Table 2 Reliability of PHQ-9
PHQ-9 Items | PHQ-9 Questions | Scale Mean if Item Deleted | Corrected Item-Total Correlation | Cronbach’s Alpha if Item Deleted | Items Mean ± SD |
|---|---|---|---|---|---|
PHQ-1 | Little interest or fun in doing things | 7.80 | 0.540 | 0.773 | 0.90 ± 1.08 |
PHQ-2 | Feeling down, depressed or hopeless | 7.34 | 0.602 | 0.764 | 1.36 ± 1.17 |
PHQ-3 | Trouble falling asleep, staying asleep or sleeping too much | 7.44 | 0.484 | 0.781 | 1.26 ± 1.23 |
PHQ-4 | Feeling tired or having little energy | 7.62 | 0.456 | 0.784 | 1.08 ± 1.15 |
PHQ-5 | Poor appetite or overeating | 7.66 | 0.494 | 0.779 | 1.04 ± 1.19 |
PHQ-6 | Feeling bad about yourself, or that you’re a failure or have let yourself or your family down | 7.57 | 0.456 | 0.784 | 1.13 ± 1.15 |
PHQ-7 | Trouble concentrating on things such as reading the newspaper or watching television | 7.68 | 0.522 | 0.775 | 1.02 ± 1.11 |
PHQ-8 | Moving or speaking so slowly that other people could have noticed. Or the opposite | 8.15 | 0.404 | 0.790 | 0.55 ± 0.97 |
PHQ-9 | Thoughts that you would be better off dead or hurting yourself in some way | 8.33 | 0.466 | 0.784 | 0.37 ± 0.82 |
Overall | Cronbach’s Alpha | 0.799 | 8.65 ± 6.1 | ||