Table 2.
Means, standard deviations, effect sizes, and summary statistics for the primary and secondary outcome measures comparing cases of persistent depression vs. cases of current major depression [intention to treat analysis (n = 30)].
| Pre-treatment | Post-treatment | Follow-up | Effect size for T0-T1 | Effect size for T0-T2 | Interaction effect (time × group) |
Main effect F (time) |
Main effect F (group) |
||
|---|---|---|---|---|---|---|---|---|---|
| HamD | PDD | 20.7 ± 5.7 | 5.1 ± 4.1 | 4.2 ± 3.9 | −3.1 | −3.4 | F(1.1, 32) = 0.3, p = 0.62 | F(1.1, 32) = 127.6, p < 0.01 | F(1, 28) = 1.2, p = 0.28 |
| MDD | 21.2 ± 4.6 | 7.3 ± 5.7 | 5.9 ± 6 | −2.7 | −2.9 | ||||
| BAI | PDD | 16.5 ± 11.6 | 9.5 ± 7.6 | 5.3 ± 3.8 | −0.7 | −1.3 | F(1.4, 38.9) = 0.8, p = 0.41 | F(1.4, 38.9) = 14.9, p < 0.01 | F(1, 28) = 1.1, p = 0.31 |
| MDD | 18.9 ± 13.3 | 10.4 ± 9 | 10.8 ± 10.2 | −0.7 | −0.7 | ||||
| PBRS | PDD | 20.6 ± 6.1 | 15.4 ± 7 | 12.4 ± 3.6 | −0.8 | −1.6 | F(2, 56) = 1.9, p = 0.17 | F(2, 56) = 18.4, p < 0.01 | F(1, 28) = 0.9, p = 0.34 |
| MDD | 22 ± 4.9 | 14.7 ± 5.3 | 16.5 ± 7.6 | −1.4 | −0.8 | ||||
| NBRS | PDD | 28.8 ± 6.7 | 23.4 ± 7.3 | 18.9 ± 5.1 | −0.8 | −1.7 | F(1.6, 44.8) = 2.6, p = 0.1 | F(1.6, 44.8) = 32.2, p < 0.01 | F(1, 28) = 0.1, p = 0.94 |
| MDD | 28.3 ± 6.9 | 21.5 ± 5.1 | 21.7 ± 4.8 | −1.1 | −1.1 | ||||
| MCQ-30 | PDD | 62 ± 13 | 51.9 ± 13.8 | 44.8 ± 11.7 | −0.8 | −1.4 | F(1.5, 42.3) = 1.1, p = 0.34 | F(1.5, 42.3) = 27.6, p < 0.01 | F(1, 28) = 1.6, p = 0.22 |
| MDD | 67.5 ± 13.9 | 53.1 ± 12.1 | 52.5 ± 11.5 | −1.1 | −1.2 | ||||
| RRS | PDD | 50.7 ± 10.7 | 38.3 ± 11.5 | 32.2 ± 8.3 | −1.1 | −1.9 | F(1.4, 37.9) = 1.4, p = 0.26 | F(1.4, 37.9) = 33.2, p < 0.01 | F(1, 28) = 1.6, p = 0.22 |
| MDD | 53.3 ± 9.9 | 38.6 ± 9.5 | 39.5 ± 10.2 | −1.5 | −1.4 |
MDD, Current major depressive disorder; PDD, Persistent depressive disorder; HamD, Hamilton depression scale; BAI, Beck anxiety inventory; PBRS, Positive beliefs about rumination scale; NBRS, Negative beliefs about rumination scale; MCQ-30, Metacognition questionnaire; RRS, Ruminative response scale; d = 0.2–0.4: small effect; d = 0.5–0.7: medium effect; d ≥ 0.8: large effect.