Reasons and Outcomes of Olanzapine Dose Adjustments in the Outpatient Treatment of Schizophrenia

Abstract

Antipsychotic treatment dose adjustments may influence treatment outcomes in patients with schizophrenia. We analysed data from 4,247 outpatients with schizophrenia who started olanzapine monotherapy in the 3-year, prospective, observational SOHO study to determine factors associated with olanzapine dose adjustments and how these impact on treatment effectiveness and tolerability. Regression analyses showed an association between changes in the Clinical Global Impression (CGI) and olanzapine dose changes: patients with a lack of effectiveness were more likely to have their dose increased, whereas patients with good treatment response were more likely to have a dose decrease. Improvement in tardive dyskinesia was associated with dose increase or no change (p=0.034) and worsening of sexual problems was associated with dose decrease (p=0.001). Conversely, an increase in olanzapine dose was associated with subsequent clinical improvement (CGI), but dose adjustment had no significant effects on tolerability outcomes. These results indicate that psychiatrists tend to modify olanzapine dose according to treatment response. Dose increases seem to be associated with a better response to treatment and not with a worsening of side-effects.