Aim and Background: Insomnia, one of the prevalent disorders, in many cases is considered as a sign associated with physical and mental disorders. The present study aimed to investigate the effectiveness of Cognitive-Behavioral Group Therapy on these symptoms among male prisoners. Methods and Materials: subjects of this experimental study were 28 male prisoners in central prison of Shiraz who were randomly assigned to experimental and control groups. The experimental group participated in 9 cognitive behavioral group therapy sessions, while the control group received no treatment. The participants completed Pittsburgh Sleep Quality Index, Beck Depression Inventory, and Beck Anxiety Inventory. Data was analyzed using Analysis of Covariance. Results: High percentage of prisoners reported insomnia symptoms. Moreover, the results of Analysis of Covariance showed that cognitive behavioral group therapy could decrease insomnia symptoms in post-test (p<0.01) and follow-up (p<0.05) stages. Conclusion: Taking into account the high prevalence of insomnia among prisoners and effectiveness of Cognitive-Behavioral Group Therapy on its symptoms, it seems necessary to carry out more research and provide psychological services to decrease insomnia symptoms and its underlying factors.
