RESUMEN
OBJECTIVE: Sleep and circadian disturbance is highly comorbid with a range of psychological disorders, especially major depressive disorder (MDD). In view of the complexity of sleep and circadian problems in MDD, this study aimed to evaluate the efficacy of a group-based transdiagnostic intervention for sleep and circadian dysfunction (TranS-C) for improving depressive symptoms and sleep and circadian functions. METHOD: One hundred fifty-two adults diagnosed with comorbid MDD and sleep and circadian dysfunctions were randomized into TranS-C group treatment (TranS-C; n = 77) or care as usual (CAU; n = 75) control group. The TranS-C group received six weekly 2-hr group sessions of TranS-C, whereas the CAU group continued to receive usual care. Assessments were at baseline, immediate (Week 7), and 12-week (Week 19) posttreatment. Primary and secondary outcomes included depression, anxiety, sleep disturbances, fatigue, quality of life, and functional impairment. RESULTS: The TranS-C group showed significant improvement in depressive symptoms (p < .001, d = 0.84), insomnia severity (p < .001, d = 0.77), sleep disturbances (p < .001, d = 1.15), sleep-related impairment (p < .001, d = 1.22), fatigue (p < .001, d = 1.06), anxiety symptoms (p = .004, d = 0.67), quality of life (p < .001, d = 0.71), and sleep diary-derived parameters (ps < .05, d = 0.12-0.77) relative to the CAU group at immediate posttreatment. These treatment gains remained significant at 12-week follow-up. Significant improvement in functional impairment was also noted at 12-week follow-up. CONCLUSIONS: TranS-C was efficacious and acceptable in alleviating depressive symptoms and sleep and circadian disruptions in adults with MDD. The group format appears to be a low-cost, widely disseminable option to deliver TranS-C. Further research on TranS-C to examine its benefits on other psychiatric disorders is warranted. (PsycInfo Database Record (c) 2024 APA, all rights reserved).