Table 5.
Psychiatric Comorbidity Moderating the Effect of Treatment Condition on Outcomes
| Interaction Coefficient | SE | p-value | 95% Confidence Interval | |
|---|---|---|---|---|
| ISI Severity | ||||
| CT vs. BT | −2.56 | 2.88 | 0.38 | −8.21, 3.10 |
| CBT vs. CT | 3.18 | 3.00 | 0.29 | −2.69, 9.05 |
| CBT vs. BT | 0.63 | 2.92 | 0.83 | −5.09, 6.34 |
| ISI Response | ||||
| CT vs. BT | 0.51 | 0.92 | 0.58 | −1.29, 2.30 |
| CBT vs. CT | −1.29 | 1.05 | 0.22 | −3.36, 0.77 |
| CBT vs. BT | −0.79 | 1.09 | 0.47 | −2.93, 1.36 |
| ISI Remission | ||||
| CT vs. BT | 1.73 | 0.99 | 0.08 | −0.21, 3.67 |
| CBT vs. CT | −1.93 | 1.04 | 0.06 | −3.96, 0.10 |
| CBT vs. BT | −0.20 | 1.01 | 0.84 | −2.18, 1.78 |
| Sleep onset latency (min) | ||||
| CT vs. BT | −17.04 | 10.30 | 0.10 | −37.21, 3.14 |
| CBT vs. CT | −2.72 | 7.47 | 0.72 | −17.36, 11.93 |
| CBT vs. BT | −19.75 | 10.10 | 0.051 | −39.55, 0.05 |
| Wake after sleep onset (min) | ||||
| CT vs. BT | 8.90 | 14.48 | 0.54 | −19.48, 37.29 |
| CBT vs. CT | 4.83 | 17.77 | 0.79 | −30.00, 39.65 |
| CBT vs. BT | 13.73 | 15.68 | 0.38 | −17.00, 44.46 |
| Total Sleep Time (min) | ||||
| CT vs. BT | 23.96 | 25.83 | 0.35 | −26.67, 74.59 |
| CBT vs. CT | 0.17 | 35.06 | 0.99 | −68.53, 68.88 |
| CBT vs. BT | 24.14 | 29.68 | 0.42 | −34.03, 82.31 |
| Time in Bed (min) | ||||
| CT vs. BT | 7.95 | 17.44 | 0.65 | −26.23, 42.13 |
| CBT vs. CT | −6.21 | 27.27 | 0.82 | −59.66, 47.25 |
| CBT vs. BT | 1.74 | 26.76 | 0.95 | −50.70, 54 |
| Sleep efficiency (%) | ||||
| CT vs. BT | 4.63 | 4.23 | 0.27 | −3.66, 12.93 |
| CBT vs. CT | −0.05 | 5.98 | 0.99 | −11.77, 11.67 |
| CBT vs. BT | 4.59 | 5.46 | 0.40 | −6.12, 15.29 |
| WSAS | ||||
| CT vs. BT | −1.71 | 1.35 | 0.20 | −4.35, 0.93 |
| CBT vs. CT | 2.25 | 0.79 | 0.004 | 0.71, 3.80 |
| CBT vs. BT | 0.54 | 1.30 | 0.68 | −2.01, 3.10 |
| MFI | ||||
| CT vs. BT | −1.39 | 2.19 | 0.53 | −5.67, 2.90 |
| CBT vs. CT | −1.80 | 1.89 | 0.34 | −5.50, 1.90 |
| CBT vs. BT | −3.19 | 2.06 | 0.12 | −7.23, 0.86 |
| SF-36 – Physical | ||||
| CT vs. BT | 7.25 | 3.77 | 0.06 | −0.15, 14.65 |
| CBT vs. CT | −6.22 | 4.74 | 0.19 | −15.52, 3.07 |
| CBT vs. BT | 1.03 | 4.32 | 0.81 | −7.44, 9.49 |
| SF-36 – Mental | ||||
| CT vs. BT | 8.01 | 4.87 | 0.10 | −1.54, 17.56 |
| CBT vs. CT | −12.62 | 4.46 | 0.005 | −21.36, −3.88 |
| CBT vs. BT | −4.61 | 4.35 | 0.29 | −13.13, 3.92 |
Note. Significant p-values are bolded. SE = standard error. ISI = Insomnia Severity Index. CT = cognitive therapy. BT = behavior therapy. CBT = cognitive behavior therapy. Min = minutes. WSAS = Work and Social Adjustment Scale. MFI = Multidimensional Fatigue Inventory. SF-36 - Physical = SF-36 Health Survey - Physical Component. SF-36 - Mental = SF-36 Health Survey - Mental Component. Coefficients represent time-by-condition-by-comorbidity interactions for continuous outcomes and condition-by-comorbidity interactions for binary outcomes. For interactions, the first treatment listed represents the reference group (e.g., for “CT vs. BT,” the reference group is CT). For time and psychiatric comorbidity, pre-treatment and no comorbidity are the reference groups.