ACT for insomnia: what recent research says about an emerging alternative to CBT-I

Cognitive behavioural therapy for insomnia (CBT-I) remains the first-line treatment for chronic insomnia, but it is not a panacea. Non-response and attrition rates remain high, and certain populations struggle to adhere to its counterintuitive behavioural strategies, such as sleep restriction and stimulus control. Acceptance and commitment therapy (ACT), with its emphasis on experiential acceptance and values-based living, is now emerging as a promising adjunct or alternative approach. In this article, we review findings from three recent studies that examine ACT for insomnia in depth: a clinical review of ACT vs CBT-I (Saldaña et al., 2023), an online intervention randomised controlled trial examining mechanisms of change (Hämäläinen et al., 2025), and a pilot head-to-head comparison between ACT and CBT-I (Shin et al., 2023).

Why ACT for insomnia?

Sleep is an involuntary physiological process, yet insomnia is often maintained by effortful attempts to control sleep. Cognitive arousal, sleep-related worry, and suppression of unwanted thoughts contribute to this paradox. ACT, by targeting psychological inflexibility, may reduce these forms of cognitive-emotional entanglement. Across studies, key ACT processes such as acceptance, defusion, and willingness have been associated with improved sleep quality, reduced sleep effort, and better adherence to behavioural components of treatment.

Key study 1: ACT as an adjunct or alternative to CBT-I (Saldaña et al., 2023)

Saldaña and colleagues provide a narrative review comparing components of ACT and CBT-I alongside research outcomes. They highlight the challenge of treatment adherence in CBT-I, particularly during the early stages of sleep restriction. ACT-based protocols, such as the ABC-I model, have been developed to integrate core ACT processes (acceptance, mindfulness, values) alongside behavioural sleep strategies.

This review noted that pilot studies using ACT-enhanced protocols showed high adherence, low dropout rates, and improved sleep quality among individuals who had previously dropped out of CBT-I. These findings suggest that the ACT stance of “making room” for discomfort may increase willingness to engage in otherwise aversive behavioural components.

Importantly, ACT appears especially beneficial for individuals with trauma histories, chronic pain, or rigid beliefs about sleep. The authors argue that ACT’s non-pathologising stance and emphasis on lived experience may be better suited to culturally diverse populations who might not resonate with cognitive restructuring. It is worthy noting this was not a systematic review and therefore there is an increased risk of bias within the literature presented.

This paper provides some really nice examples of metaphors and their adaption for use in this population, as well as directly comparing some approaches to particular thoughts that show up within this population. See here for the full paper.

Key study 2: online ACT for insomnia – mechanisms of change (Hämäläinen et al., 2025)

This randomised controlled trial evaluated a six-week self-guided ACT program for adults with clinical or subthreshold insomnia. The study’s primary aim was to identify mechanisms of change in ACT by testing mediators such as thought suppression, mindfulness, dysfunctional beliefs about sleep, and depressive symptoms. The study included 86 adults, who were randomly allocated equally to either intervention or a waitlist control group. Only 39 participants from the intervention group completed the study to the 6 month follow-up.

Findings showed that:

• Decreased thought suppression and depressive symptoms significantly mediated reductions in subjective sleep complaints (thought suppression; r = .47, p ≤ .001 & depression symptoms r = .29, p = .01).
• Changes in mindfulness and dysfunctional sleep beliefs were not significant mediators in this study.
• The intervention produced significant decreases in subjective sleep scores across total effects including direct and indirect measures (p = .006).

This supports the ACT model: attempting to control or eliminate unwanted internal experiences (e.g., insomnia-related thoughts) paradoxically increases arousal and distress. Reducing suppression and increasing acceptance may facilitate sleep onset by allowing de-arousal and decoupling from control-based strategies.

Interestingly, the study found no evidence that dysfunctional beliefs about sleep mediated change – a key target of CBT-I. This aligns with ACT’s emphasis on changing the function, not content, of thoughts.

Key study 3: ACT vs CBT-I in head-to-head pilot (Shin et al., 2023)

This pilot RCT directly compared ACT and CBT-I over a four-week mixed-format intervention (four in-person sessions, four online). Both interventions produced significant improvements in insomnia severity, sleep efficiency, and depression. However, ACT alone significantly reduced anxiety related to sleep, while CBT-I did not.

Effect sizes suggested:

• CBT-I had greater impact on dysfunctional sleep beliefs (consistent with its mechanism).
• ACT had greater impact on depression and anxiety.

These findings have important implications. Anxiety is a known perpetuating factor in insomnia, and ACT may be particularly effective where hyperarousal, emotional dysregulation, or trauma history are central. ACT’s ability to shift clients from an outcome-focused stance (“I must sleep”) to a process-focused one (“I can engage in meaningful life even when tired”) may reduce the very pressure that impairs sleep.

How ACT helps with insomnia: core processes at work

We pulled together this simple summary to consider the 6 core processes within ACT and how these can be applied to sleep improvement.

 

Key recommendations:

Taken together, the research points to ACT as a credible, flexible, and values-aligned intervention for insomnia. While CBT-I remains highly effective, its structure and cognitive emphasis may not suit all clients. ACT offers an alternative model that does not rely on controlling sleep, thoughts, or emotions, but instead focuses on relating differently to them.

Emerging evidence supports ACT both as a stand-alone and adjunctive intervention, particularly for those who:

• Have high anxiety or trauma-related sleep disruption
• Struggle with thought suppression or experiential avoidance
• Find traditional cognitive restructuring unhelpful
• Drop out of or cannot access CBT-I

Join us this November when we host Maja Schaedel for ACT for insomnia & sleep difficulties. Learn strategies to address cognitive & behavioural factors inhibiting sleep for your clients.

References

Saldaña, K. S., McGowan, S. K., & Martin, J. L. (2023). Acceptance and Commitment Therapy as an Adjunct or Alternative Treatment to Cognitive Behavioral Therapy for Insomnia. Sleep medicine clinics, 18(1), 73–83. https://doi.org/10.1016/j.jsmc.2022.09.003

Hämäläinen, T., Lappalainen, P., Langrial, S. U., Lappalainen, R., & Kiuru, N. (2025). Mechanisms of change in an online acceptance and commitment therapy intervention for insomnia. Scientific reports, 15(1), 2868. https://doi.org/10.1038/s41598-025-87018-3

Shin, J. W., Kim, S., Shin, Y. J., Park, B., & Park, S. (2023). Comparison of Acceptance and Commitment Therapy (ACT) and Cognitive Behavior Therapy (CBT) for Chronic Insomnia: A Pilot Randomized Controlled Trial. Nature and science of sleep, 15, 523–531. https://doi.org/10.2147/NSS.S409981

Resources related to ACT for insomnia: what recent research says about an emerging alternative to CBT-I