD polygenic burden showed a more severe clinical profile than youth with a low burden (β coefficients ∼.2).

CONCLUSION

Among child and adolescent outpatients, ADHD polygenic risk was associated with ADHD and related phenotypes as well as clinical severity. These results extend the scientific foundation for studies of ADHD polygenic risk in the clinical setting and highlight directions for further research.

The Shared Genetic Basis of Educational Attainment and Cerebral Cortical Morphology

Individual differences in educational attainment are linked to differences in intelligence, and predict important social, economic, and health outcomes. Previous studies have found common genetic factors that influence educational achievement, cognitive performance and total brain volume (i.e., brain size). Here, in a large sample of participants from the UK Biobank, we investigate the shared genetic basis between educational attainment and fine-grained cerebral cortical morphological features, and associate this genetic variation with a related aspect of cognitive ability. Importantly, we execute novel statistical methods that enable high-dimensional genetic correlation analysis, and compute high-resolution surface maps for the genetic correlations between educational attainment and vertex-wise morphological measurements. We conduct secondary analyses, using the UK Biobank verbal-numerical reasoning score, to confirm that variation in educational attainment that is genetically correlated with cortical morphology is related to differences in cognitive performance. Our analyses relate the genetic overlap between cognitive ability and cortical thickness measurements to bilateral primary motor cortex as well as predominantly left superior temporal cortex and proximal regions. These findings extend our understanding of the neurobiology that connects genetic variation to individual differences in educational attainment and cognitive performance.

Integrating questionnaire measures for transdiagnostic psychiatric phenotyping using word2vec

Background

Recent initiatives in psychiatry emphasize the utility of characterizing psychiatric symptoms in a multidimensional manner. However, strategies for applying standard self-report scales for multiaxial assessment have not been well-studied, particularly where the aim is to support both categorical and dimensional phenotypes.

Methods

We propose a method for applying natural language processing to derive dimensional measures of psychiatric symptoms from questionnaire data. We utilized nine self-report symptom measures drawn from a large cellular biobanking study that enrolled individuals with mood and psychotic disorders, as well as healthy controls. To summarize questionnaire results we used word embeddings, a technique to represent words as numeric vectors preserving semantic and syntactic meaning. A low-dimensional approximation to the embedding space was used to derive the proposed succinct summary of symptom profiles. To validate our embedding-based disease profiles, these were compared to presence or absence of axis I diagnoses derived from structured clinical interview, and to objective neurocognitive testing.

Results

Unsupervised and supervised classification to distinguish presence/absence of axis I disorders using survey-level embeddings remained discriminative, with area under the receiver operating characteristic curve up to 0.85, 95% confidence interval (CI) (0.74,0.91) using Gaussian mixture modeling, and cross-validated area under the receiver operating characteristic curve 0.91, 95% CI (0.88,0.94) using logistic regression. Derived symptom measures and estimated Research Domain Criteria scores also associated significantly with performance on neurocognitive tests.

Conclusions

Our results support the potential utility of deriving dimensional phenotypic measures in psychiatric illness through the use of word embeddings, while illustrating the challenges in identifying truly orthogonal dimensions.

Slow Processing Speed and Sluggish Cognitive Tempo in Pediatric Attention-Deficit/Hyperactivity Disorder: Evidence for Differentiation of Functional Correlates

The association between slow processing speed and sluggish cognitive tempo (SCT), a phenotype described within attention-deficit/hyperactivity disorder (ADHD) samples over the past decade, remains unclear. We examined whether SCT and processing speed predict different functional correlates within children and adolescents with ADHD. Participants were 193 clinically-referred youth meeting DSM ADHD criteria without comorbid conditions (mean age = 9.9 years, SD = 2.5; age range 6-16). The incremental utility of SCT and processing speed to predict (1) adaptive functioning and (2) academic achievement, after controlling for age, sex, medication status, and ADHD symptom burden, was assessed using hierarchical multiple regressions. SCT symptoms significantly predicted adaptive functioning, accounting for 6% of the variance, but did not predict academic achievement. Processing speed did not add incrementally to the prediction of adaptive functioning, but did predict academic achievement, accounting for 4% of the variance. Results suggest that SCT and processing speed differentially predict functional abilities not accounted for by ADHD symptom burden.

Brain Imaging of the Cortex in ADHD: A Coordinated Analysis of Large-Scale Clinical and Population-Based Samples

OBJECTIVE

Neuroimaging studies show structural alterations of various brain regions in children and adults with attention deficit hyperactivity disorder (ADHD), although nonreplications are frequent. The authors sought to identify cortical characteristics related to ADHD using large-scale studies.

