Factors associated with high‐dose antipsychotic prescriptions in outpatients with schizophrenia: An analysis of claims data from a Japanese prefecture

BACKGROUND: Antipsychotics are commonly prescribed in high doses in combination with multiple psychotropic drugs. This study focused on the high‐dose antipsychotic prescriptions in patients with schizophrenia, while aiming to identify their associations with patients’ characteristics and concurrent psychotropic prescriptions. METHODS: This cross‐sectional study used claims data from a prefecture in Japan, between October 2014 and March 2015, to investigate antipsychotic prescriptions in adult outpatients with schizophrenia. The objective variable was the presence/absence of a high‐dose prescription. The explanatory variables included sex, age (category), presence of comorbid conditions, and the use of psychiatrist's therapy. RESULTS: After exclusion, a total of 13 471 patients with schizophrenia were analyzed. The frequency of high‐dose prescriptions was higher in men, with chlorpromazine‐equivalent values highest in the age ranges of 45‐54 and 35‐44 years for men and women, respectively. Patients aged below 65 years with cerebrovascular diseases showed a decrease in high‐dose prescriptions. There was a high frequency of polypharmacy psychotropic drug use in combination with a high‐dose antipsychotic prescription in patients aged below 65 years. CONCLUSION: High‐dose antipsychotics are often used in combination with several psychotropic agents in patients with schizophrenia. Our findings emphasize the need to evaluate the prescribing behavior of physicians to avoid high‐dose antipsychotic prescriptions for improved patient care.