The current archival analyses examine the direct and indirect effects of cognitive behavioral therapy for insomnia (CBT-I) on depression in cancer survivors.
We report on 67 cancer survivors from a 2 × 2 randomized controlled trial of CBT-I and armodafinil for insomnia, after collapsing across the noneffective study medication conditions (armodafinil/placebo) to create CBT-I (yes/no). Depression and insomnia were assessed before, during the 7-week CBT-I intervention, at postintervention, and 3 months later by the Patient Health Questionnaire and the Insomnia Severity Index, respectively.
Mean depression at baseline for all participants was 6.44 (standard error = 0.41, range 0–15). Paired t tests showed that depression improved from baseline to postintervention by 48% (P < .001) in the CBT-I group versus 15% (P = .016) in the non-CBT-I group. Analysis of covariance controlling for baseline found that participants receiving CBT-I had significantly less depression at postintervention (effect size = −0.62; P = .001), compared to those who did not receive CBT-I. These benefits were maintained at the 3-month follow-up. Spearman rank correlations showed that changes in insomnia severity from baseline to postintervention were significantly correlated with concurrent changes in depression (r = .73; P < .001). Path analysis revealed that improvement in depression was mediated by improvement in insomnia severity (P < .001).
Our findings provide preliminary support that in cancer survivors, CBT-I reduces depression via improvement in insomnia. Further, this reduction in depression remained stable 3 months after completing CBT-I. This suggests that a CBT-I intervention has a meaningful effect on depression.
Peoples AR, Garland SN, Pigeon WR, Perlis ML, Wolf JR, Heffner KL, Mustian KM, Heckler CE, Peppone LJ, Kamen CS, Morrow GR, Roscoe JA. Cognitive behavioral therapy for insomnia reduces depression in cancer survivors. J Clin Sleep Med. 2019;15(1):129–137.