title: Long-term risk factors for substance-induced and primary psychosis after release from prison. A longitudinal study of substance users.
abstract: OBJECTIVE
  The purpose of this study was to determine long-term risk factors for substance-induced and primary psychosis after release from prison.
  
  
  METHODS
  We used a longitudinal register-based cohort study combining European version of Addiction Severity Index (Europ-ASI) interviews and the Swedish inpatient register. The study included 6217 individuals who were in the Swedish criminal justice system from 2001 to 2006.
  
  
  METHODS
  The outcomes were substance-induced and primary psychosis as defined by the International Classification of Disease - 10th version. All variables for estimating baseline risk were drawn from the Europ-ASI interview, and included information on substance use, demographics and health. The interview database and the inpatient register were coupled, and groups were compared by using tests of significance and logistic regression.
  
  
  RESULTS
  Polydrug use was the strongest predictor for substance induced psychosis (OR=9.55, 95% CI 3.42-26.67), 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 (OR=2.62, 95% CI 1.39-4.96), but previous psychiatric hospitalization (OR=3.22, 95% CI 2.27-4.54) and non-drug related hallucinations (OR=4.00, 95% CI 2.82-5.67) were even stronger predictors.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Norwegian Centre for Addiction Research (SERAF), University of Oslo, Address: Box 1039 Blindern, 0315 Oslo, Norway; Division of Mental Health and Addiction, Oslo University Hospital, Address: Box 4950 Nydalen, 0424 Oslo, Norway; Norwegian National Advisory Unit on Concurrent Substance Abuse and Mental Health Disorders, Address: Box 104, 2381 Brumunddal, Norway. Electronic address: e.b.rognli@medisin.uio.no.
authors.forename: Eline Borger
authors.initials: EB
authors.lastname: Rognli
authors.affiliation: Department of Clinical Sciences Lund, Division of Psychiatry, Lund University, Address: Box 117, 221 00 Lund, Sweden.
authors.forename: Jonas
authors.initials: J
authors.lastname: Berge
authors.affiliation: Department of Clinical Sciences Lund, Division of Psychiatry, Lund University, Address: Box 117, 221 00 Lund, Sweden.
authors.forename: Anders
authors.initials: A
authors.lastname: Håkansson
authors.affiliation: Norwegian Centre for Addiction Research (SERAF), University of Oslo, Address: Box 1039 Blindern, 0315 Oslo, Norway.
authors.forename: Jørgen G
authors.initials: JG
authors.lastname: Bramness
mesh_terms: D000328:Adult; D057237:Criminals / Q000706:statistics & numerical data; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007406:Interview, Psychological; D008137:Longitudinal Studies; D008297:Male; D002189:Marijuana Abuse / Q000453:epidemiology; D008875:Middle Aged; D011329:Prisoners / Q000706:statistics & numerical data*; D011605:Psychoses, Substance-Induced / Q000453:epidemiology*; D011618:Psychotic Disorders / Q000453:epidemiology*; D012042:Registries; D012307:Risk Factors; D012720:Severity of Illness Index; D013548:Sweden / Q000453:epidemiology; D055815:Young Adult
keywords: Cannabis; Drugs; Prison; Psychosis; Schizophrenia; Substance use