ABSTRACT
Background: Among the common mental disorders in societies, depression is one of the most common mental disorders that affects all groups and classes of society. Students are among the groups with the highest rates of depression. Therefore, the need for a short and effective tool for screening and early detection of depression is felt. The aim of this research is to determine validity, reliability and the best cut-off point of the patient health questionnaires-9 (PHQ-9) and patient health questionnaires-2 (PHQ-2) in university students. Methods: This cross-sectional study was conducted on 246 students of Kermanshah University of medical science in Kermanshah province of Iran. They completed the PHQ-2, PHQ-9, and the Beck Depression Inventory-II (BDI-II). A structured interview was used to diagnose depression. To analyze the data, Cronbach's alpha for internal consistency, the intra-class correlation (ICC) for test-retest reliability, confirmatory factor analysis for construct validity, Pearson Correlation for Convergent validity, and receiver-operating characteristic (ROC) curve for Criterion validity was used. Results: The mean age of the participants was 20.43 ± 2.29. Cronbach's alpha coefficient for PHQ-9 and PHQ-2 was 0.82 and 0.80, respectively. The test-retest reliability based on intra-class correlation (ICC) for PHQ-9 and PHQ-2 after two weeks was 0.81 and 0.73, respectively (P < 0.001). The correlation coefficient between the PHQ-9 and PHQ-2 with the BDI-II was 0.74 and 0.64, respectively (P < 0.001). Confirmatory factor analysis showed that two-factor model and one factor model had good model fit. The best cut-off point score for the PHQ-9 was 10 with a sensitivity of 0.90 and specificity of 0.93, and the best cut-off point score for the PHQ-2 was 3 with the sensitivity of 0.71 and specificity of 0.92. Conclusions: The PHQ-9 and PHQ-2 are suitable tools to screen depression in the university students in Iran.
