According to foreign medical studies, substance use is closely related to reward sensitivity and sleep patterns. The purpose of this research is to understand the relationship between these three factors, which will help improve medical treatment and overall care for substance misuse in the future. Participants will be randomized into CBTi and sleep education groups, and their substance/ alcohol use, sleep parameters and reward sensitivity will be measured at multiple time points.

The study will invite approximately 154 individuals who have misused alcohol or drugs in the past three months and have symptoms of insomnia to participate. After completing the screening, participants who meet the study criteria will be asked to fill out five additional research questionnaires and take a 15-minute computer-based reward sensitivity test. Participants will then be randomly assigned, in a 1:1 ratio, to one of the following groups:

1. A three-session cognitive behavioral therapy (CBT) group (the first session lasts 60 minutes, with subsequent sessions not exceeding 30 minutes) and two follow-up phone calls (each lasting around 20 minutes).
2. A three-session sleep education group (the first session lasts 60 minutes, with subsequent sessions not exceeding 30 minutes) and two follow-up phone calls (each lasting around 20 minutes).

All participants will be invited to complete additional research questionnaires and computer-based tests in the 4th and 8th weeks after the group sessions begin.

Inclusion Criteria:

1. Individuals who receive treatment services at Substance Abuse Assessment Clinic and other psychiatric out-patient clinics of Kwai Chung Hospital;
2. Individuals who have problematic substance or alcohol use in the past 3 months, confirmed by scores higher than or equal to 1 in both part 1 and part 2 of Tobacco, Alcohol, Prescription medication, and other Substance use (TAPS);
3. Individuals who have sleep disturbances, confirmed by a score higher than or equal to 8 on the Insomnia Severity Index (ISI).

Exclusion Criteria:

1. Individuals who cannot understand Cantonese, or cannot read Traditional Chinese
2. Individuals who cannot provide informed consent due to, for example, intoxication or abnormal mental state
3. Individuals who report abnormal or unstable mental states, such as active psychotic symptoms or acute intoxication, at any point of the study
4. Individuals who work overnight or have rotating shifts
5. Individuals who report pregnancy or medical conditions (including sleep apnea) that may have a severe impact on sleep
6. Individuals who use hypnotics regularly

IPD will not be shared because of organizational policy.