INTERPRETATION Continued cannabis use after onset of psychosis predicts adverse outcome , including higher relapse rates , longer hospital admissions , and more severe positive symptoms than for individuals who discontinue cannabis use and those who are non-users .
BACKGROUND Although the link between cannabis use and development of psychosis is well established , less is known about the effect of continued versus discontinued cannabis use after the onset of psychosis .
We aim ed to summarise available evidence focusing on the relationship between continued and discontinued cannabis use after onset of psychosis and its relapse .
Continued cannabis use and outcome in first-episode psychosis: data from a randomized, open-label, controlled trial.
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 . METHOD As part of a r and omized , 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 Netherl and s 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 . TRIAL REGISTRATION Nederl and s Trial Register : http://www.trialregister.nl ( ID : NTR 374 )
INTERPRETATION Continued cannabis use after onset of psychosis predicts adverse outcome , including higher relapse rates , longer hospital admissions , and more severe positive symptoms than for individuals who discontinue cannabis use and those who are non-users .
BACKGROUND Although the link between cannabis use and development of psychosis is well established , less is known about the effect of continued versus discontinued cannabis use after the onset of psychosis .
We aim ed to summarise available evidence focusing on the relationship between continued and discontinued cannabis use after onset of psychosis and its relapse .