This study explores the mechanisms of change in a six-week online acceptance and commitment therapy (ACT) intervention for adults experiencing both subclinical and clinical insomnia. It specifically investigates how changes in psychological processes and symptoms, such as thought suppression, mindfulness, and depressive symptoms, mediate the intervention’s effects on subjective sleep complaints. The findings indicate that reductions in thought suppression and depressive symptoms contributed to improved sleep complaints.
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Key findings
- Reductions in thought suppression and depressive symptoms: The online ACT intervention led to decreases in thought suppression and depressive symptoms, which in turn reduced subjective sleep complaints.
- There was no significant mediation by mindfulness or dysfunctional beliefs about sleep: Changes in mindfulness, overall psychological distress, or dysfunctional beliefs about sleep were not found to mediate the intervention’s effects.
- Effectiveness of online ACT: The intervention was effective in alleviating subjective sleep complaints, demonstrating its potential as an accessible option for insomnia treatment.
Recommendations
- Incorporating ACT principles, particularly those targeting thought suppression and acceptance, may offer an effective approach for managing insomnia.
- Clinicians should focus on reducing experiential avoidance, such as thought suppression, and increasing acceptance of distressing experiences to improve sleep-related outcomes.
- Online ACT interventions can be a valuable tool for reaching individuals who might not have access to face-to-face therapy, though further research is encouraged to refine population-specific approaches and mechanisms.
Reference
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, 2868. https://doi.org/10.1038/s41598-025-87018-3
