Keywords: Adolescents, chronic pain, insomnia, person-centred care, school-nurses 

Introduction and Objectives: Insomnia symptoms are prevalent among adolescents experiencing chronic pain, underscoring the critical need for early intervention. This study aimed to evaluate the secondary effects of the Help Overcoming Pain Early (HOPE) intervention on insomnia symptoms and self-rated health. Methods: This study utilized aggregated data from a prior randomized controlled trial, including both the active and control groups, where the control group later received the HOPE intervention. Symptoms of insomnia were evaluated using the Minimal Insomnia Symptom Scale, while self-rated health was assessed with a single item at three time points: at the outset of the intervention, post-intervention, and at a six-month follow-up. Baseline variables encompassed age, gender, pain location, pain's impact, school attendance, and symptoms of depression (measured via the Center for Epidemiological Studies Depression Scale for Children). Linear Mixed Models (LMM) were employed for inferential analysis, and Cohen’s d was calculated to gauge effect sizes. Results: Statistically significant enhancements in insomnia symptoms emerged at the six-month follow-up, along with significant improvements in self-rated health both at the intervention's conclusion and the six-month follow-up. Despite statistical significance, effect sizes remained small for all outcomes and assessment points. Discussion and Conclusion: This study demonstrated modest yet statistically significant improvements in insomnia symptoms and self-rated health among adolescents grappling with chronic pain after undergoing the HOPE intervention. While the need for cautious interpretation of these findings persists, they underscore the potential value of a concise, easily accessible early intervention within a school-based context