Validity and reliability of the Persian version of the mental health quality of life questionnaire (MHQoL) in patients with major depressive disorder in Iran

The Mental Health Quality of Life (MHQoL) questionnaire is an extremely short instrument created to evaluate quality of life domains relevant to mental health. Given the substantial impairment in quality of life among patients with major depressive disorder (MDD), evaluating the psychometric properties of the MHQoL in this population is essential for both clinical practice and research. The study was conducted between 2023 and 2024 in psychiatric outpatient clinics in Iran. A total of 141 patients clinically diagnosed with MDD were recruited using convenience sampling during routine psychiatric visits. Internal consistency was tested using Cronbach's alpha and composite reliability. Construct validity was tested using a confirmatory factor analysis and Average Variance Extracted (AVE). Convergent validity was tested by correlations with the Functional Assessment of Chronic Illness Therapy–Spiritual Well-Being Scale (FACIT-Sp-12), divergent validity through correlations with the General Health Questionnaire (GHQ-12), and discriminant validity by the Fornell–Larcker criterion. Known-group validity was examined by comparison of patients with illness duration ≤ 5 years versus > 5 years. Test–retest reliability was assessed over a two-week interval in a subsample. The Persian MHQoL had acceptable internal consistency (Cronbach’s α = 0.72) and good composite reliability (ρa = 0.91; ρc = 0.87). Indeed, with AVE values higher than the recommended 0.50 and significant factor loadings all above 0.50, convergent validity was demonstrated. MHQoL scores were positively correlated with FACIT-Sp dimensions (r = 0.42–0.69, p < 0.001) and negatively correlated with GHQ scores, with the strongest negative association for future outlook (r = − 0.72) and mood (r = − 0.68). Fornell–Larcker criteria confirmed discriminant validity. Known-group comparisons indicated significant differences in self-image and physical health considered by illness duration (p < 0.01); paradoxically, patients with longer illness duration scored higher on these domains, possibly mirroring adaptation or treatment effects. A high test–retest reliability was evidenced (ICC = 0.83–0.86). The Persian MHQoL is a culturally adapted, psychometrically robust tool for measuring mental health-related quality of life in individuals with MDD. Due to its brevity, reliability, and validity, it is applicable in both clinical and research settings involving Persian-speakers.