Co-adapting a healthy sleep intervention with adolescents: impact and process evaluation of a Health CASCADE pilot study.

backgroundCo-creation has proven effective in developing school-based healthy sleep interventions with and for adolescents. However, co-created interventions are context-specific. To increase scalability and broaden impact, co-created interventions might be adapted to new contexts via co-adaptation, defined as the collaborative tailoring of a (previously co-created) intervention to a new context. This study evaluates a co-adapted 9-week school-based healthy sleep intervention for adolescents in a three-arm pilot trial.

methodsOne school co-adapted a previously co-created intervention using Intervention Mapping. Another school implemented the original intervention with minor adjustments, while a third served as control and received no intervention. Data on sleep parameters, psychosocial determinants, and sleep-hygiene behaviours were collected via questionnaires at baseline (October 2022), post (May 2023), and follow-up (October 2023) (n = 170; 13.07 ± 0.71 years; 58.33% girls). Generalised Linear Mixed Models (GLMM) were fitted in R. Intervention acceptance was assessed in students from intervention schools through post-test questionnaires and four focus groups (n = 9, n = 2, n = 8, n = 4). Analyses were performed in MaxQDA.

resultsBoth intervention schools showed favourable effects on daytime sleepiness at follow-up and objective weekday sleep duration at post versus the control. The co-adaptation school also showed favourable effects on knowledge at post. The co-adaptation school showed favourable effects on perceived sleep quality and mental wellbeing at follow-up, but unfavourable effects on stress, screen use at follow-up, and objective weekday sleep duration at post compared to the standard school. No significant effects emerged for other sleep parameters, psychosocial determinants, or sleep-hygiene behaviours. While students in both intervention schools noted incomplete delivery, the co-adaptation school reported better intervention acceptance (e.g., perception of intervention components and lesson- and class competition delivery).

conclusionCo-adaptation may enhance intervention acceptance but requires careful cost-benefit consideration, as the standard intervention yielded similar yet smaller effects. Further research with more schools per arm is needed.

trial registrationThis study is registered as clinical trial (NCT05838339). Registration date: 07.11.2022.