To Örebro University

Objectives/Introduction: Cognitive behavioural therapy for insomnia (CBT-I) is the first-line treatment for insomnia. Although 80% improve, 50% do not reach full remission. This study aimed to investigate the characteristics of patients who continue to report insomnia after CBT-I.

Methods: Secondary analyses of a randomized controlled trial in Swedish primary care that included 165 patients with insomnia disorder. The intervention was seven sessions of nurse-administrated CBT-I as group treatment over ten weeks. The control condition was treatment as usual. Remission from insomnia was assessed by the yes-or-no question ‘Would you say that you have insomnia?’ at post-treatment.

Results: At post-treatment, insomnia was reported by 95% in the control group (56 of 59), and by 57% in the intervention group (41 of 72). Patients who still reported insomnia after CBT-I had poorer mental health at baseline than those reporting remission (depressive symptoms, p = 0.006; psychological distress, p = 0.026; mental functioning, p = 0.048). They improved similarly to those reporting remission in sleep onset latency, time awake after sleep onset, sleep duration, sleep efficiency, awakenings, and sleep quality (p > 0.1, respectively), fatigue, psychological distress, depressive symptoms, and mental functioning (p > 0.2, respectively). They improved less in insomnia severity (p = 0.001), dysfunctional beliefs about sleep (p < 0.001), and use of hypnotics (p = 0.014). Change in depressive symptoms during treatments mediated between CBT-I and remission of insomnia in a model that took depressive symptoms and insomnia severity at baseline into account (direct effect, b = −2.58, CI −3.99, −1.16; indirect effect, b = −1.64, CI −3.38, −0.81). Depressive symptoms at baseline (- b = 0.32, p < 0.001) was a significant predictor of remission, but insomnia severity was not (- b = 0.08, p = 0.265).

Conclusions: Although CBT-I improved sleep and daytime symptoms, the degree of depressive symptoms prior to treatment, as well as change in depressive symptoms during treatment, affected whether patients reported that they still suffered from insomnia or not. These findings highlight the importance of careful assessment of patients with insomnia in primary care and suggest tailored treatment for patients with pronounced depressive symptoms.