While no genes were associated with AD and OD after multiple-testing correction, 9 genes were significantly associated with life-time cannabis use: LRRTM4 (P = 4.51 × 10−7), CADM2 (P = 1.14 × 10−13), AS3MT (P = 9.43 × 10−7), NCAM1 (P = 1.44 × 10−9), ATXN2L (P = 1.85 × 10−8), TUFM (P = 5.72 × 10−8), SH2B1 (P = 3.15 × 10−8), ATP2A1 (P = 1.68 × 10−8), RABEP2 (P = 1.64 × 10−6), and SRR (P = 1.61 × 10−6) (Supplementary Table 5) with none of these genes shared with CUD. This evidence concerns the gene NCAM1 and Alzheimer disease.