Transdiagnostic Modular Sleep Intervention Was Associated With Improved Sleep and Reduced Psychiatric Symptom Severity in Patients With Psychiatric Disorders

Objective: This study aimed to evaluate the preliminary effectiveness of a five-session modular cognitive behavioral therapy for insomnia (CBT-I)– based sleep intervention in psychiatric outpatients presenting with sleep complaints.Methods: Fifty-six psychiatric outpatients (mean age 39.38±15.30 years; 16 men) with clinically diagnosed psychiatric disorders and insomnia symptoms or related sleep disturbances participated. The program consisted of sleep hygiene education (Sessions 1–2) followed by the modular CBT-I–based sleep intervention (Sessions 3–5) tailored to the primary sleep problem. Nine standardized questionnaires were administered at baseline (T0), post-intervention (T1), and 3-month follow-up (T2; n=20). Participants completed a sleep diary during treatment; 41 met criteria for early- versus late-treatment diary analyses (T0 vs. T1). Questionnaire outcomes were analyzed using linear mixed-effects models, and diary parameters using paired t-tests.Results: Improvements were observed at T1 across multiple domains, including insomnia severity (Insomnia Severity Index), sleep quality (Pittsburgh Sleep Quality Index), fatigue (Fatigue Severity Scale), anxiety (Beck Anxiety Inventory), depression (Patient Health Questionnaire-9), and health-related quality of life (36-Item Short Form Health Survey) (all p<0.001). These improvements were largely sustained at the 3-month follow-up. Sleep diary analyses showed increased mean sleep efficiency (SE) (p<0.001) and significantly reduced wake after sleep onset (WASO), nap time (NT), and snoozing (p<0.01 for WASO and NT; p<0.05 for snoozing). Reduced SE variability (p=0.01) was consistent with enhanced sleep stability, while time in bed and WASO variability showed positive improvement trends (p<0.10).Conclusion: In this single-arm outpatient study, the modular CBT-I–based sleep intervention was associated with improvements in subjective sleep and diary-derived sleep continuity. These findings suggest that a modular CBT-I–based sleep intervention may be a feasible adjunctive approach for improving sleep and psychiatric symptoms in routine psychiatric outpatient care.