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 (ß 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.

Characteristics of Child Psychiatric Outpatients at Highest Risk for Suicidal Thoughts and Behaviors.

On average, compared to non-referred youth, child psychiatric outpatients show elevated rates of suicidal thoughts and behaviors (STBs), which are predictors of completed suicide. Determining the psychopathology features that associate with highest risk for STBs among youth outpatients may yield opportunities for targeted prevention/intervention. Yet, outpatient studies are limited and have not systematically examined comorbidity and dimensional psychopathology. In 758 youth, aged 6-18, consecutively referred for neuropsychiatric evaluation, we examined the extent to which diagnostic groups, comorbid subgroups and dimensional symptoms associated with STBs. After controlling for comorbidity, mood, anxiety and conduct disorders associated with elevated STB risk. Regarding dimensions, symptoms of depression, aggression and psychosis all contributed to higher STB risk. Although ADHD (as a diagnosis or dimension) did not associate with elevated STB risk independently, ADHD that was comorbid with other conditions did. Suicide prevention/intervention efforts should be investigated in youth outpatients with the highest risk for STBs.