Table 1.
Gene × cannabis interactions in moderating risk of psychosis.
| Gene/locus | Study | Study design | Sample size | Follow up | Outcome – odds ratio (OR)/relative risk (RR) |
|---|---|---|---|---|---|
| COMT/rs4680 | Caspi et al. (200) | Longitudinal, prospective (Dunedin cohort) | 803 | 26 years | OR 10.9 (95% CI 2.2–54.1) of developing psychotic disorder in Val/Val genotype |
| OR 2.5 (95% CI 0.78–8.2) of developing psychotic disorder in Val/Met allele | |||||
| OR 1.1 (95% CI 0.21–5.4) of developing psychotic disorder in Met/Met allele | |||||
| COMT/rs4680 | Zammit et al. (281) | Case-only, cross-sectional analysis | 493 | NA | OR 0.98 (95% CI 0.76–1.27) for history of cannabis use in schizophrenia subjects with Val/Val allele |
| COMT/rs4680 | Zammit et al. (282) | Longitudinal (Avon cohort) | 2630 | 2 years | OR 1.0 (95% CI 0.73–1.36) of cannabis × COMT interaction |
| OR 1.56 (95% CI 1.05–2.31) of psychosis in cannabis users with Met/Met genotype | |||||
| OR 1.47(95% CI 0.85–2.26) of psychosis in cannabis users with Val/Val genotype | |||||
| OR 1.68 (95% CI 1.23–2.28) of psychosis in cannabis users with Met/Val genotype | |||||
| COMT/rs4680 | Costas et al. (283) | Case-only, cross-sectional analysis | 748 | NA | OR 2.07 (95% CI 1.27–3.26) of history of cannabis use in schizophrenia pts w/Met/Met genotype vs. Val/Val genotype |
| AKT1/rs2494732 | van Winkel (284) | Cross-sectional analysis | 801 Subjects with psychosis | NA | RR 1.90 (p < 0.01) of C/C genotype in daily cannabis users – case-only analysis |
| 740 Unaffected siblings | OR 1.96 (95% CI 1.09–3.53) of being diagnosed with psychotic disorder in C/C allele subjects – case–sibling analysis | ||||
| 419 Controls | OR 2.08 (95% CI 0.92–4.67) of being diagnosed with psychotic disorder in C/C allele subjects – case–control analysis | ||||
| AKT1/rs2494732 | Di Forti et al. (285) | Case–control, cross-sectional analysis | 489 Subjects | NA | OR 7.23 (95% CI 1.37–38.12) of psychotic disorder in C/C genotype subjects with daily cannabis use vs. T/T genotype |
| 278 Controls | OR 2.18 (95% CI 1.12–4.31) of psychotic disorder in C/C genotype subjects with history of cannabis use |
OR, odds ratio; RR, relative risk; CI, confidence interval.