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 .
Effect of cannabis use on the course of schizophrenia in male patients: A prospective cohort study
BACKGROUND Findings on the impact of cannabis use on the course of schizophrenia are inconsistent and not conclusive . AIMS To study the effect of cannabis use on the course of schizophrenia taking into account the effects of the quantity of cannabis use and important confounders . METHODS Prospect i ve cohort study with assessment s of symptoms , confounders and hospitalizations at baseline , 6 month and 12 month follow up . RESULTS In a representative cohort of 145 male patients with schizophrenia , 68 ( 46.9 % ) used cannabis .  Mean age at onset of schizophrenia in cannabis using patients was significantly lower than in non-cannabis using patients . No other cross-sectional demographic or clinical differences were observed between users and non-users . In a series of longitudinal analyses , cannabis use was not associated with differences in psychopathology , but relapse in terms of the number of hospitalizations was significantly higher in cannabis using patients compared to non-cannabis using patients . CONCLUSIONS Patients with schizophrenia using cannabis are more frequently hospitalized than non-cannabis using patients but do not differ with respect to psychopathology . Possible explanations for these findings are discussed
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 .