Table 2.
Sensitivity, specificity, and positive and negative predictive values for a diagnosis MDD across various cutoffs of the PHQ-9 (n = 101)
| Cutoff Score | Sensitivity (%) | Specificity (%) | Positive Predictive Value (%) | Negative Predictive Value (%) | Youden’s Index |
|---|---|---|---|---|---|
| Self-rated | |||||
| 3 | 100.0 | 19.5 | 22.4 | 100.0 | 0.195 |
| 4 | 100.0 | 25.6 | 23.8 | 100.0 | 0.256 |
| 5 | 100.0 | 35.4 | 26.4 | 100.0 | 0.354 |
| 6 | 89.5 | 37.8 | 25.0 | 93.9 | 0.273 |
| 7 | 78.9 | 43.9 | 24.6 | 90.0 | 0.229 |
| 8 | 78.9 | 50.0 | 26.8 | 91.1 | 0.289 |
| 9 | 73.7 | 56.1 | 28.0 | 90.2 | 0.298 |
| 10 | 68.4 | 58.5 | 27.7 | 88.9 | 0.270 |
| 11 | 63.2 | 63.4 | 28.6 | 88.1 | 0.266 |
| 12 | 63.2 | 70.7 | 33.3 | 89.2 | 0.339 |
| 13 | 57.9 | 75.6 | 35.5 | 88.6 | 0.335 |
| 14 | 47.4 | 79.3 | 34.6 | 86.7 | 0.266 |
| 15 | 36.8 | 85.4 | 36.8 | 85.4 | 0.222 |
| Parent-rated | |||||
| 3 | 78.9 | 34.1 | 21.7 | 87.5 | 0.131 |
| 4 | 78.9 | 40.2 | 23.4 | 89.2 | 0.192 |
| 5 | 73.7 | 50.0 | 25.5 | 89.1 | 0.237 |
| 6 | 73.7 | 58.5 | 29.2 | 90.6 | 0.322 |
| 7 | 57.9 | 64.6 | 27.5 | 86.9 | 0.225 |
| 8 | 47.4 | 73.2 | 29.0 | 85.7 | 0.205 |
| 9 | 47.4 | 75.6 | 31.0 | 86.1 | 0.230 |
| 10 | 42.1 | 78.0 | 30.8 | 85.3 | 0.202 |
| 11 | 36.8 | 80.5 | 30.4 | 84.6 | 0.173 |
| 12 | 31.6 | 84.1 | 31.6 | 84.1 | 0.157 |
Grey: the proposed cutoff. Orange: the statistically optimal cutoff based on the Youden’s Index. Data contributed by author