RecruitingBehavioural interventionEfficacy of CBT-I With Adjuvant Melatonin in Older Adults Chronic InsomniaThis 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.