KMAN Publication Inc. (KMANPUB) Journal of Adolescent and Youth Psychological Studies (JAYPS) 2981-2526 6 Serial Number 36 2025 08 10 Effectiveness of Cognitive Behavioral Therapy on Sleep Quality and Quantity in Adolescents with Depressive Symptoms Effectiveness of Cognitive Behavioral Therapy on Sleep Quality and Quantity in Adolescents with Depressive Symptoms 1 8 10.61838/kman.jayps.4268 EN Journal Article 2025 04 08 ABSTRACT Objective: This study aimed to evaluate the effectiveness of cognitive behavioral therapy (CBT) on improving the quantity and quality of sleep in adolescents with depressive symptoms. Methods and Materials: The study employed a quasi-experimental pre-test–post-test design with a control group. The statistical population consisted of 4,137 middle and high school students in Khalkhal, Iran, during the 2024–2025 academic year. A total of 40 adolescents showing symptoms of depression were selected using convenience sampling and randomly assigned to an experimental group (n = 20) and a control group (n = 20). The intervention consisted of eight 70-minute CBT sessions delivered weekly. Data were collected using the Pittsburgh Sleep Quality Index (PSQI) and the Beck Depression Inventory (BDI), and analyzed using one-way analysis of covariance (ANCOVA). Findings: ANCOVA results showed that the intervention had a statistically significant effect on both sleep quantity (F = 24.296, p < 0.001) and sleep quality (F = 22.224, p < 0.001), after controlling for pre-test scores. The experimental group demonstrated significant post-test improvements in both variables compared to the control group, indicating the effectiveness of CBT in enhancing sleep outcomes among adolescents with depressive symptoms. Conclusion: Cognitive behavioral therapy is effective in improving both sleep quantity and quality in adolescents experiencing symptoms of depression. These findings support the application of structured CBT interventions within adolescent mental health services, particularly for addressing sleep-related issues associated with mood disturbances.

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