The number of independent multiple tests across the six primary phenotypes (alcohol use, MAXD, SRE-T, DSM4AD, DSM5AUDSX, and reduction/cessation) was estimated by identifying the degree of phenotypic correlation across the measures of drinking using spectral decomposition of the data in matSpD (Nyholt, 2004). Five independent tests were estimated (Veff = 4.82). Thus, for the first set of analyses, where PRS (including 9 p-value thresholds) predicted measures of drinking, we corrected for 45 tests (9 PRS thresholds for each of 5 independent phenotypic tests), for a Bonferroni-corrected p value of 0.05/45 = 1.1e-03. For follow-up analyses (e.g., adjustment for rs1229984), where only a single PRS at one p-value threshold was used, a less stringent correction of 0.05/5=0.01 was implemented.
