Medication adherence and associated factors among psychiatric patients in Mozambique: longitudinal analyses of data from 2022–2024

Background: Mental disorders are a major contributor to global disability and mortality, with medication nonadherence presenting a significant barrier to effective treatment. Research on adherence among psychiatric patients is particularly sparse in low- and middle-income countries (LMICs). This study examined the relationship between psychiatric medication adherence and clinical and sociodemographic factors in outpatient psychiatric settings in central Mozambique. Methods: We conducted a longitudinal study using data from 803 outpatient psychiatric patients (1,811 total follow-up visits) attending eight healthcare facilities in Mozambique from February 2022 to January 2024. The primary exposure variables in this study include primary diagnoses (epilepsy, schizophrenia-related disorders, other psychotic and delusional disorders, depression-related disorders, mental and behavioral disorders due to substance use, and all other diagnoses). “All other diagnoses” grouped together any ICD-10 code psychiatric diagnoses with fewer than 15 patients each. Primary medications (Carbamazepine, Haloperidol, Amitriptyline, Thioridazine, and all other medications). “All other medications,” grouped together those medications with fewer than 15 patients each. Sociodemographic characteristics include age (<18, 18-35, 36-55, and over 56 years), gender (female and male), and marital status (single, married, divorced, separated, widowed, and common-law). Patient adherence was determined by a combination of pill counts and patients self-declaring they took their medication as prescribed. We analyzed medication adherence and its association with sociodemographic and clinical variables using non-parametric Kaplan-Meier and semi-parametric Cox proportional hazards models. A multivariate linear mixed model was employed to analyze the association between psychiatric medication and clinical/sociodemographic variables and changes in weight, the World Health Organization Disability Assessment Schedule (WHODAS), and blood pressure over time. Results: Approximately 93% of patients (N = 729) were non-adherent to their medication at least at one follow-up visits during the study period, with a median time in treatment prior to non-adherence of 60 days (mean: 52 days; 95% CI: 51, 53). In fully-adjusted models, patients aged 56+ had a 31% higher hazard of nonadherence compared to those aged 18–35 (aHR: 1.31; 95% CI: 1.10, 1.57). Patients prescribed amitriptyline had a 54% higher hazard of nonadherence compared to those prescribed carbamazepine (aHR: 1.54; 95% CI: 1.19, 1.99). For each 30 days in treatment, disability scores decreased by an average of 0.13 (95% CI: -0.16 to -0.09), while systolic blood pressure decreased by 0.46 mmHg (95% CI: -0.18 to -0.10), and diastolic blood pressure decreased by 0.15 mmHg (95% CI: -0.23 to -0.06). Patients diagnosed with schizophrenia-related disorders and those in the ‘all other diagnoses’ group had higher disability scores (aβ = 2.0; 95% CI: 0.88, 3.17, and aβ = 1.8; 95% CI: 0.69, 2.91, respectively), compared to patients with epilepsy. Male patients on treatment had a marginally lower diastolic blood pressure (aβ=-4.39 mmHg; 95% CI: -8.51, -0.27) compared to females. Patients in the ‘all other medication’ group had a weight 3.21 kg lower (95% CI: -6.41, 0.01) compared to those taking carbamazepine. Conclusions: Currently, the typical patient who initiates essential psychiatric treatment in Mozambique is only able to maintain adherence to their medication for 60 days. Patients prescribed amitriptyline and older patients are at a higher risk of non-adherence. Consistent engagement in treatment is linked to lower disability scores and blood pressure. There is an urgent need for research into adherence support strategies, especially for these high-risk groups within Mozambique’s mental health patient population.