Table 3.
Results of generalized estimating equations (GEEs) for the effects of bright light therapy on Beck Depression Inventory-Second Edition (BDI-II) scores and salivary cortisol levels.
| Variable | Regression Coefficient (95% CI) |
p |
|---|---|---|
| BDI-II Score | ||
| Group (BLT vs. control) | −3.02 (−7.46, 1.46) | 0.188 |
| Time | ||
| T1 vs. T0 | −1.27 (−4.14, 1.61) | 0.388 |
| T2 vs. T0 | −2.80 (−5.55, −0.05) | 0.046 |
| Interaction (group × time) | ||
| BLT × T1 vs. control × T0 | −7.57 (−11.63, −3.50) | <0.001 |
| BLT × T2 vs. control × T0 | −6.20 (−10.09, −2.31) | 0.002 |
| Salivary cortisol level | ||
| Group (BLT vs. control) | 3.02 (−4.47, 10.50) | 0.430 |
| Time | ||
| T1 vs. T0 | 2.65 (−1.02, 6.32) | 0.157 |
| T2 vs. T0 | 4.08 (−2.56, 10.72) | 0.259 |
| Interaction (group × time) | ||
| BLT × T1 vs. control × T0 | −7.37 (−12.56, −2.18) | 0.017 |
| BLT × T2 vs. control × T0 | −12.22 (−22.24, −2.20) | 0.005 |
BDI-II: Beck Depression Inventory-Second Edition (BDI-II); BLT: bright light therapy; CI: confidence interval; T0: baseline; T1: 3 weeks; T2: 6 weeks.