Baseline symptoms of depression and anxiety negatively impact the effectiveness of CBTi in treating acute insomnia among young adults

Background Cognitive–behavioural therapy for insomnia (CBTi) is the first-line treatment for those with this sleep disorder. However, depressive and anxiety symptoms often co-occur with acute insomnia, which may affect the effectiveness of CBTi treatment.Aims This study aimed to determine the impact of depressive and anxiety symptoms on the efficacy of CBTi in treating acute insomnia.Methods A single-arm clinical trial was conducted among individuals who have acute insomnia. Participants underwent self-guided CBTi for 1-week. Their insomnia, depressive symptoms and anxiety symptoms were evaluated using the Insomnia Severity Index and the Hospital Anxiety and Depression Scale at baseline, post-treatment and 3-month follow-up. Repeated measures analysis of variance was used to assess the effectiveness of CBTi in treating insomnia, depressive symptoms and anxiety symptoms. A multivariate Cox regression model was used to determine the impact of depressive and anxiety symptoms on insomnia.Results The study found significant reductions in insomnia, depressive symptoms and anxiety symptoms at both post-treatment and 3-month follow-up (F=17.45, p<0.001; F=36.37, p=0.001; and F=81.51, p<0.001, respectively). The duration of CBTi treatment had a positive impact on insomnia recovery (hazard ratio (HR)=0.94, p=0.018). However, baseline depressive symptoms (HR=1.83, p=0.004) and baseline anxiety symptoms (HR=1.99, p=0.001) had significant negative effects on insomnia recovery.Conclusions The study showed that a 1-week self-guided CBTi treatment is effective in treating acute insomnia and comorbid depressive and anxiety symptoms. However, baseline depressive and anxiety symptoms negatively impact treatment effectiveness. Therefore, clinicians should assess for depressive and anxiety symptoms before treating acute insomnia with monotherapy CBTi.