Effectiveness and efficacy: Staying on treatment and symptom reduction

The goal of CATIE was to conduct a comparison of the effectiveness of the newer (atypical or second-generation) antipsychotic medications, each relative to the others, as well as to an older (conventional or first-generation) antipsychotic comparator. Efficacy studies had already demonstrated that all of these agents produced a therapeutic antipsychotic effect relative to placebo under optimal conditions. Our main goal was to determine their effectiveness relative to each other under “real-life” conditions. In this chapter, we present the rationale for the primary effectiveness outcome and results for the randomized phases of the study. In addition, we present analyses of comparative effects of the medications on symptoms in the initial phase of the study. The primary purpose of efficacy studies is to determine if a candidate antipsychotic compound has antipsychotic efficacy. The central question around which efficacy studies are constructed is, “Does this compound reduce the manifestations of psychosis?” The optimal patients to include in efficacy studies manifest potentially treatment-responsive psychosis. In order to have the best chance of demonstrating antipsychotic efficacy, if the compound can produce such an effect, the persons conducting efficacy trials (usually sponsored by pharmaceutical companies) recruit patients who are expected to be treatment responsive, for example, patients who failed to comply with prescribed antipsychotic medication and subsequently suffered a psychotic exacerbation. If treated with an efficacious antipsychotic compound such patients' psychotic features will diminish.