Because there was significantly more males among patients with marijuana misuse (92.3% versus 69.4% in patients without marijuana misuse), we repeated the statistical analyses using only male subjects. Genotype effects on WM brain volumes and on neurocognition among males were similar to those using the entire study sample (data available upon request). As an alternative to single-marker analyses, we conducted exploratory haplotype analyses (see Supplementary Information). Haplotype-based findings were consistent with those from single-marker tests.