METHODS

Cortical thickness and surface area (based on the Desikan-Killiany atlas) were compared between case subjects with ADHD (N=2,246) and control subjects (N=1,934) for children, adolescents, and adults separately in ENIGMA-ADHD, a consortium of 36 centers. To assess familial effects on cortical measures, case subjects, unaffected siblings, and control subjects in the NeuroIMAGE study (N=506) were compared. Associations of the attention scale from the Child Behavior Checklist with cortical measures were determined in a pediatric population sample (Generation-R, N=2,707).

RESULTS

In the ENIGMA-ADHD sample, lower surface area values were found in children with ADHD, mainly in frontal, cingulate, and temporal regions; the largest significant effect was for total surface area (Cohen's d=-0.21). Fusiform gyrus and temporal pole cortical thickness was also lower in children with ADHD. Neither surface area nor thickness differences were found in the adolescent or adult groups. Familial effects were seen for surface area in several regions. In an overlapping set of regions, surface area, but not thickness, was associated with attention problems in the Generation-R sample.

CONCLUSIONS

Subtle differences in cortical surface area are widespread in children but not adolescents and adults with ADHD, confirming involvement of the frontal cortex and highlighting regions deserving further attention. Notably, the alterations behave like endophenotypes in families and are linked to ADHD symptoms in the population, extending evidence that ADHD behaves as a continuous trait in the population. Future longitudinal studies should clarify individual lifespan trajectories that lead to nonsignificant findings in adolescent and adult groups despite the presence of an ADHD diagnosis.

Reliability and validity of the Thinking Skills Inventory, a screening tool for cross-diagnostic skill deficits underlying youth behavioral challenges

Deficits in a range of skill domains (including executive functioning, emotion regulation, social cognition and language/communication) are associated with disrupted youth behavior and functioning across mental health diagnoses. The identification of skill deficits are important for effective treatment planning, particularly for personalized interventions. While there are multiple ways to assess these skills, parent/caregiver reports represent an important information source. To date, no single, brief measure has been developed that gathers parent/caregiver ratings across this range of constructs. We have developed a short caregiver-report questionnaire (the Thinking Skills Inventory; TSI), to screen for skill deficits. Here, we examine the reliability and validity of this rating scale in 384 youth who were consecutively referred for neuropsychiatric evaluation. A primary caregiver completed the TSI as well as other established measures. Exploratory and confirmatory factor analyses support five subscales on the TSI: Attention and Working Memory, Language and Communication, Emotion Regulation, Cognitive Flexibility, and Social Thinking Skills. The subscales showed moderate to high internal consistency (Cronbach's alphas range from 0.84 to 0.91). Correlations with established caregiver-report measures confirm their convergent and discriminant validity, and associations with multiple clinical diagnoses and cross-diagnostic aggressive behavior further support the utility of the scale for our intended purpose. In sum, this free, brief measure is a valid and reliable way to identify variation in skill domains relevant to a range of psychopathology. The TSI may be useful in youth mental health settings to assist with treatment planning and to inform referral for further evaluation.

Association between child psychiatric emergency room outcomes and dimensions of psychopathology

OBJECTIVE

To determine the degree to which dimensional psychopathology predicts length of stay in an emergency department (ED) and need for hospital admission among children with psychiatric complaints.

METHOD

Electronic health records of children age 4-17 years who presented to the ED of a large academic medical center were analyzed using a natural language processing tool to estimate Research Domain Criteria (RDoC) symptom scores. These scores' association with length of stay and probability of admission versus discharge to home were evaluated.

RESULTS

We identified 3061 children and adolescents who presented to the ED and were evaluated by the psychiatry service between November 2008 and March 2015. Median length of stay was 7.8 h (interquartile range 5.2-14.3 h) and 1696 (55.4%) were admitted to the hospital. Higher estimated RDoC arousal, cognitive, positive, and social domain scores were associated with increased length of stay in multiple regression models, adjusted for age, sex, race, private insurance, voluntary admission, and diagnostic categories. In similarly adjusted models, odds of hospital admission were increased by higher RDoC arousal and cognitive domain scores and decreased by higher negative domain scores.

CONCLUSIONS

A natural language processing tool to characterize dimensional psychopathology identified features associated with differential outcomes in children in the psychiatric ED, most notably symptoms reflecting arousal and cognitive function. Methodologically, this in silico approach to risk stratification should facilitate precision psychiatry in children within the emergency setting.

