Tolerability of outpatient antipsychotic treatment: 36-month results from the European Schizophrenia Outpatient Health Outcomes (SOHO) study

SOHO is a 3-year, prospective, observational study of schizophrenia patients who started a new antipsychotic in 10 European countries. Cohorts of patients were defined according to the antipsychotic started at baseline: olanzapine, risperidone, quetiapine, amisulpride, clozapine, oral typical and depot typical antipsychotics. Tolerability in terms of rates of extrapyramidal symptoms (EPS), tardive dyskinesia (TD), anticholinergic use, loss of libido/impotence, amenorrhoea/galactorrhoea/gynaecomastia, and weight change was assessed in 4939 patients who started monotherapy. Logistic regression models related medication initiated at study entry to adverse events over follow-up, adjusting by baseline differences among treatment cohorts. Patients taking typical antipsychotics or risperidone were more likely to experience EPS and TD during follow-up than patients taking olanzapine. Patients taking olanzapine were less likely to have loss of libido/impotence during follow-up than patients in the risperidone, amisulpride, clozapine, oral typical and depot typical cohorts. Weight gain occurred in all groups, but was greater with olanzapine. In conclusion, antipsychotics have different tolerability profiles in terms of the adverse events we monitored. Results should be interpreted conservatively due to the observational study design.