title: Continued cannabis use and outcome in first-episode psychosis: data from a randomized, open-label, controlled trial.
abstract: OBJECTIVE
  Cannabis use has been found to increase the risk of psychosis. It is unclear whether, after a first psychotic episode has occurred, continued cannabis use is associated with poor functional outcome of psychosis.
  
  
  METHODS
  As part of a randomized, open-label, controlled trial, the association of cannabis use and measures for psychopathology and social role functioning after 2 years of follow-up and for the recently proposed outcome measures of symptomatic remission, functional remission, and clinical recovery was explored in a group of 124 patients suffering from nonaffective first-episode psychosis (diagnosed according to DSM-IV and included from a catchment area in the Netherlands of 3.1 million inhabitants from October 2001 through December 2002). Other patient characteristics that were expected to be independently associated with outcome, among them alcohol and other drug use, were assessed at baseline.
  
  
  RESULTS
  Continued cannabis use was not associated with symptomatic or functional remission or clinical recovery. After 2 years, cannabis use was related to certain aspects of social role functioning (economic and social activities; explained variance 5.6% and 8.4%, respectively) but not to psychopathology (Positive and Negative Syndrome Scale Positive, Negative, or General symptoms).
  
  
  CONCLUSIONS
  Our findings support the notion that continued cannabis use after the onset of a first-episode psychosis is correlated with worse social outcome and should be discouraged whenever possible, but its role in outcome is modest in comparison to other factors.
  
  
  BACKGROUND
  Nederlands Trial Register: http://www.trialregister.nl (ID: NTR 374).
authors.affiliation: Yulius, Mental Health Institute, Dordrecht, The Netherlands. g.faber@yulius.nl
authors.forename: Gunnar
authors.initials: G
authors.lastname: Faber
authors.forename: Henderikus G O M
authors.initials: HG
authors.lastname: Smid
authors.forename: Arthur R
authors.initials: AR
authors.lastname: Van Gool
authors.forename: Lex
authors.initials: L
authors.lastname: Wunderink
authors.forename: Robert J
authors.initials: RJ
authors.lastname: van den Bosch
authors.forename: Durk
authors.initials: D
authors.lastname: Wiersma
mesh_terms: D000293:Adolescent; D000328:Adult; D017831:Diagnosis, Dual (Psychiatry); D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D016013:Likelihood Functions; D008297:Male; D008385:Marijuana Smoking / Q000517:prevention & control / Q000523:psychology*; D008875:Middle Aged; D015999:Multivariate Analysis; D009426:Netherlands; D011379:Prognosis; D011618:Psychotic Disorders / Q000523:psychology / Q000534:rehabilitation*; D016032:Randomized Controlled Trials as Topic; D020127:Recovery of Function; D012559:Schizophrenia / Q000534:rehabilitation*; D012565:Schizophrenic Psychology; D012917:Social Adjustment