Analysis of shared heritability in common disorders of the brain

Disorders of the brain can exhibit considerable epidemiological comorbidity and often share symptoms, provoking debate about their etiologic overlap. We quantified the genetic sharing of 25 brain disorders from genome-wide association studies of 265,218 patients and 784,643 control participants and assessed their relationship to 17 phenotypes from 1,191,588 individuals. Psychiatric disorders share common variant risk, whereas neurological disorders appear more distinct from one another and from the psychiatric disorders. We also identified significant sharing between disorders and a number of brain phenotypes, including cognitive measures. Further, we conducted simulations to explore how statistical power, diagnostic misclassification, and phenotypic heterogeneity affect genetic correlations. These results highlight the importance of common genetic variation as a risk factor for brain disorders and the value of heritability-based methods in understanding their etiology.

High Throughput Phenotyping for Dimensional Psychopathology in Electronic Health Records

BACKGROUND

Relying on diagnostic categories of neuropsychiatric illness obscures the complexity of these disorders. Capturing multiple dimensional measures of neuropathology could facilitate the clinical and neurobiological investigation of cognitive and behavioral phenotypes.

METHODS

We developed a natural language processing-based approach to extract five symptom dimensions, based on the National Institute of Mental Health Research Domain Criteria definitions, from narrative clinical notes. Estimates of Research Domain Criteria loading were derived from a cohort of 3619 individuals with 4623 hospital admissions. We applied this tool to a large corpus of psychiatric inpatient admission and discharge notes (2010-2015), and using the same cohort we examined face validity, predictive validity, and convergent validity with gold standard annotations.

RESULTS

In mixed-effect models adjusted for sociodemographic and clinical features, greater negative and positive symptom domains were associated with a shorter length of stay (β = -.88, p = .001 and β = -1.22, p < .001, respectively), while greater social and arousal domain scores were associated with a longer length of stay (β = .93, p < .001 and β = .81, p = .007, respectively). In fully adjusted Cox regression models, a greater positive domain score at discharge was also associated with a significant increase in readmission risk (hazard ratio = 1.22, p < .001). Positive and negative valence domains were correlated with expert annotation (by analysis of variance [df = 3], R² = .13 and .19, respectively). Likewise, in a subset of patients, neurocognitive testing was correlated with cognitive performance scores (p < .008 for three of six measures).

CONCLUSIONS

This shows that natural language processing can be used to efficiently and transparently score clinical notes in terms of cognitive and psychopathologic domains.

Subcortical brain volume differences in participants with attention deficit hyperactivity disorder in children and adults: a cross-sectional mega-analysis

BACKGROUND

Neuroimaging studies have shown structural alterations in several brain regions in children and adults with attention deficit hyperactivity disorder (ADHD). Through the formation of the international ENIGMA ADHD Working Group, we aimed to address weaknesses of previous imaging studies and meta-analyses, namely inadequate sample size and methodological heterogeneity. We aimed to investigate whether there are structural differences in children and adults with ADHD compared with those without this diagnosis.

METHODS

In this cross-sectional mega-analysis, we used the data from the international ENIGMA Working Group collaboration, which in the present analysis was frozen at Feb 8, 2015. Individual sites analysed structural T1-weighted MRI brain scans with harmonised protocols of individuals with ADHD compared with those who do not have this diagnosis. Our primary outcome was to assess case-control differences in subcortical structures and intracranial volume through pooling of all individual data from all cohorts in this collaboration. For this analysis, p values were significant at the false discovery rate corrected threshold of p=0·0156.

FINDINGS

Our sample comprised 1713 participants with ADHD and 1529 controls from 23 sites with a median age of 14 years (range 4-63 years). The volumes of the accumbens (Cohen's d=-0·15), amygdala (d=-0·19), caudate (d=-0·11), hippocampus (d=-0·11), putamen (d=-0·14), and intracranial volume (d=-0·10) were smaller in individuals with ADHD compared with controls in the mega-analysis. There was no difference in volume size in the pallidum (p=0·95) and thalamus (p=0·39) between people with ADHD and controls. Exploratory lifespan modelling suggested a delay of maturation and a delay of degeneration, as effect sizes were highest in most subgroups of children (<15 years) versus adults (>21 years): in the accumbens (Cohen's d=-0·19 vs -0·10), amygdala (d=-0·18 vs -0·14), caudate (d=-0·13 vs -0·07), hippocampus (d=-0·12 vs -0·06), putamen (d=-0·18 vs -0·08), and intracranial volume (d=-0·14 vs 0·01). There was no difference between children and adults for the pallidum (p=0·79) or thalamus (p=0·89). Case-control differences in adults were non-significant (all p>0·03). Psychostimulant medication use (all p>0·15) or symptom scores (all p>0·02) did not influence results, nor did the presence of comorbid psychiatric disorders (all p>0·5).

