Assessment of the latent adverse events of antipsychotic treatment using a subjective questionnaire in Japanese patients with schizophrenia

Objective: The adverse effects of antipsychotic agents can have a marked influence on medication adherence. In this study, we investigated the adverse events of antipsychotics that are less likely to be reported by patients and the reasons why such symptoms remain latent. Methods: Data were collected by interviewing patients using a subjective questionnaire, and the associations between unreported symptoms and background factors were investigated. Results: A total of 306 patients with schizophrenia or schizoaffective disorder were examined. Their major symptoms were daytime sleepiness (50.0%), weight gain (42.2%), and sexual dysfunction (38.9%). Sexual dysfunction was nominal significantly more common among the patients that had been treated with antipsychotic agent polypharmacy (odds ratio [OR], 2.14; 95% confidence interval [CI], 1.07 to 4.30), and was nominal significantly more common among outpatients (OR, 1.78; 95% CI, 1.02 to 3.13). Only approximately 30% of the patients had reported their symptoms to their physicians. Conclusion: Patients receiving antipsychotic treatment tolerate some symptoms and do not feel able to report them to their physicians. The most common reason for this is an insufficient patient-physician relationship. Sexual dysfunction is especially hard to identify because it is a delicate problem, and our findings demonstrate that subjective questionnaires are helpful for detecting such symptoms.