The effects of a smartphone cognitive behavioural therapy application on insomnia symptoms in children: a randomised controlled trial and mediation analysis.

Trial Arm 1. Intervention group: Sleep Ninja is an automated smartphone app co-designed with 12-16-year-olds and parents to deliver CBT-I. It is free and publicly available for devices using iOS and Android operating systems. Given its gamified features and content reading level (Years 5-6), Sleep Ninja is suitable for 10–12-year-olds. Sleep Ninja has been further adapted to a younger age group with parent input to involve parents in the intervention. The program includes 6 modules (referred to as ‘training sessions’), a sleep tracking function, sleep scheduling based on required wake time, personalised wind-down routine and reminders, a series of sleep tips, sleep meditation and general information about sleep. The app uses gaming elements to enhance engagement, based on a Ninja analogy. Users complete training sessions to increase their sleep skills, allowing them to “level up” (move to the next level), and finish the program with a black belt in sleep. Each training session takes approximately 5-10-mins to complete and covers a core CBT-I strategy delivered through an automated chat-bot where the Ninja acts as a sleep coach. Components include sleep scheduling and circadian rhythms (training 1), stimulus control (training 2), daytime functioning and the pre-bed routine (training 3), cognitive therapy to address worries at night (training 4), planning for high-risk situations (training 5), and a final review session (training 6). Users progress through the app by completing each training session and tracking their sleep for 3 nights (out of a 7-night period). Interaction with other functions within the app (e.g., bedtime mediation, sleep tips, general sleep information) are at the users discretion. The use of Sleep Ninja is self-guided, allowing the user to choose the duration and frequency of use, however, it is recommended users complete at least one training session per week. Sleep Ninja is designed to be used during the day and not at bedtime to prevent screen time and blue light interference with sleep. Integration of parents in the intervention includes encouraging and assisting their child to complete the training sessions and sleep tracking, and supporting their child to implement the CBT-I strategies learnt during the sessions (e.g., implementing the Sleep Ninja recommended sleep routine, implementing the pre-bed winddown, removing sleep deterrents (devices) from the bedroom, managing unhelpful beliefs about sleep). During the trial, use of Sleep Ninja will be restricted to 6-weeks for participants in Trial Arm 1, however, on completion of the trial participants will have unlimited access to Sleep Ninja. Adherence to the intervention will be measured using the Treatment Adherence and Satisfaction Questionnaire.