0415 Predictors of treatment response and remission after CBT-I among adolescents with insomnia and eveningness

Abstract Introduction Despite the efficacy of cognitive behavioural therapy for insomnia (CBT-I) for treating youth insomnia, there remain individual differences in treatment outcomes. Previous studies found that demographic (e.g., age) and clinical features (e.g., depression, anxiety) could potentially affect treatment responses in adults but there has been limited research conducted in youth. This study aimed to identify potential predictors of treatment response and remission of insomnia following CBT-I in a sample of adolescents with insomnia and eveningness. Methods The sample consisted of 57 adolescents with insomnia with eveningness (Age: 20.21 ± 1.95, 15-24, female: 56.14%) who had completed a 6-session group-based cognitive behavioural therapy (CBT-I) with (n = 27) or without bright light therapy (n=30). Assessments were conducted at baseline and one-week post-intervention. Insomnia Severity Index (ISI) was used to measure self-reported insomnia symptoms. Treatment response was defined as a reduction in ISI score ≥ 6 after treatment, and remission was defined as an ISI score < 9 at post-treatment. Backward stepwise logistic regression was conducted to explore baseline demographic and clinical factors (e.g., comorbid depression or anxiety, suicidality) that might contribute to treatment response and remission of insomnia. Results About 64.9% and 68.4% of the participants achieved treatment response and remission of insomnia, respectively. There was no significant difference in response (60.0% vs. 73.4%) and remission (63.3% vs. 74.1%) rates between participants with and without adjunctive light therapy. Treatment response was significantly predicted by lower suicidality (p<.05) and less eveningness (p<.05), while being male (p=.09) and having greater insomnia symptoms (p=.06) were associated with treatment response at a marginal significance. Participants with older age (p<.05) and greater insomnia symptoms (p<.05) were more likely to achieve a remission. Moreover, greater anxiety symptoms (p=.09) and adjunctive bright light therapy (p=.07) predicted insomnia remission with a trend towards significance. Conclusion CBT-I is more effective in adolescents with less eveningness, elevated insomnia symptoms, and less suicidality. Future research should explore whether addressing these factors in the delivery of CBT-I could improve treatment outcomes in youths with insomnia. Support (if any) This work was funded by General Research Fund (Ref. 17608918), Research Grants Council, University Grants Committee, Hong Kong SAR, China.