Our pleiotropy analysis showed genetic overlap between stimulant dependence and alcohol use disorder, anxiety, and ADHD. Stimulants are widely used as a treatment for ADHD18, however there is disagreement about whether prescribing amphetamine for ADHD increases the risk of substance abuse in adulthood60–62. Studies of an ancestrally diverse set of cohorts (Thai, Malaysian, American, Chinese, and Australian)25,63–67 have demonstrated high comorbidity between psychiatric disorders including major depressive disorder26,64, anxiety disorder26,65 and alcohol use disorder26,65 in amphetamine-informative cohorts. It is not surprising that in our study individual variants associated with stimulant dependence also affected the risk of alcohol dependence and anxiety in EAs but not AAs because the GWAS summary data for these other disorders were derived primarily from EA cohorts.
