Prevalence and risk factors for extrapyramidal syndromes (EPS) were investigated in a sample of 1,559 patients.The overall prevalence of EPS was 29.4% (N = 458). Among the EPS-diagnosed patients, parkinsonism as assessed by the presence of core parkinsonian symptoms (rigidity, tremor, bradykinesia) was present in 65.9% of patients (N = 302), akathisia in 31.8% (N = 145), and acute dystonia in 2.1% (N = 10).
Old age and long-term neuroleptic drug (NL) treatment were significantly associated with EPS in both the univariate and the multivariate analyses, whereas no relationship was observed with average NL daily doses and current NL treatment. EPS was diagnosed in 50.2% of 285 patients with persistent tardive dyskinesia (TD). Distribution of EPS in patients with TD showed that tremor and akathisia were more frequent in peripheral TD cases than in orofacial TD cases. Furthermore, there was a stronger association of NL-induced parkinsonism with peripheral TD than with orofacial TD. This study suggests that the association between EPS and TD may be limited to specific subtypes of TD. Peripheral TD showed a higher association with parkinsonism and with akathisia, suggesting that these symptoms may share a common pathophysiology. (J Clin Psychopharmacol 1999;19:203-208)