INTERPRETATION

With the largest dataset to date, we add new knowledge about bilateral amygdala, accumbens, and hippocampus reductions in ADHD. We extend the brain maturation delay theory for ADHD to include subcortical structures and refute medication effects on brain volume suggested by earlier meta-analyses. Lifespan analyses suggest that, in the absence of well powered longitudinal studies, the ENIGMA cross-sectional sample across six decades of ages provides a means to generate hypotheses about lifespan trajectories in brain phenotypes.

FUNDING

National Institutes of Health.

Extending the 'cross-disorder' relevance of executive functions to dimensional neuropsychiatric traits in youth

BACKGROUND

Evidence that different neuropsychiatric conditions share genetic liability has increased interest in phenotypes with 'cross-disorder' relevance, as they may contribute to revised models of psychopathology. Cognition is a promising construct for study; yet, evidence that the same cognitive functions are impaired across different forms of psychopathology comes primarily from separate studies of individual categorical diagnoses versus controls. Given growing support for dimensional models that cut across traditional diagnostic boundaries, we aimed to determine, within a single cohort, whether performance on measures of executive functions (EFs) predicted dimensions of different psychopathological conditions known to share genetic liability.

METHODS

Data are from 393 participants, ages 8-17, consecutively enrolled in the Longitudinal Study of Genetic Influences on Cognition (LOGIC). This project is conducting deep phenotyping and genomic analyses in youth referred for neuropsychiatric evaluation. Using structural equation modeling, we examined whether EFs predicted variation in core dimensions of the autism spectrum disorder, bipolar illness, and schizophrenia (including social responsiveness, mania/emotion regulation, and positive symptoms of psychosis, respectively).

RESULTS

We modeled three cognitive factors (working memory, shifting, and executive processing speed) that loaded on a second-order EF factor. The EF factor predicted variation in our three target traits, but not in a negative control (somatization). Moreover, this EF factor was primarily associated with the overlapping (rather than unique) variance across the three outcome measures, suggesting that it related to a general increase in psychopathology symptoms across those dimensions.

CONCLUSIONS

Findings extend support for the relevance of cognition to neuropsychiatric conditions that share underlying genetic risk. They suggest that higher-order cognition, including EFs, relates to the dimensional spectrum of each of these disorders and not just the clinical diagnoses. Moreover, results have implications for bottom-up models linking genes, cognition, and a general psychopathology liability.

Does developmental timing of exposure to child maltreatment predict memory performance in adulthood? Results from a large, population-based sample

Although maltreatment is a known risk factor for multiple adverse outcomes across the lifespan, its effects on cognitive development, especially memory, are poorly understood. Using data from a large, nationally representative sample of young adults (Add Health), we examined the effects of physical and sexual abuse on working and short-term memory in adulthood. We examined the association between exposure to maltreatment as well as its timing of first onset after adjusting for covariates. Of our sample, 16.50% of respondents were exposed to physical abuse and 4.36% to sexual abuse by age 17. An analysis comparing unexposed respondents to those exposed to physical or sexual abuse did not yield any significant differences in adult memory performance. However, two developmental time periods emerged as important for shaping memory following exposure to sexual abuse, but in opposite ways. Relative to non-exposed respondents, those exposed to sexual abuse during early childhood (ages 3-5), had better number recall and those first exposed during adolescence (ages 14-17) had worse number recall. However, other variables, including socioeconomic status, played a larger role (than maltreatment) on working and short-term memory. We conclude that a simple examination of "exposed" versus "unexposed" respondents may obscure potentially important within-group differences that are revealed by examining the effects of age at onset to maltreatment.

Prenatal antidepressant exposure is associated with risk for attention-deficit hyperactivity disorder but not autism spectrum disorder in a large health system

