Analysis of two depression questionnaires PHQ-9 and BDI-II
Abstract
The article examines two of the most commonly used depression questionnaires PHQ-9 and BDI-II. This study aimed to analyze results and psychometric properties of BDI-II and PHQ-9 among 392 students and stuff of various Novosibirsk universities. According to PHQ-9, 8 people belong to the group of severe depression, 38 people belong to the group of moderately severe depression. According to the questionnaire BDI-II, 20 people belong to the group of severe depression, 50 people belong to group of moderate severe depression. The results provide evidence of good and excellent reliability of PHQ-9 and BDI-II (Cronbach's alpha was 0,83 for PHQ-9 and 0,905 for BDI-II). Convergent validity was ρ = 0,71, p<0,001. The study confirmed one-factor structure of PHQ-9. The factor structure of BDI-II was not established, although the two-factor model represents the best fit to the data. Such a difference in the levels of depression and the lack of BDI-II factor structure in this study may be due to the fact that this questionnaire does not reflect the specific components of depression, but it`s reflect features of the student sample. The possibility of applying the BDI-II questionnaire to a non-clinical sample is discussed.
Keywords: depression, Beck depression inventory, BDI-II, Patient Health Questionnaire, PHQ-9.
