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

INTRODUCTION: Few controlled data exist on the treatment of substancehaloperidol induced psychotic disorders. Our aim was to investigate the effects of risperidone and haloperidol. METHOD: 30 patients who met DSM-IV criteria for cannabis-induced psychotic disorder were randomly allocated to receive either risperidone or haloperidol in a 4-week randomized controlled double-blind clinical trial. RESULTS: There were no significant outcome differences between the two groups on any of the primary outcome measures, the Brief Psychiatric Rating Scale, Clinical Global Impression scale or the Global Assessment of Functioning Scale. No extrapyramidal side-effects (EPS), as measured by either the Simpson Angus Scale or the Barnes Akathisia Scale, emerged in the risperidone group; this was however not statistically different to the haloperidol group due to the low rate of EPS in that group. There were no significant differences between the two groups on the secondary outcome measures, use of lorazepam or biperidin. CONCLUSION: Risperidone appears to be as effective as haloperidol in the treatment of cannabis-induced psychotic disorder. (Int J Psych Clin Pract 2000; 4:139-142).