Previous studies suggested that risk for Autism Spectrum Disorder (ASD) may be increased in children exposed to antidepressants during the prenatal period. The disease specificity of this risk has not been addressed and the possibility of confounding has not been excluded. Children with ASD or attention-deficit hyperactivity disorder (ADHD) delivered in a large New England health-care system were identified from electronic health records (EHR), and each diagnostic group was matched 1:3 with children without ASD or ADHD. All children were linked with maternal health data using birth certificates and EHRs to determine prenatal medication exposures. Multiple logistic regression was used to examine association between prenatal antidepressant exposures and ASD or ADHD risk. A total of 1377 children diagnosed with ASD and 2243 with ADHD were matched with healthy controls. In models adjusted for sociodemographic features, antidepressant exposure prior to and during pregnancy was associated with ASD risk, but risk associated with exposure during pregnancy was no longer significant after controlling for maternal major depression (odds ratio (OR) 1.10 (0.70-1.70)). Conversely, antidepressant exposure during but not prior to pregnancy was associated with ADHD risk, even after adjustment for maternal depression (OR 1.81 (1.22-2.70)). These results suggest that the risk of autism observed with prenatal antidepressant exposure is likely confounded by severity of maternal illness, but further indicate that such exposure may still be associated with ADHD risk. This risk, modest in absolute terms, may still be a result of residual confounding and must be balanced against the substantial consequences of untreated maternal depression.

High loading of polygenic risk for ADHD in children with comorbid aggression

OBJECTIVE Although attention deficit hyperactivity disorder (ADHD) is highly heritable, genome-wide association studies (GWAS) have not yet identified any common genetic variants that contribute to risk. There is evidence that aggression or conduct disorder in children with ADHD indexes higher genetic loading and clinical severity. The authors examine whether common genetic variants considered en masse as polygenic scores for ADHD are especially enriched in children with comorbid conduct disorder. METHOD Polygenic scores derived from an ADHD GWAS meta-analysis were calculated in an independent ADHD sample (452 case subjects, 5,081 comparison subjects). Multivariate logistic regression analyses were employed to compare polygenic scores in the ADHD and comparison groups and test for higher scores in ADHD case subjects with comorbid conduct disorder relative to comparison subjects and relative to those without comorbid conduct disorder. Association with symptom scores was tested using linear regression. RESULTS Polygenic risk for ADHD, derived from the meta-analysis, was higher in the independent ADHD group than in the comparison group. Polygenic score was significantly higher in ADHD case subjects with conduct disorder relative to ADHD case subjects without conduct disorder. ADHD polygenic score showed significant association with comorbid conduct disorder symptoms. This relationship was explained by the aggression items. CONCLUSIONS Common genetic variation is relevant to ADHD, especially in individuals with comorbid aggression. The findings suggest that the previously published ADHD GWAS meta-analysis contains weak but true associations with common variants, support for which falls below genome-wide significance levels. The findings also highlight the fact that aggression in ADHD indexes genetic as well as clinical severity.

Genome-wide association study of the child behavior checklist dysregulation profile

OBJECTIVE

A potentially useful tool for understanding the distribution and determinants of emotional dysregulation in children is a Child Behavior Checklist profile, comprising the Attention Problems, Anxious/Depressed, and Aggressive Behavior clinical subscales (CBCL-DP). The CBCL-DP indexes a heritable trait that increases susceptibility for later psychopathology, including severe mood problems and aggressive behavior. We have conducted a genome-wide association study of the CBCL-DP in children with attention-deficit/hyperactivity disorder (ADHD).

METHOD

Families were ascertained at Massachusetts General Hospital and University of California, Los Angeles. Genotyping was conducted with the Illumina Human1M or Human1M-Duo BeadChip platforms. Genome-wide association analyses were conducted with the MQFAM multivariate extension of PLINK.

RESULTS

CBCL data were available for 341 ADHD offspring from 339 ADHD affected trio families from the UCLA (N = 128) and the MGH (N = 213) sites. We found no genome-wide statistically significant associations but identified several plausible candidate genes among findings at p < 5E-05: TMEM132D, LRRC7, SEMA3A, ALK, and STIP1.

CONCLUSIONS

We found suggestive evidence for developmentally expressed genes operant in hippocampal dependent memory and learning with the CBCL-DP.

Cognitive development in adults with attention-deficit/hyperactivity disorder: a controlled study in medication-naive adults across the adult life cycle

OBJECTIVE

This study evaluated the association between attention-deficit/hyperactivity disorder (ADHD) and psychometrically defined cognitive variables across the adult life span, using data from a large controlled study of adults with and without ADHD.

METHOD

Comparisons were made between 2 groups of adults: participants with DSM-IV-diagnosed ADHD who had never received pharmacotherapy for their ADHD (n = 116) and 146 control participants. Subjects received a battery assessing IQ, neuropsychological measures, and academic testing. We modeled cognitive measures as a function of age and group status using linear regression. The study was conducted at Massachusetts General Hospital, Boston, between 1998 and 2003.

RESULTS

ADHD and control subjects maintained similar, statistically significant differences in all psychometrically assessed measures of cognition within each decade that was represented (all P values < .01).

