Risperidone compared to haloperidol in cannabis-induced psychotic disorder: A double blind randomized controlled trial

INTRODUCTION: Few controlled data exist on the treatment of substance-induc ed psychotic disorders, Our aim was to investigate the effects of risperidi one and haloperidol. METHOD: 30 patients who met DSM-IV criteria for cannabis-induced psychotic disorder were randomly allocated to receive either risperidone or haloperid ol in a 4-week randomized controlled double-blind clinical trial. RESULTS: There were no significant outcome differences between the two grou ps on any of the primary outcome measures, the Brief Psychiatric Rating Sca le, Clinical Global Impression scale or the Global Assessment of Functionin g Scale. No extrapyramidal sine-effects (EPS), as measured by either the Si mpson Angus Scale or the Barnes Akathisia Scale, emerged in the risperidone group; this was however not statistically different to the haloperidol gro up due to the low rate of EPS in that group. There were no significant diff erences between the two groups on the secondary outcome measures, use of lo razepam or biperidin. CONCLUSION: Risperidone appears to be as effective as haloperidol in the tr eatment of cannabis-induced psychotic disorder.