Efficacy of cognitive behavioral therapy for comorbid insomnia: a meta-analysis

Although cognitive behavioral therapy (CBT-I) has been recommended for the treatment of insomnia comorbid with psychiatric disorders and medical diseases, the effectiveness of CBT-I in such cases remains to be established. To fill this gap in the literature, we conducted a meta-analysis on the efficacy of CBT-I in the remediation of insomnia severity, important disease-related symptoms, and quality of life (QoL) in comorbid insomnia. A comprehensive literature search identified 30 randomized controlled trials (RCT) that were eligible for inclusion in the final analyses. Effect sizes were computed with Hedges’g, and study quality was evaluated using the Jadad scale. Analysis revealed that the effect sizes of the treatment were medium to large for important disease-related symptoms (g = 0.60), insomnia severity (g = 0.94), subjective and objective sleep onset latency (g = 0.65 and g = 0.51, respectively), subjective waking after sleep onset (g = 0.61), subjective and objective sleep efficiency (g = 0.83 and g = 0.48, respectively), and sleep quality (g = 0.80), but was small for health-related QoL (g = 0.34) compared with a control group. At follow-up, the effect sizes of CBT-I were large for all outcome variables, but several large and significant heterogeneities were confirmed. CBT-I is an effective treatment for reducing the severity of insomnia and important disease-related symptoms of comorbid insomnia.