CONCLUSION

The negative impact of ADHD on multiple, nonoverlapping, psychometrically assessed measures of cognition remained constant across the life cycle, suggesting that the association between ADHD and cognition neither improves nor deteriorates across the life cycle.

Executive functioning in high-IQ adults with ADHD

BACKGROUND

To examine the association between psychological tests of executive functioning and functional outcomes among high-IQ adults with attention deficit hyperactivity disorder (ADHD).

METHOD

Subjects were high-IQ adults with (n=64) and without ADHD (n=53). Subjects were administered a battery of neuropsychological tests assessing executive functioning.

RESULTS

High-IQ adults with ADHD performed less well than those without ADHD on several psychological tests of executive functioning, including the Wisconsin Card Sorting Test (WCST), Stroop Color and Word Test, Rey-Osterrieth Complex Figure Test (ROCF), California Verbal Learning Test (CVLT) and an auditory continuous performance test (CPT). Test performance in the high-IQ adult ADHD group, however, was average. In the entire sample, performance on several tests of executive functioning including the ROCF and the CVLT were significant predictors of real-world functioning.

CONCLUSIONS

High-IQ adults with ADHD perform less well on tests of executive functioning relative to high-IQ control participants. Performance on several tests of executive functioning was a significant predictor of functioning.

Suggestive linkage of the child behavior checklist juvenile bipolar disorder phenotype to 1p21, 6p21, and 8q21

OBJECTIVE

Several studies have documented a profile of elevated scores on the Attention Problems, Aggressive Behavior and Anxious/Depressed scales of the Child Behavior Checklist (CBCL) in youth with bipolar disorder. The sum of these scales, referred to as the CBCL Juvenile Bipolar Disorder (JBD) phenotype, has modest diagnostic utility, and high scores are associated with severity of psychopathology and poor outcome. Recently, a genomewide linkage scan of this measure in ADHD sibling pairs revealed a region of suggestive linkage on chromosome 2q21. The current study aimed to further identify quantitative trait loci that influence the CBCL-JBD phenotype by using a dense and thus, arguably, more powerful set of single-nucleotide polymorphism markers in a different ADHD sibling pair sample.

METHOD

Subjects were 765 individuals from 154 families with CBCL data enrolled in a linkage study of ADHD. Linkage analyses were completed using a multipoint maximum likelihood variance components approach implemented using the statistical program SOLAR.

RESULTS

Heritability of the CBCL-JBD phenotype was estimated at .71. Although no regions of the genome surpassed empirically derived criteria for significant linkage (p = .000038), peaks on 1p21.1 (p = .00037; LOD = 2.76), 6p21.3 (p = .00054; LOD =2.60), and 8q21.13 (p = .00081; LOD = 2.44) surpassed the threshold for suggestive linkage (p = .002). These regions have been highlighted in genomewide scans of bipolar disorder in adults, schizophrenia, autism, and ADHD.

CONCLUSIONS

Findings raise the possibility that genes in these regions influence variation on the CBCL-JBD scale and the emotional and behavioral dysregulation associated with severe psychopathology.

Effect of dopamine transporter gene (SLC6A3) variation on dorsal anterior cingulate function in attention-deficit/hyperactivity disorder

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.

Effect of candidate gene polymorphisms on the course of attention deficit hyperactivity disorder

The main aim of this study was to examine the association between attention-deficit hyperactivity disorder (ADHD)-associated genes and the course of ADHD. Subjects were derived from identically designed case-control family studies of boys and girls with ADHD and a genetic linkage study of families with children with ADHD. Caucasian probands and family members with ADHD and with available genetic data were included in this analysis (N=563). The course of ADHD was compared in subjects with and without putative risk alleles (DRD4 7-repeat allele, DAT1 10-repeat allele, and 5HTTLPR long allele). The persistence of ADHD (full or subthreshold diagnosis in the last month) was plotted using Kaplan-Meier survival functions and tested with Cox proportional hazard models. Survival analyses revealed that by 25 years of age 76% of subjects with a DRD4 7-repeat allele were estimated to have significantly more persistent ADHD compared with 66% of subjects without the risk allele. In contrast, there were no significant associations between the course of ADHD and the DAT1 10-repeat allele (P=0.94) and 5HTTLPR long allele. Our findings suggest that the DRD4 7-repeat allele is associated with a more persistent course of ADHD.

