Time to study discontinuation, relapse, and compliance with atypical or conventional antipsychotics in schizophrenia and related disorders

To more clearly clarify the efficacy of the atypical antipsychotics compared to conventional antipsychotics, we add data on the outcome of patients diagnosed with schizophrenia from two large, international clinical trials comparing olanzapine with haloperidol (n = 1996) and olanzapine with risperidone (n = 339). Both studies comprised double-blinded, placebo controlled, random assignment trials. Health outcomes reported include: (i) time to discontinuation in the trial; (ii) clinical relapse; and (iii) time to drug non-compliance. When outcome was measured as time to discontinuation due to adverse events or lack of efficacy, olanzapine showed superiority over haloperidol and no difference compared to risperidone. Of those patients who had an initial response, there was no significant difference between olanzapine and haloperidol when outcome was measured using either: (i) 52-week relapse rates or (ii) time to first non-compliance. Using the measures of study discontinuation, relapse and non-compliance, in one trial the atypical antipsychotic olanzapine was superior to haloperidol, while in a second trial there were no differences between olanzapine and risperidone.