Can polygenic risk scores help identify pediatric bipolar spectrum and related disorders?: A systematic review

The genetic basis of mood disorders can, theoretically, provide diagnostic information in scenarios of clinical uncertainty. Therefore, we examined the available body of knowledge on the association between polygenic risk scores for bipolar disorder (BP-PRSs) and pediatric bipolar spectrum and related disorders. We performed a literature search through PubMed in March of 2020. The following variables were extracted from relevant studies: population age, study sample size, source of polygenic risk scores, source of data, the primary goal of the study, the assessments used during the course of the study, and the main findings/outcomes of each study. BP-PRSs were associated with deficits in executive functioning and the diagnosis of attention deficit/hyperactivity disorder (ADHD). Three studies included in our analysis directly compared major depressive disorder (MDD)-PRSs to BP-PRSs in youth. Results showed that MDD-PRSs, and not BP-PRSs, were associated with ADHD symptoms, internalizing problems, and social problems. ADHD-PRSs were associated with conduct problems, depressive symptomatology, and externalizing disorders symptoms. Findings revealed that ADHD-PRSs were more clearly associated with emotional reactivity, emotional dysregulation, and irritability-frequent correlates of pediatric BP disorder. These findings suggest that ADHD-PRSs may have an important contribution to the development of mood related problems in youth.