The psychosis of schizophrenia: prevalence, response to atypical antipsychotics, and prediction of outcome

BACKGROUND Psychosis is a defining feature of schizophrenia consisting of formal thought disorder, delusions, and hallucinations. Although psychosis is present in the majority of patients with schizophrenia, the prevalence, responsiveness to atypical antipsychotic drug therapy, and prediction of outcome of individual psychotic symptoms in a population of well-diagnosed patients with schizophrenia have not been conclusively established. METHODS This paper examined the prevalence, responsiveness to the atypical antipsychotic olanzapine, and relationship to outcome of individual psychotic symptoms using data from a previously reported large multicenter, double-blind clinical trial of olanzapine (mean daily dose at endpoint = 13.6 +/- 6.9 mg/day). RESULTS The most frequently reported psychotic symptoms at baseline were delusions (65%), conceptual disorganization (50%), and hallucinations (52%), and the majority of patients (68%) experienced from one to three symptoms. Additionally, with olanzapine treatment there were significant improvements (p < .001) in baseline to endpoint Positive and Negative Symptom Scale (PANSS) psychotic item scores, with the largest effect sizes observed for hallucinatory behavior, unusual thought content, suspiciousness/persecution, and delusions. During the acute phase of the trial, quality of life was correlated significantly with baseline conceptual disorganization (p = .038) and unusual thought content (p = .023), and time spent in the hospital was correlated with unusual thought content (p = .005). CONCLUSIONS The implications of these for the clinical management of schizophrenia are discussed.