Relationship of Major Depressive Disorder and Schizophrenia Polygenic Risk Scores to Suicide: A Comparison Between European and Asian Ancestry Populations

Psychiatric diagnosis rates in suicide decedents appear higher in European ancestry populations compared with East Asians. Shared genetic components exist between major depressive disorder (MDD)/schizophrenia (SCZ) and suicide, but no study has compared these shared polygenic architectures between Europeans and East Asians. We compared polygenic risk scores (PRSs) for MDD/SCZ determined from large data sets specific to each ancestry in European and East Asian suicide decedent samples. MDD/SCZ PRSs appeared more prominent in European suicides compared with Japanese suicides. A greater coexistence of psychiatric disorders in European suicide decedents than in East Asian suicide decedents may be partly explained by genetics. Our results are limited by the smaller sample size of our suicide decedents and sample size disparities between the European discovery data set and the East Asian data set for MDD/SCZ, resulting in less statistical power to detect robust difference between the two ancestries. Psychiatric diagnosis in suicides appears more common in Europeans than in East Asians.This is the first comparison of suicide genome-wide association studies between Europeans and East Asians.Major depressive disorder/schizophrenia polygenic risk scores for suicide were more significant for Europeans than for East Asians.