In the Volume 7 Number 6 issue of Journal of Clinical Sleep Medicine Rachel Manber and a group of researchers from Stanford University and Rush University Medical Center report a study comparing the response of clients with high and low depressive symptom severity to cognitive behavioral therapy for insomnia (CBT-I). Treatment was 7 sessions of group therapy for insomnia in which depressive symptoms were not directly addressed. A cutoff score of 14 or above on the Beck Depression Inventory was used to define participants as having a high level of depressive symptoms.
Results suggest that pre- to post CBTI improvements in insomnia symptoms, perceived energy, productivity, self-esteem, and other aspects of well-being were similar for the 120 subjects in the high depressive symptom group and the 181 subjects in the low depressive symptom group. This suggests that the benefits of CBT-I extend beyond insomnia and include improvements in non-sleep related outcomes. The rate of reduction in insomnia severity was clinically equivalent across both groups, with the high depression group having more severe insomnia both before and after treatment. All participants were originally referred for treatment for insomnia and were treated in the same groups as the categorization was performed post hoc. These findings pertain only to patients who complete treatment, which is an important limitation because previous research suggests that elevated symptoms of depression at baseline increases risk of early termination from group CBT-I.