Adherence to cognitive behavioral therapy for insomnia: a systematic review

Chronic insomnia is a significant public health problem worldwide, and insomnia has considerable personal and social costs associated with serious health conditions, greater healthcare utilization, work absenteeism, and motor-vehicle accidents. Cognitive behavioral therapy for insomnia (CBTI) is an efficacious treatment, yet attrition and suboptimal adherence may diminish its impact. Despite the increasing use of CBTI, surprisingly little attention has been devoted to understanding the role of adherence. This review describes a comprehensive literature search of adherence to CBTI. The search revealed 15 studies that evaluated adherence to CBTI in adults using valid and reliable measures of sleep, and measure of adherence other than study withdrawals. The primary purposes of this review were to 1) synthesize current study characteristics, methodology, adherence rates, contributing factors, and impact on outcomes, 2) discuss measurement issues, and 3) identify future practice and research directions that may lead to improved outcomes. Strong patterns and inconsistencies were identified among the studies, which complicate an evaluation of the role of adherence as a factor and outcome of CBTI success. The importance of standardized adherence and outcome measures is discussed. In light of the importance of adherence to behavior change, this systematic review may better inform future intervention efforts.