Table 1.
Studies suggesting an association between cannabis use and psychosis.
| Study | N | Design | Prevalence/use of cannabis | Outcome | Adjusted risk |
|---|---|---|---|---|---|
| Andreasson et al. (1987) | 45,570 | Longitudinal conscript cohort (Sweden) | >50 times | Hospitalization | 2.3 |
| Arseneault et al. (2002) | 759 | Prospective birth cohort (Dunedin) | Lifetime | Any schizophreniform Disorders | 3.1 |
| Van Os et al. (2002) | 4095 | Longitudinal population-based (Netherlands) | Lifetime | Any psychotic symptom | 2.8 |
| Fergusson et al. (2003) | 1011 | Birth cohort (Christchurch) | DSM-IV dependence | Any psychotic symptom | 1.8 |
| Zammit et al. (2002) | 50,087 | Longitudinal conscript cohort (Sweden) | >50 times | Hospitalization | 3.1 |
| Henquet et al. (2005) | 3467 | Prospective cohort (Germany) | Lifetime | Any psychotic symptom | 1.7 |
| Di Forti et al. (2009) | 280 | Case–control (UK) | Lifetime | First-episode psychosis | 6.8 (skunk users) |
| Mc Grath et al. (2010) | 3801 | Prospective cohort (Australia) | ≥6 years duration | Non-affective psychosis | 2.1 |