Polygenic Risk Scores for Psychiatric Disorders Reveal Novel Clues About the Genetics of Disordered Gambling

Abstract

Background and Aims: Twin studies indicate that disordered gambling (DG) is heritable but are silent with respect to specific genes or pathways involved. Genome-wide association studies of other psychiatric disorders permit calculation of polygenic risk scores (PRS) that reflect the aggregated effects of common genetic variants contributing to risk for the target condition. We investigated whether gambling and DG are associated with PRSs for four psychiatric conditions found to be comorbid with DG in epidemiologic surveys. Design and Setting: Data were drawn from the Wave IV assessment of the National Longitudinal Study of Adolescent to Adult Health, a representative sample of adolescents recruited in 1994-5 and followed into young adulthood. Participants: Analyses were limited to unrelated individuals classified as having European ancestry based on analysis of genetic principal components (N = 5,215). Measurements: Participants were surveyed about lifetime gambling and DG. Genotyping data were used to construct PRSs quantifying participants’ common variant genetic risk for major depression (MDD), attention-deficit hyperactivity disorder (ADHD), bipolar disorder (BD), and schizophrenia (SCZ). Findings: Most participants (78.4%) reported ever having gambled, and 1.3% of those reported lifetime DG. Polygenic risk for BD was associated with decreased odds of lifetime gambling, OR = 0.93 [0.87, 0.99], p = .045, pseudo-R2(%) = 0.12. The SCZ PRS was associated with increased odds of DG, OR = 1.54 [1.07, 2.21], p = .020, pseudo-R2 (%) = 0.85. Polygenic risk for MDD and ADHD were not related to either gambling outcome. Conclusions: Common variant risk for SCZ is associated with DG. Investigating features common to both SCZ and DG might generate valuable clues about the genetically-influenced liabilities to DG.