Metacognitive therapy for insomnia: An open cohort study on clinical outcomes and the role of cognitive-attentional syndrome factors in insomnia

Background: Insomnia is a common and distressing disorder. Evidence suggests that metacognitive beliefs and maladaptive strategies, such as worry and rumination, may maintain insomnia. Objectives: This study is the first trial of metacognitive therapy (MCT) for insomnia. It aimed to evaluate the effects of MCT on insomnia severity and examine how cognitive-attentional syndrome (CAS) components predict these changes. Methods: An uncontrolled open cohort trial was conducted with 31 participants in a clinic setting. Participants received up to ten MCT sessions and completed weekly measures of insomnia severity, anxiety, depressive symptoms, and metacognitive beliefs, including maladaptive strategies. The primary outcome was remission status from pre-to post-treatment. Associations between components of the cognitive-attentional syndrome (CAS) and insomnia severity were examined using a mixed model. Follow-up data were collected at 3, 6, and 12 months. Results: At post-treatment, 57 % of participants met remission criteria and 67 % scored below the clinical cut-off. Within-group effect sizes were large for the Insomnia Severity Index (Hedges' g = 1.64) and moderate for anxiety (HADS-A, g = 0.67) and depression (HADS-D, g = 0.72). Among those providing follow-up data, 87.5 % remained at or further improved their insomnia symptoms by their last assessment. Moreover, both between-person averages and within-person changes in maladaptive CAS strategies significantly predicted ISI scores, whereas only within-person changes in CAS-negative metacognitions reached significance. Conclusions: These preliminary findings indicate that metacognitive therapy (MCT) shows promise as an intervention for insomnia. However, large-scale, controlled trials are necessary to further evaluate its clinical utility for this condition.