Group-Based Brief Behavioral Therapy for Insomnia for Patients With Chronic Mental Illness

The goal of this clinical trial is to evaluate the effectiveness of a short-term, group-based Brief Behavioral Therapy for Insomnia (BBTI) intervention in chronic psychiatric patients at a hospital day ward.The main questions it aims to answer are: 1. Does the BBTI-based group intervention improve subjective sleep quality and reduce the severity of insomnia? 2. Does the intervention have a positive effect on psychological well-being and cardiometabolic/physical functions? Researchers will compare an experimental group to a waitlist control group to see if the intervention improves sleep quality, reduces insomnia-perpetuating behaviors, and enhances overall health status across various timeframes. Participants will: 1. Attend four sessions that cover sleep structure education, relaxation techniques (including acupressure), sleep-promoting diet principles, and the proper use of sedative-hypnotic medications. 2. Write a daily sleep diary. 3. Complete three times of structured self-report questionnaires. 4. Undergo physiological and physical function assessments.

Inclusion Criteria: * Aged 18 years and older. * Diagnosed with a psychiatric disorder. * Experiencing self-reported sleep disturbances, such as difficulty initiating sleep, difficulty maintaining sleep, early morning awakening, prolonged sleep latency, short sleep duration, poor sleep efficiency, or the current use of sedative-hypnotic medications. Exclusion Criteria: * Severe intellectual disability resulting in the inability to complete the assessment questionnaires. * Severe cognitive impairment (e.g., dementia) that prevents cooperation and participation in the intervention activities. * Recent clinical instability, high suicide risk, or deemed unsuitable for participation by the primary attending physician.