EARLY SESSION EFFECTS OF CBT-I ON INSOMNIA AND DEPRESSION

Abstract Introduction Cognitive behavioral therapy for insomnia (CBT-I) has been shown to reduce depressive symptomatology among patients with co-occurring insomnia and depression. Brief forms of CBT-I have been tested in various settings including primary care. As delivery formats of CBT-I broaden, it is important to enhance our understanding of what doses and what components of CBT-I, provide the optimal balance of treatment efficacy and brevity. In the present study, we examine session-by-session effects of CBT-I on insomnia and depression. Methods Fifty-four Veterans with insomnia and co-occurring depression or posttraumatic stress disorder were randomized to either four sessions of CBT-I or treatment as usual in a published parent study. We report here on the effects among those who received CBT-I (n =22). At each session participants provided a completed sleep diary and completed the Insomnia Severity Index (ISI) and Patient Health Questionnaire-9 for depression (PHQ-9). Results At baseline, participants endorsed a moderate level of both insomnia (ISI score = 18.5 [SD=4.2]) and depression (PHQ-9 score = 15.6 [SD=5.2]). A mean decrease of 4.0 points in ISI total score was observed between sessions 1 and 2 [t(21)=-3.88, p<.001] and a 3.3 points between sessions 2 and 3 [t(19)=-2.63, p<.05]. Mean PHQ-9 scores decreased by 2.9 points between sessions 1 and 2 [t(21)=-2.84, p<.01] and a 2.8 points between sessions 2 and 3 [t(19)=-2.77, p<.05]. In contrast, changes in ISI and PHQ-9 scores between baseline and session 1, and sessions 3 and 4 did not reach significance. Conclusion The majority of improvements in both insomnia and depression were observed following sessions 1 and 2 of CBT-I. Findings suggest that even a limited exposure to CBT-I may have a clinically significant impact on functioning across multiple domains. Whether such early improvements represent an optimal balance compared with the more modest additional improvements achieved by adding more sessions is discussed. Support This work was supported by the VISN 2 Center of Excellence for Suicide Prevention at the Canandaigua VAMC.