Zhou H, et al. - Genetic risk variants for comorbid alcohol dependence (AD) and major depression (MD) were detected. Furthermore, the authors determined whether polygenic risk alleles were shared with neuropsychiatric traits or subcortical brain volumes. In African American participants, SEMA3A variation was significantly and replicably associated with comorbid AD and MD. Analyses of polygenic risk scores identified pleiotropy with neuropsychiatric traits and brain volumes. To understand the biological and genetic mechanisms of this comorbidity, further studies were warranted, which could facilitate development of medications and other treatments for comorbid AD and MD.