Cognitive Behavioral Therapy for Insomnia Comorbid With Psychiatric and Medical Conditions

IMPORTANCE: Cognitive behavioral therapy for insomnia (CBT-I) is the most prominent nonpharmacologic treatment for insomnia disorders. Although meta-analyses have examined primary insomnia, less is known about the comparative efficacy of CBT-I on comorbid insomnia. OBJECTIVE: To examine the efficacy of CBT-I for insomnia comorbid with psychiatric and/or medical conditions for (1) remission from insomnia; (2) self-reported sleep efficiency, sleep onset latency, wake after sleep onset, total sleep time, and subjective sleep quality; and (3) comorbid symptoms. DATA SOURCES: A systematic search was conducted on June 2, 2014, through PubMed, PsycINFO, the Cochrane Library, and manual searches. Search terms included (1) CBT-I or CBT or cognitive behavioral and its variations or behavioral therapy and its variations or behavioral sleep medicine or stimulus control or sleep restriction or relaxation therapy or relaxation training or progressive muscle relaxation or paradoxical intention; and (2) insomnia or sleep disturbance. STUDY SELECTION: Studies were included if they were randomized clinical trials with at least one CBT-I arm and had an adult population meeting diagnostic criteria for insomnia as well as a concomitant condition. Inclusion in final analyses (37 studies) was based on consensus between 3 authors' independent screenings. DATA EXTRACTION AND SYNTHESIS: Data were independently extracted by 2 authors and pooled using a random-effects model. Study quality was independently evaluated by 2 authors using the Cochrane risk of bias assessment tool. MAIN OUTCOMES AND MEASURES: A priori main outcomes (ie, clinical sleep and comorbid outcomes) were derived from sleep diary and other self-report measures. RESULTS: At posttreatment evaluation, 36.0% of patients who received CBT-I were in remission from insomnia compared with 16.9% of those in control or comparison conditions (pooled odds ratio, 3.28; 95% CI, 2.30-4.68; P < .001). Pretreatment and posttreatment controlled effect sizes were medium to large for most sleep parameters (sleep efficiency: Hedges g = 0.91 95% CI, 0.74 to 1.08; sleep onset latency: Hedges g = 0.80 95% CI, 0.60 to 1.00; wake after sleep onset: Hedges g = 0.68; sleep quality: Hedges g = 0.84; all P < .001), except total sleep time. Comorbid outcomes yielded a small effect size (Hedges g = 0.39 95% CI, 0.60-0.98; P < .001); improvements were greater in psychiatric than in medical populations (Hedges g = 0.20 95% CI, 0.09-0.30; χ2 test for interaction = 12.30; P < .001). CONCLUSIONS AND RELEVANCE: Cognitive behavioral therapy for insomnia is efficacious for improving insomnia symptoms and sleep parameters for patients with comorbid insomnia. A small to medium positive effect was found across comorbid outcomes, with larger effects on psychiatric conditions compared with medical conditions. Large-scale studies with more rigorous designs to reduce detection and performance bias are needed to improve the quality of the evidence.