Table 2.
Single-Group Confirmatory Factor Analysis Models and Fit Indices Evaluating Factor Structure of the Patient Health Questionnaire-9 (PHQ-9) in U.S. Adults
| Model 1 | Model 2 | Model 3 | Model 4 | Model 5 | |
|---|---|---|---|---|---|
| 1. Anhedonia | Depression | Cognitive/Affective | Cognitive/Affective | Cognitive/Affective | Cognitive/Affective |
| 2. Depressed Mood | Depression | Cognitive/Affective | Cognitive/Affective | Cognitive/Affective | Cognitive/Affective |
| 3. Sleep Disturbance | Depression | Somatic | Somatic | Somatic | Somatic |
| 4. Fatigue | Depression | Somatic | Somatic | Somatic | Somatic |
| 5. Appetite Changes | Depression | Somatic | Somatic | Somatic | Somatic |
| 6. Low Self-Esteem | Depression | Cognitive/Affective | Cognitive/Affective | Cognitive/Affective | Cognitive/Affective |
| 7. Concentration Difficulties | Depression | Cognitive/Affective | Cognitive/Affective | Somatic | Cognitive/Affective |
| 8. Psychomotor Disturbances | Depression | Cognitive/Affective | Somatic | Somatic | Both |
| 9. Suicidal Ideation | Depression | Cognitive/Affective | Cognitive/Affective | Cognitive/Affective | Cognitive/Affective |
| Chi-Square (χ2) | 1783.11 | 941.82 | 1182.37 | 994.99 | 910.98 |
| Degrees of Freedom | 27 | 26 | 26 | 26 | 25 |
| p-value | <0.001 | <0.001 | <0.001 | <0.001 | <0.001 |
| RMSEA | 0.046 | 0.034 | 0.038 | 0.034 | 0.034 |
| RMSEA 90% Confidence Interval | 0.044 – 0.047 | 0.032–0.035 | 0.036–0.040 | 0.033–0.036 | 0.032–0.036 |
| TLI | 0.972 | 0.985 | 0.981 | 0.984 | 0.985 |
| CFI | 0.979 | 0.989 | 0.986 | 0.988 | 0.989 |
Note. N = 31,366. For absolute fit indices (RMSEA), exact fit = 0.00, close fit = 0.01–0.05, acceptable fit = 0.05–0.08, mediocre fit = 0.08–0.10, and poor fit = greater than 0.10. For relative fit indices (TLI and CFI), exact fit = 1.00, close fit = 0.95–0.99, acceptable fit = 0.90–0.95, mediocre fit = 0.85–0.90, and poor fit = less than 0.85. RMSEA = root mean square error of approximation. TLI = Tucker-Lewis index. CFI = comparative fit index