Validity and Reliability of the Persian PHQ-9 in Community-Dwelling Adults

IntroductionDepression is one of the most common mental disorders worldwide and in Iran. Although the PHQ-9 has been translated into Persian, the previous Iranian validation was conducted in psychiatric outpatients with a relatively small sample and did not fully examine its performance in the general population. Therefore, further evaluation of the Persian PHQ-9 in a community sample was needed.MethodThis cross-sectional study used a convenience sampling method to employ 1169 participants from public locations in Gonabad, Iran, between 2024 and 2025. Eligible participants were adult residents (aged 18 years or older) who could complete the questionnaires in Persian. After completing the questionnaires in a self-report manner, Cronbach's alpha, McDonald's omega, and Intraclass Correlation Coefficient (ICC) indices were calculated to assess reliability. Also, to assessed the construct validity, confirmatory factor analysis (CFA) and exploratory factor analysis (EFA) was carried out.ResultsA total of 1,169 participants were included in the analysis. In the EFA subsample, the mean age was 37.66 ± 13.50 years, and in the CFA subsample, it was 36.26 ± 12.94 years. The one-factor model showed acceptable fit indices in CFA (CFI = 0.945, RMSEA = 0.078, AGFI = 0.924). Cronbach's alpha, McDonald's omega, and the ICC were 0.863, 0.869, and 0.932, respectively. The final model was unidimensional with one correlated residual. In reliability stage, Cronbach's alpha, McDonald's omega, and ICC for PHQ-9 were 0.863, 0.869 and 0.932 respectively.ConclusionThe results of this study confirm that the Persian PHQ-9 is an appropriate and brief instrument for assessing depression severity in the Iranian population.