These findings add important nuance to discussions regarding the nature of associations between educational attainment and problematic substance use. First, our findings are consistent with previous findings that educational outcomes reflect many genetically influenced traits and behaviors, including SUD-associated factors like behavior problems, attention-deficit hyperactivity disorder, and personality [25, 26, 47–50], not simply intelligence or cognitive ability. Interestingly, in our robustness analyses, the educational attainment polygenic scores predicted alcohol use disorder and nicotine dependence criterion counts above and beyond participants’ observed (phenotypic) educational attainment. This highlights that these polygenic scores index factors linked to educational persistence and SUDs that are not fully captured by educational attainment itself. In contrast, for cannabis, the educational attainment polygenic score did not have unique predictive power above and beyond the educational attainment phenotype.
