Overview
This study tests the efficacy of cognitive behavioural therapy for insomnia (CBT-I) with or without adjunct melatonin in older adults with insomnia. Adults aged 60 or above with chronic insomnia will be randomly assigned to one of three groups: (1) CBT-I plus nightly melatonin, (2) CBT-I plus nightly placebo tablet, or (3) sleep health psychoeducation plus nightly placebo tablet. All group sessions occur weekly for four weeks.
Description
This randomized, double-blind, placebo-controlled trial examines whether cognitive behavioural therapy for insomnia (CBT-I) with or without adjunct melatonin improves sleep and circadian outcomes as well as daytime functioning in older adults with chronic insomnia.
Eligible participants (aged ≥60 years, meeting DSM-5 criteria for insomnia disorder) will be recruited and randomly assigned to one of the three parallel groups: (1) CBT-I combined with nightly melatonin, (2) CBT-I with nightly placebo, or (3) sleep-health psychoeducation with nightly placebo. All interventions involve four weekly 90-minute group sessions (6-8 participants per group) conducted in person. Melatonin (3 mg immediate-release) or a matched placebo will be taken 30 minutes before habitual bedtime for four weeks.
Assessments will be conducted at baseline, mid-treatment (week 2, for the primary outcome only), and post-treatment (week 4) for all participants, and additionally at three-month and six-month follow-ups for participants in the two CBT-I groups. Data collection includes validated questionnaires on sleep, circadian, mood, fatigue, and quality of life, as well as computerized cognitive tasks to assess domains such as attention, working memory, and executive function. Objective sleep and circadian parameters will be measured by actigraphy for seven consecutive nights, along with a daily sleep diary. Participants will also complete polysomnography (PSG) for objective sleep assessment. To index circadian timing, a subset of participants will collect saliva samples (about 1 mL each) every 30 minutes under dim-light conditions in the evening to estimate dim-light melatonin onset (DLMO).
The primary outcome is the change in self-reported insomnia severity from baseline to post-treatment. Secondary outcomes include resumption and treatment response of insomnia, clinical symptom severity, objective and subjective sleep- and circadian-related outcomes, mood, daytime functioning, quality of life, and cognitive performance.
The study is conducted across two sites - The University of Hong Kong (Department of Psychology) and The Chinese University of Hong Kong (Department of Psychiatry). Findings are expected to clarify whether melatonin can augment the efficacy and sustainability of CBT-I in older adults, providing new insights into circadian-based strategies for improving sleep health in late life.
Eligibility
Inclusion Criteria:
- Chinese aged ≥ 60.
- Provision of written informed consent.
- Having a DSM-5 diagnosis of insomnia disorder (i.e., having difficulty initiating sleep, maintaining sleep, or early morning awakening at least three times a week for at least three months, with clinically significant impairment or distress).
- Having a score of \> 14 on the ISI, indicating clinical insomnia.
Exclusion Criteria:
- Having a current diagnosis or a history of manic or hypomanic episodes, schizophrenia spectrum disorders, neurodevelopmental disorders, neurocognitive disorders, organic mental disorders, intellectual disabilities, or substance abuse or dependence.
- Having a progressive medical condition directly related to the onset and course of insomnia (e.g., cancer, chronic pain).
- Undergoing treatment for diseases known to affect sleep (e.g., chemotherapy).
- Having an untreated sleep disorder that may disrupt sleep continuity and quality (e.g., sleep-disordered breathing) except for insomnia disorder.
- Having mild to significant cognitive impairment, defined by having a score of \< 22 on MOCA.
- Concurrent and regular use of extraneous melatonin or melatonin agonist (e.g., ramelteon).
- Receiving concurrent psychological treatment for insomnia.
- Meeting potential contraindications for melatonin (e.g., undergoing dialysis) or concurrently using medications that have a potential drug interaction with melatonin (e.g., anticoagulant and anti-platelet).
- Being a night shift worker.
