Factors associated with expression of extrapyramidal symptoms in users of atypical antipsychotics

The aim of this study was to investigate factors associated with the occurrence of extrapyramidal symptoms (EPS) in users of second-generation antipsychotics (SGA).

Observational cross-sectional study based on a random sample of subjects from three outpatient clinics. Inclusion criteria were age between 18 and 65 years, of both genders, with a diagnosis of schizophrenia and under the use of a single SGA agent. Subjects who had received i.m. long-acting antipsychotics in the past were excluded. The families of eligible patients were contacted by phone and, if willing to participate in the study, a household visit was scheduled. Informed consent was obtained from all study subjects and their next of kin. The risk of EPS associated with sociodemographic, clinical features and medications used was analyzed by logistic regression.

The study population consisted of 213 subjects. EPS were observed in 38.0% of subjects. The more commonly used SGA were olanzapine (76, 35.7%), risperidone (74, 34.3%), quetiapine (26, 12.2%), and ziprasidone (23, 10.8%). Among the drugs used as adjunctive therapy for schizophrenia, benzodiazepines were the most prevalent (31.5%), followed by carbamazepine (24.4%) and antidepressants (20.2%). Multivariate analysis showed that the risk of EPS was associated with the use of carbamazepine (odds ratio 3.677, 95% CI 1.627-8.310). We found no evidence that the type of SGA modified the risk of EPS.

The occurrence of EPS in SGA users is a common finding, with no difference of antipsychotics studied in relation to the risk of extrapyramidal manifestations. The adjunctive use of carbamazepine may predispose the user of SGA to the occurrence of EPS.