Interpreting the efficacy findings in the CATIE study: what clinicians should know

The Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) schizophrenia trial was an effectiveness/"pragmatic" clinical trial designed to compare the efficacy, tolerability, and cost-effectiveness of four atypical antipsychotics (olanzapine, quetiapine, risperidone and ziprasidone) and a conventional antipsychotic (perphenazine) for an 18-month period in patients with schizophrenia. The study randomized 1,460 patients with fewer exclusion criteria than in most trials in hopes that this would allow for a more representative sample of outpatients in "real world" practice. Olanzapine demonstrated significant superiority in time to discontinuation for all cause and for lack of efficacy, as well as likelihood of hospitalization for relapse; however, it was associated with a significantly higher rate of metabolic side effects. Perphenazine exhibited comparable effectiveness with quetiapine, risperidone, and ziprasidone, and appeared to be as well tolerated as the atypicals. However, it had the highest rate of drop out due to extrapyramidal symptoms and was restricted to patients who did not have tardive dyskinesia (TD). This article examines the phase 1 CATIE results to guide the clinician in understanding how to interpret the findings, which were intended to be a guide for clinical practice. The nature of the patient population, the doses of drugs relative to one another, inclusion of patients who were treatment resistant, and exclusion of patients with TD from randomization to perphenazine were potential sources of bias in the study. In particular, the use of a higher-than-usual peak dose of olanzapine may have led to the superior results achieved with it. Practical suggestions are given for choice of antipsychotic medication in patients with chronic schizophrenia.