Abstract
Purpose: To evaluate the rate and determinants of non-adherence to an-tipsychotic medications in Saudi Arabia. Ma-terials and methods: This was a cross-sec-tional study that included a questionnaire, interview, and data extraction from medical records of adult patients on antipsychotic medications. The study was conducted at outpatient clinics at the psychological care department at King Fahad Medical City, Ri-yadh, Saudi Arabia, between October 25 and November 26, 2020. Data collection includ-ed three parts: patients' sociodemographic characteristics; antipsychotic medications used and patients' clinical characteristics; and adherence to antipsychotic medica-tions measured by the Medication Adher-ence Rating Scale (MARS). Results: Out of 220 patients, 122 (55.5%) were considered non-adherent (MARS scores 6 or less). The MARS items contributing most to non -ad-herence were "the medication makes me feel tired and sluggish" and "forget to take the medication", 55 and 40.9%, respectively. Additionally, adverse drug effect signifi-cantly increased the risk of poor adherence in regression analysis (odds ratio = 1.97, p = 0.028). The model also showed that fe-male sex, low income, cigarette smoking, substance abuse, uncontrolled disease, co -morbidity, and use of Ruqyah religious ther-apy were associated with increased risk of poor adherence, but were however not sta-tistically significant (p < 0.05). Conclusion: This study showed high non-adherence rate to antipsychotic medications. Adverse drug effects and forgetting to take medications were the main patient-reported barriers to adherence. Likewise, sociodemographic, clinical, and spiritual factors affected medi-cation adherence. Knowing these predictors helps in early identification of patients who are predisposed to medication non -adher-ence and allows personalized interventions that improve adherence and treatment out-comes.