MDD PRS were associated with increased alcohol, cocaine, and nicotine involvement, as well as with multiple levels of cannabis involvement (Supplementary Table S5). Associations with non-problem cannabis use and severe cocaine dependence remained significant following correction for multiple tests. Alcohol: MDD PRS were associated with moderate and severe alcohol dependence relative to no/non-regular use and lesser levels of involvement. Cannabis: Higher MDD PRS differentiated cannabis users with 0, 3–5, and 6–7 dependence symptoms from non-users. Cocaine: Compared with non-users and non-problem users, those with severe cocaine dependence had higher MDD PRS. Nicotine: MDD PRS were associated with moderate and severe nicotine dependence relative to non-regular use and lower levels of involvement.
