Evidence and characteristics of Acceptance and Commitment Therapy (ACT)-based interventions for insomnia: A systematic review of randomized and non-randomized trials

Insomnia is a sleep disorder frequently associated with the impairment of physical and mental health. Cognitive-Behavioral Therapy for Insomnia (CBT-I) is the treatment of choice, but this therapy has some limitations. Acceptance and Commitment Therapy (ACT) is a promising therapy because it is aimed at improving psychological flexibility instead of focusing on symptom control. This systematic review assessed the levels of evidence and the characteristics of interventions using ACT for insomnia as the primary outcome. The PubMed, PsyInfo, and Scopus databases were searched following the PRISMA statement. Articles published in English using ACT-based interventions with insomnia as the primary outcome were included. One hundred and five articles were identified and eleven were included in the systematic review. Of these, six were randomized and five were non-randomized trials. Seven studies combined ACT with behavioral and/or cognitive components, while four used only ACT. The results of the included articles showed that ACT reduces the severity of insomnia and is associated with improved sleep patterns. This modality is applied in different formats and with different intervention components. ACT is used for the treatment of insomnia both as monotherapy (ACT-I) and combined with behavioral components of stimulus control and sleep restriction (ACT-BBI-I). ACT-I is a possibly efficacious treatment for insomnia, while ACT-BBI-I is a probably efficacious treatment for insomnia. ACT-based interventions can serve as treatment alternatives for insomnia and contribute to the construction of a process-based approach.