Risperidone versus olanzapine for schizophrenia

We found no difference for the outcome of unchanged or worse in the short term (n=548, 2 RCTs, RR 1.00 CI 0.88 to 1.15). One study favoured olanzapine for the outcome of relapse/rehospitalisation by 12 months (n=279, 1 RCT, RR 2.16 CI 1.31 to 3.54, NNH 7 CI 3 to 25). Most mental state data showed the two drugs to be as effective as each other (n=552, 2 RCTs, RR 'no <20% decrease PANSS by eight weeks' 1.01 CI 0.87 to 1.16). Both drugs commonly cause adverse events: 75% given either drug experience an adverse event; 20% anticholinergic symptoms; both groups experienced insomnia although it was more frequent with risperidone (n=1588, 5 RCTs, RR 1.41 CI 1.15 to 1.72, NNH 15 CI 9 to 41); about 30% experienced sleepiness (n=1713, 6 RCTs, RR 0.92 CI 0.79 to 1.07). People given either drug often experienced some extrapyramidal symptoms (n=893, 3 RCTs, RR 1.18 CI 0.75 to 1.88); 25% of people using risperidone required medication to alleviate these symptoms (n=419, 2 RCTs, RR 1.76 CI 1.25 to 2.48, NNH 8 CI 4 to 25). People allocated to risperidone were less likely to gain weight compared with those given olanzapine and the weight gain was often considerable and of quick onset (n=984, 2 RCTs, RR gain more than 7% of their baseline weight in short term 0.47 CI 0.36 to 0.61, NNH 7 CI 6 to 10). Risperidone participants were less likely to leave the study due to metabolic side effects and weight gain compared with olanzapine (n=667, 1RCT, RR 0.19 CI 0.08 to 0.45). Patients on risperidone were more likely to experience abnormal ejaculation (n=370, 2 RCTs, RR 4.36 CI 1.38 to 13.76, NNH 20 CI 6 to 176). Both drugs are associated with high attrition rates; in the long term consistent findings show that 66% of those allocated risperidone left the study early compared with 56% given olanzapine (n=1440, 5 RCTs, RR 1.17 CI 1.08 to 1.27, NNH 11 CI 7 to 23).