A PRS analysis was conducted to test the genetic overlap with behavioral traits that could differentiate between OD and OE status using the PRSice software33. Risk-taking and neuroticism were selected as we expected they would capture genetic susceptibility to early versus later stages of opioid use and misuse. For polygenic profile scoring, we used summary statistics generated from large-scale GWAS of risk tolerance (N= 466,571)34 and neuroticism (N=390,278)35. We considered multiple association P value thresholds (PT < 5×10−8, 10−7, 10−6, 10−5, 10−4, 0.001, 0.05, 0.1, 0.3, 0.5, 1) for SNP inclusion to identify the best-fit for each target phenotype tested. The PRS were calculated after using P-value-informed clumping with a LD cut-off of R2 = 0.3 within a 500 kb window and excluding the major histocompatibility complex region of the genome because of its complex LD structure. The PRS were calculated considering unrelated subjects of European descent available in both case-control and family-based cohorts (ODexposed Neffective=3,038; ODunexposed Neffective=4,728; and OEcontrols Neffective=5,376). The PRS were fitted in regression models with adjustments for sex and the top 10 within-ancestry principal components. We applied FDR multiple testing correction (q<0.05) to correct for the number of thresholds tested.
