Chronic insomnia is one of the most common health complaints in the world, and for more than two decades the first-line answer has been cognitive behavioral therapy for insomnia, widely abbreviated as CBT-I. Yet a quiet debate has been building among sleep researchers about what exactly belongs inside that treatment package. In a letter published in the Journal of Clinical Sleep Medicine, Andrea Ballesio of Sapienza University of Rome argues that acceptance and commitment therapy, known as ACT, should not be pushed to the margins of insomnia care, even as new evidence forces clinicians to think carefully about how it is combined with the standard behavioral components of CBT-I.
The letter responds directly to an updated meta-analysis by Barroso and colleagues, published in the same journal, which pooled results from randomized controlled trials of acceptance and commitment therapy for insomnia. Meta-analyses of this kind are considered the highest tier of evidence because they aggregate data across many independent trials, smoothing out the noise of individual studies to reveal whether an effect is real and how large it is. The publication of an updated synthesis is significant because the last wave of ACT-for-insomnia trials had produced a mixed picture, with some studies showing strong benefits and others showing effects that faded or failed to separate from control conditions.
To understand why this matters, it helps to look at the technical anatomy of CBT-I itself. The treatment is not a single technique but a multi-component protocol. Its core is stimulus control, which re-associates the bed with sleep by restricting activities such as reading or worrying in bed, and sleep restriction therapy, which deliberately limits time in bed to consolidate fragmented sleep into a denser, more efficient block. Around this core sit cognitive restructuring, which challenges dysfunctional beliefs about sleep, relaxation training, and sleep hygiene education. Decades of trials, summarized in meta-analyses such as the 2019 review by van der Zweerde and colleagues, show that these effects are durable, persisting for months after treatment ends, and clinical guidelines from the American College of Physicians and the European Sleep Research Society both recommend CBT-I as the first-line treatment for chronic insomnia in adults.
ACT approaches the problem from a different psychological angle. Rather than trying to eliminate unwanted thoughts about sleep, ACT teaches patients to accept the presence of arousal and sleep-related worry without struggling against it, while committing to behaviors aligned with their values regardless of how a given night unfolds. The theoretical rationale is that the effort to control sleep itself, checking the clock, calculating remaining hours, ruminating over the consequences of a bad night, fuels the hyperarousal that keeps insomniacs awake. By defusing from these thoughts and reducing experiential avoidance, ACT aims to break the vicious cycle in which anxiety about sleep produces the very wakefulness it fears.
The question raised by the new meta-analysis is whether this mechanism translates into measurable sleep improvements when ACT is tested on its own. Ballesio’s letter, as its title suggests, answers with a qualified yes. The argument is not that ACT should replace the behavioral core of CBT-I, but that it retains a meaningful role, particularly when integrated with the sleep-scheduling components that have the strongest evidence base. The letter points to a randomized controlled pilot trial by Hertenstein and colleagues published in Psychotherapy and Psychosomatics in 2024, which combined acceptance and commitment therapy with bedtime restriction and compared it against full CBT-I, finding that the hybrid approach was feasible and showed promising signals on both sleep and psychological outcomes.
This matters because insomnia rarely exists in isolation. Large meta-analytic work, including the 2015 JAMA Internal Medicine analysis by Wu and colleagues, has shown that CBT-I improves sleep in people whose insomnia is comorbid with psychiatric and medical conditions, from depression to chronic pain. More recent syntheses, including a 2026 systematic review by Fiori, Lombardo, Baglioni and Ballesio, indicate that treating insomnia with cognitive behavioral therapy also produces long-term benefits for depressive symptoms, suggesting that sleep treatment has ripple effects across mental health. If a substantial subgroup of patients responds better to acceptance-based strategies than to cognitive restructuring, then a one-size-fits-all version of CBT-I may leave therapeutic value on the table.
There is also a biological dimension to the debate. A 2023 meta-analysis by He and colleagues examined CBT-I in patients with the objective short sleep duration phenotype, the subgroup of insomniacs whose polysomnography shows genuinely reduced sleep even as they report severe insomnia. This phenotype is thought to reflect heightened physiological hyperarousal and carries elevated cardiometabolic risk. Acceptance-based interventions, which specifically target autonomic and cognitive arousal rather than sleep-related beliefs alone, are theoretically well suited to this group, and the letter suggests that phenotype-informed treatment selection could become a productive direction for the field.
Access and scalability add a further practical layer. A 2025 debate piece in the journal Sleep by Espie, Grandner and Drake argued that CBT-I can and should be delivered by a broad range of healthcare providers, not only specialized psychologists, because demand vastly outstrips the supply of trained therapists. In that context, the modular structure of insomnia treatment becomes an asset: if acceptance and commitment strategies can be packaged alongside sleep restriction and stimulus control, or offered in digital and group formats, they may extend the reach of effective care. The letter’s intervention can be read as a defense of that flexibility, warning against narrowing the CBT-I umbrella to a single orthodox recipe.
None of this means the evidence for standalone ACT is settled. The letter acknowledges that the updated meta-analysis by Barroso and colleagues tempers some of the earlier enthusiasm, and that trials directly comparing ACT-augmented protocols against gold-standard CBT-I remain scarce, small, and heterogeneous in how they define and deliver the acceptance component. The honest reading of the current literature is that acceptance and commitment therapy is best supported as an adjunct, layered onto the behavioral backbone of insomnia treatment, rather than as a standalone substitute. Ballesio’s argument is essentially a call for precision: the field should stop asking whether ACT works for insomnia in the abstract and start asking for whom, in what combination, and through which mechanisms.
For patients, the practical takeaway is that the conversation about ACT is happening inside a treatment framework that already works well. CBT-I remains the guideline-endorsed first-line therapy, with effects that outlast most pharmacological options and without the dependence risks of hypnotic medication. What the letter adds is a roadmap for making that framework more adaptable, preserving the behavioral techniques with the strongest evidence while leaving room for acceptance-based strategies where hyperarousal, comorbidity, or patient preference call for them. As the field moves toward larger head-to-head trials and phenotype-matched treatment algorithms, the debate over ACT’s place in CBT-I is less a challenge to the standard of care than an attempt to sharpen it.
Subject of Research: The role of acceptance and commitment therapy within cognitive behavioral therapy for insomnia
Article Title: Why we should still ACT in CBT-I
Article References: Ballesio, A. (2026). Why we should still ACT in CBT-I. Journal of Clinical Sleep Medicine, 22(1), Article 187. https://doi.org/10.1007/s44470-026-00206-4
Image Credits: AI Generated
DOI: 10.1007/s44470-026-00206-4
Keywords: insomnia, CBT-I, acceptance and commitment therapy, sleep restriction, meta-analysis, cognitive behavioral therapy, hyperarousal, sleep medicine, psychotherapy, clinical guidelines, randomized controlled trials, mental health
News Source: Ophelia Keating. (October 7, 2026). Acceptance Therapy Still Earns Its Place in Insomnia Treatment, Scientist Argues. Scienmag.



