This study will be a randomised controlled trial to investigate an integrated platform that incorporates ecological momentary assessments/interventions (EMA/I) into cognitive behavioural therapy for insomnia (CBT-I) using mHealth and wearable technology. The intervention is a promising prospect to address current challenges in the context of sleep medicine to provide real-time and real-world intervention with accuracy, low cost, and easy accessibility.

It will be a randomised, assessor-blind controlled trial embedding both outcome and process evaluation, of the EMA/I CBT-I in conjunction with wearable sensors. The outcome evaluation will examine the treatment effect of EMA/I CBT-I compared with care-as-usual (CAU), whilst process evaluation will enhance the understanding of the causal assumptions that underpin EMA/I CBT-I to inform policy and clinical practice. 60 eligible participants will be randomly assigned to the EMA/I CBT-I group and CAU in a 1:1 allocation ratio. The participants in the EMA/I CBT-I group will receive 6 weeks of smartphone-based EMA/I CBT-I supported by a therapist. The trained therapist will prescribe EMI, provide personalised sleep advice, and adjust the treatment by dynamically adapting real-time rest-activity assessments collected using EMA and wearable devices. Assessments will be managed by an independent assessor (a research assistant) who is blind to group allocation at baseline, week 7 (1 week after treatment), and week 18 (12 weeks after treatment). The proposed study will follow the recommendations of the Consolidated Standards of Reporting Trials (CONSORT) and will be registered on ClinicalTrials.gov to ensure compliance with study design and results reporting requirements. The treatment will be provided free of charge.

Inclusion Criteria:

1. Hong Kong residents at least 18 years of age;
2. able to read Chinese and type in Chinese or English;
3. meet the DSM-5 diagnostic criteria of insomnia disorder (difficulty initiating and/or maintaining sleep or early morning awakening, alongside clinically significant daytime impairment) based on the Brief Insomnia Questionnaire (BIQ), a diagnostic tool validated by the team;
4. have an Insomnia Severity Index (ISI) score of at least 10 indicating clinical-level insomnia;
5. have adequate opportunity and circumstances for sleep to occur;
6. have an Internet-enabled mobile device (iOS or Android operating system), and
7. are willing to provide informed consent.

Exclusion Criteria:

To mimic real-world settings, a less stringent set of exclusion criteria will be adopted.

1. A Beck Depression Inventory (BDI-II) Item 9 score of at least 2 indicating a current moderate suicidal risk that requires active crisis management (referral information to professional services will be provided to those with serious suicidal risk);
2. involvement in CBT-I in the past 6 months;
3. a history of severe mental illness (e.g., bipolar disorder, psychotic disorder);
4. major medical or neurocognitive disorders or side effects of medication that contribute significantly to insomnia or make participation infeasible based on the team's clinical experience;
5. other untreated sleep disorders, including narcolepsy, obstructive sleep apnoea (OSA), and restless leg syndrome (RLS)/periodic leg movement disorder (PLMD) based on the cut-off scores (≥7 on narcolepsy; ≥15 on OSA; ≥7 on RLS/PLMD) in SLEEP-50;
6. taking over-the-counter medication or psychotropic drugs that target insomnia within 2 weeks prior to the baseline assessment; and
7. shift work, pregnancy, family or other commitments that interfere with regular sleep-wake patterns.