Psychotropic Drug Prescription Patterns and Their Predictors among Older Adult Patients with Schizophrenia in a Tertiary-referral Psychiatric Hospital

Objective: Medical treatments for patients with refractory schizophrenia can be roughly divided into three strategies - clozapine administration, adjuvant use of mood stabilizers, and antipsychotic polypharmacy. Few studies exist on older adult patients with schizophrenia. In this study, we intended to assess the prevalence of clozapine administration, adjuvant use of mood stabilizers, and antipsychotic polypharmacy, and to find their predictors in those patients with schizophrenia. Methods: In this cross-sectional study, we collected information of patients' sociodemographic and clinical details. Their psychotic symptoms were evaluated using a clinical interview with a positive and negative syndrome scale (PANSS). Results: We enrolled 240 study participants, with 74 patients (30.8%) receiving clozapine, 40 patients (16.7%) receiving adjuvant use of mood stabilizers, and 42 patients (17.5%) receiving antipsychotic polypharmacy. Younger age (p ＜ 0.05), higher PANSS general symptoms subscales (p ＜ 0.001), and higher dosage of antipsychotics (p ＜ 0.01) were significantly related to patients with clozapine administration. As to patients with adjuvant therapy with mood stabilizers, only younger age (p ＜ 0.01) and male gender (p ＜ 0.05) showed significant association. Finally, patients receiving antipsychotic polypharmacy were significantly related to lower body mass index (BMI) (p ＜ 0.05), higher PANSS positive symptoms subscale (p ＜ 0.05), and higher dosage of antipsychotics (p ＜ 0.001). Conclusions: Our findings showed that patients with clozapine prescription were 30.8% in prevalence which is higher than other studies in Asia. The prevalence of adjuvant mood stabilizers and antipsychotic polypharmacy were 16.7% and 17.5%, respectively. Those two findings are lower than those in other studies in Asia.