Incidence of Extrapyramidal Symptoms and Tardive Dyskinesia in Schizophrenia

The incidence of treatment-emergent extrapyramidal symptoms (EPSs) and tardive dyskinesia (TD) in schizophrenic patients, and the clinical characteristics associated with an increased risk of developing EPSs and TD were examined. Patients (N = 7728) in the 3-year, prospective, observational Schizophrenia Outpatient Health Outcomes study were examined according to baseline antipsychotic drug exposure. At baseline, 4893 patients (63.3%) had no EPS, and 6921 (89.6%) had no TD. Extrapyramidal symptoms and TD were assessed separately during follow-up: frequency and time to appearance from Kaplan-Meier survival curves and factors associated with time to appearance using Cox proportional hazard regression models. The cumulative incidence of EPS ranged from 7.7% (olanzapine) to 32.8% (depot typical drugs). Compared with olanzapine, patients taking depot typical drugs, oral typical drugs, risperidone, and amisulpride had a significantly higher risk of developing EPS. Differences from clozapine were marginally significant. High baseline clinical severity was associated with a significantly higher risk of developing EPS. The incidence of TD ranged from 2.8% (olanzapine) to 11.1% (depot typical agent). Compared with olanzapine, patients taking depot typical agents, oral typical agents, and risperidone had a significantly higher risk of developing TD. Baseline factors associated with a significantly higher risk of developing TD were age, EPS, a higher negative Clinical Global Impression score, and presence of gynecomastia. In summary, patients treated with typical antipsychotic agents (oral and depot) and risperidone had a higher risk of developing EPS and TD than patients treated with olanzapine. Higher baseline clinical severity was associated with EPS development, whereas age, presence of EPS, a higher negative Clinical Global Impression score, and presence of gynecomastia were associated with TD development.