Evidence for genetic association of RORB with bipolar disorder

BACKGROUND

Bipolar disorder, particularly in children, is characterized by rapid cycling and switching, making circadian clock genes plausible molecular underpinnings for bipolar disorder. We previously reported work establishing mice lacking the clock gene D-box binding protein (DBP) as a stress-reactive genetic animal model of bipolar disorder. Microarray studies revealed that expression of two closely related clock genes, RAR-related orphan receptors alpha (RORA) and beta (RORB), was altered in these mice. These retinoid-related receptors are involved in a number of pathways including neurogenesis, stress response, and modulation of circadian rhythms. Here we report association studies between bipolar disorder and single-nucleotide polymorphisms (SNPs) in RORA and RORB.

METHODS

We genotyped 355 RORA and RORB SNPs in a pediatric cohort consisting of a family-based sample of 153 trios and an independent, non-overlapping case-control sample of 152 cases and 140 controls. Bipolar disorder in children and adolescents is characterized by increased stress reactivity and frequent episodes of shorter duration; thus our cohort provides a potentially enriched sample for identifying genes involved in cycling and switching.

RESULTS

We report that four intronic RORB SNPs showed positive associations with the pediatric bipolar phenotype that survived Bonferroni correction for multiple comparisons in the case-control sample. Three RORB haplotype blocks implicating an additional 11 SNPs were also associated with the disease in the case-control sample. However, these significant associations were not replicated in the sample of trios. There was no evidence for association between pediatric bipolar disorder and any RORA SNPs or haplotype blocks after multiple-test correction. In addition, we found no strong evidence for association between the age-at-onset of bipolar disorder with any RORA or RORB SNPs.

CONCLUSION

Our findings suggest that clock genes in general and RORB in particular may be important candidates for further investigation in the search for the molecular basis of bipolar disorder.

Neurocognitive impairment in unaffected siblings of youth with bipolar disorder

BACKGROUND

There is growing evidence for the familiality of pediatric bipolar disorder (BPD) and its association with impairments on measures of processing speed, verbal learning and 'executive' functions. The current study investigated whether these neurocognitive impairments index the familial risk underlying the diagnosis.

METHOD

Subjects were 170 youth with BPD (mean age 12.3 years), their 118 non-mood-disordered siblings and 79 non-mood-disordered controls. Groups were compared on a battery of neuropsychological tests from the Wechsler Intelligence Scales, the Stroop Color Word Test, the Wisconsin Card Sorting Test (WCST), the Rey-Osterrieth Complex Figure (ROCF), an auditory working memory Continuous Performance Test (CPT) and the California Verbal Learning Test-Children's Version (CVLT-C). Measures were factor analyzed for data reduction purposes. All analyses controlled for age, sex and attention-deficit/hyperactivity disorder (ADHD).

RESULTS

Principal components analyses with a promax rotation yielded three factors reflecting: (1) processing speed/verbal learning, (2) working memory/interference control and (3) abstract problem solving. The CPT working memory measure with interference filtering demands (WM INT) was only administered to subjects aged > or =12 years and was therefore analyzed separately. BPD youth showed impairments versus controls and unaffected relatives on all three factors and on the WM INT. Unaffected relatives exhibited impairments versus controls on the abstract problem-solving factor and the WM INT. They also showed a statistical trend (p=0.07) towards worse performance on the working memory/interference control factor.

CONCLUSIONS

Neurocognitive impairments in executive functions may reflect the familial neurobiological risk mechanisms underlying pediatric BPD and may have utility as endophenotypes in molecular genetic studies of the condition.

Linkage analysis of attention deficit hyperactivity disorder

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.

Sexually dimorphic effects of four genes (COMT, SLC6A2, MAOA, SLC6A4) in genetic associations of ADHD: a preliminary study

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.

A preliminary study of dopamine D4 receptor genotype and structural brain alterations in adults with ADHD

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.

Multivariate genomewide linkage scan of neurocognitive traits and ADHD symptoms: suggestive linkage to 3q13

Family and twin studies suggest that a range of neurocognitive traits index the inherited liability to ADHD; however, the utility of such measures as endophenotypes in molecular genetic studies remains largely untested. The current article examined whether the inclusion of neurocognitive measures in a genomewide linkage analysis of ADHD could aid in identifying QTL linked to the behavioral symptoms of the condition. Data were from an affected sibling pair linkage study of DSM-IV ADHD conducted at Massachusetts General Hospital. The sample included 1,212 individuals from 271 families. ADHD symptoms were assessed with the K-SADS-E. The neurocognitive battery included Wechsler Intelligence Scales subtests, the Stroop, the Wisconsin Card Sorting Test (WCST), the Rey-Osterreith Complex Figure, a working memory CPT, the CVLT and WRAT-III subscales. Evidence for linkage was assessed using a simulation-based method that combines information from univariate analyses into the equivalent of a multivariate test. After correction for multiple trait testing, a region on chromosome 3q13 showed suggestive linkage to all neurocognitive traits examined and inattention symptoms of ADHD. The second highest peak occurred on 22q12 but showed linkage to a single subscale of the WCST. In univariate analysis, this region retained criteria for suggestive linkage to this measure after correction for multiple trait testing. Our primary findings raise the possibility that one or more genes on 3q13 influence neurocognitive functions and behavioral symptoms of inattention. Overall, these data support the utility of neurocognitive traits as ADHD endophenotypes, but also highlight their limited genetic overlap with the disorder.

