The relationship of extrapyramidal symptoms and schizophrenia psychopathology

Findings are reported from 41 DSM-III-R diagnosed "treatment-refractory" patients with schizophrenia, randomized to 100,300 and 600 mg of double-blind doses of clozapine for 16 weeks. Extrapyramidal (EPS) scores were computed using gait, rigidity and tremor from Simpson Angus Rating Scale. Using BriefPsychiatric Rating Scale (BPRS) fivefactors were derived: Anergia (AN), Thought Disturbance (THOT), Activation (AC), Hostility-Suspiciousness (HS) and Anxiety-Depression (AD). The associations between EPS and BPRS factors, analyzed using Pearson's correlations, showed that in the whole group (n=41), EPS had positivecorrelations with AN, THOT, AC and negative correlations with HS and AD. Repeating the analysis in 20 subjects 'with' EPS (total EPS scorea S), the level of association improved significantlywith Anergia, while it remained inconsistent with the other factors. To assess the influence of the severity of EPS on BPRS factors, repeated measures MANOVA in subjects 'with' EPS divided into 'high' and 'low' EPS-subgroups (median split>6) showed significant group differences in Anergia factor, while it was reversed for HS and AD. THOT and AC failed to show group differences. Our observation of a significant association between EPS and Anergia and an inverse relationship of EPS to HS and AD may contribute to understanding pathophysiological mechanisms.