Major depressive disorder (MDD) is a highly prevalent and debilitating condition that reduces quality of life, increases health care utilization, markedly impairs social/occupational functioning, and enhances suicide risk for countless individuals worldwide. A substantial proportion of MDD patients present with comorbid insomnia that significantly complicates their clinical management. For many such patients, insomnia represents a longstanding and problematic condition that predates the onset of MDD, adds to their suicide risk, dampens their response to traditional depression treatment, and enhances the likelihood for MDD relapse. Moreover, many patients who show remission of depressive symptoms with traditional therapies (e.g., antidepressant medications, cognitive therapy) suffer from residual insomnia that increases their chances for eventual relapse. Despite the deleterious effects insomnia may have on MDD patients, there has been surprisingly little research to test effective insomnia management strategies among this patient group. Some reports suggest that depression treatments may benefit from adding a hypnotic medication to traditional depression therapy, but this approach has it limits since sleep improvements achieved with hypnotics do not endure after hypnotic discontinuation. Cognitive-Behavioral Insomnia Therapy (CBT-I) represents a promising alternative treatment for MDD since it is highly effective and produces sleep improvements that persist well beyond the discontinuation of acute therapy. Unfortunately CBT-I has yet to be tested among MDD patients with comorbid insomnia. In the current project, we will conduct a randomized clinical trial to test the efficacy of CBT-I when used in isolation or in combination with antidepressant medication (escitalopram) among MDD patients with comorbid insomnia. A sample of 201 patients with MDD and comorbid insomnia will be randomized to treatments consisting of the combination of antidepressant medication plus CBT-I, antidepressant medication plus placebo behavioral insomnia therapy, or CBT-I plus a placebo medication. Objective (polysomnography, actigraph) and subjective (sleep diary, questionnaires) sleep measures, as well as depression and quality of life measures will be obtained before therapy, after an 8-week treatment phase, and at 6-months follow-up. Results of this trial will provide important new information about the short and long-term management of those highly challenging and difficult to treat patients with insomnia comorbid to MDD.

Hypothesis I asserts that the combined CBT-I+AD therapy will produce significantly greater pre-to-post therapy improvements in sleep continuity measures than will the 2 mono-therapy conditions. The primary outcomes for these hypotheses are subjective (sleep diary) measures of TWT and SE. These sleep measures are recorded daily for 2-week periods at baseline, post-treatment, and the 6-month follow-up. The daily measures will be averaged over each 2-week period. As a result, patients will have three repeated outcomes for each of the two sleep measures: one representing the average at baseline, one for the average at post-treatment, and one for the average at 6-months. Sleep diary estimates of TWT and SE from pre to post treatment will serve as the primary measures to test this hypothesis. Our secondary outcome measures include diary estimates of total sleep time (TST), as well as objective measures of TWT, SE, \& TST taken from pre-and post-treatment PSG and actigraphic monitoring We will use a 3 (treatment groups) x 2 (Baseline vs. post-treatment) Analysis of Variance (ANOVA) model to compare the performance of our treatment conditions across the primary and secondary outcomes. Treatment comparisons of CBT-I + AD vs. each of the other 2 treatments will be made. Alpha for the 2 primary outcomes is fixed at 0.025 (= 0.05/2). Further analyses will adjust for pre-treatment stratification variables and other covariates. The investigators will, in particular, be mindful of the treatment adherence and credibility data we collect and use these measures as covariates if the investigators find differential adherence or credibility rates across treatment conditions. In addition, the investigators will explore the effect of changes in medication on the observed changes in our outcome measures by considering medication usage data derived from the MQS106.