Educational and occupational underattainment in adults with attention-deficit/hyperactivity disorder: a controlled study

OBJECTIVE

Attention-deficit/hyperactivity disorder (ADHD) has been consistently associated with intellectual, educational, and employment deficits. This study evaluated subjects to determine whether the educational and occupational deficits associated with ADHD are what would be expected given their intellectual abilities or lower than expected given their intellectual abilities.

METHOD

Participants derived from a case-control study of adults with (N = 224) and without (N = 146) DSM-IV ADHD. Subjects were comprehensively assessed with structured diagnostic interviews and neuropsychological assessments. Educational and occupational attainments were based on Hollingshead socioeconomic status scale. The expected educational and occupational levels of participants with ADHD were computed using ordered logistic regression models as a function of age, sex, and full scale IQ of controls. The study was conducted from 1998 to 2003.

RESULTS

Based on their IQ, subjects with ADHD were predicted to have significantly more education than they actually attained. Additionally, based on their observed education, participants with ADHD were predicted to have significantly higher occupational levels than actually observed.

CONCLUSION

These findings indicate that ADHD is associated with significant educational and occupational underattainments relative to what would have been expected on the basis of intellectual potential.

Effects of stimulant medication on neuropsychological functioning in young adults with attention-deficit/hyperactivity disorder

OBJECTIVE

The main goal of this study was to evaluate the impact of stimulant medication on executive function deficits in a group of adolescents and young adults with attention-deficit/hyperactivity disorder (ADHD; DSM-III-R criteria).

METHOD

Male and female subjects aged 15 to 25 years were divided into 3 groups: subjects with ADHD treated with stimulants who took their medication at the time of testing (ADHD active stimulant treatment: N = 26), subjects with ADHD who had not taken stimulant medication in the past month (ADHD no stimulant treatment: N = 94), and non-ADHD control subjects (controls: N = 133). The neuropsychological battery assessed domains of cognitive functioning known to be relevant in ADHD, including tests of executive functions and learning and memory. Data were collected from July 1998 to April 2003.

RESULTS

The ADHD no stimulant treatment group had significantly lower aggregate scores compared with the controls for the total aggregate, working memory, interference control, processing speed, sustained attention, and verbal learning domains (all p < .001). The ADHD active stimulant treatment group had significantly poorer scores on the total aggregate (p = .002), interference control (p < .001), and processing speed (p = .003) domains compared with the controls. The ADHD active stimulant treatment subjects scored significantly higher on the domains of sustained attention (p = .04) and verbal learning (p = .03) compared with the ADHD no stimulant treatment subjects.

CONCLUSIONS

Our study showed that subjects with ADHD who took stimulant medication had higher neuropsychological measures of attention compared with subjects with ADHD who did not take stimulant medication, but differences were not found for other measures of executive function.

Discordance between psychometric testing and questionnaire-based definitions of executive function deficits in individuals with ADHD

OBJECTIVE

One suspected source of negative outcomes associated with ADHD has been deficits in executive functions. Although both psychometrically defined and self-reported executive function deficits (EFDs) have been shown to be associated with poor academic and occupational outcomes, whether these two approaches define the same individuals remains unknown.

METHOD

Participants were 194 adults with ADHD from a case-control study of ADHD. Empirically based cutoffs were ascertained for an EFD diagnosis on both psychometric tests and scores on the Current Behavior Scale.

RESULTS

Results showed a modest overlap between the psychometric and self-reported definitions of EFDs. Whereas neuropsychological testing largely identified individuals with lower IQ and achievement testing, the behavioral questionnaire largely identified individuals with higher levels of ADHD symptoms, psychiatric comorbidity, and interpersonal deficits.

CONCLUSION

Results indicate that behavioral questionnaires cannot be used interchangeably with neuropsychological testing for the assessment of EFDs in adults with ADHD.