The study included 6217 individuals who were in the Swedish criminal justice system from 2001 to 2006. The purpose of this study was to determine long-term risk factors for substance-induced and primary psychosis after release from prison.
Polydrug use was the strongest predictor for substance-induced psychosis but all substances imposed an increased risk. Previous psychiatric hospitalization and non-drug related hallucinations were significant, but weaker, risk factors. The only substance variable that predicted primary psychosis was cannabis but previous psychiatric hospitalization and non-drug related hallucinations were even stronger predictors.
The study shows that cannabis use was a risk factor for primary psychosis, but other health related individual risk factors were even more important. Polydrug use was the strongest risk factor for substance-induced psychosis.
Read the full article in Schizophrenia Research