Effectiveness of Group Cognitive Behavioral Therapy on Quality of Life and Psychological Wellbeing of Patients With Parkinson Disease A Randomized Controlled Trial Jale Narimisaei, MSc,* Mahdi Naeim, PhD,† Zohreh Nasiri, PhD,‡ Shima Imannezhad, MD,§ and Yasaman Mohammadi, DDS† Abstract: This study investigates the impact of group cognitive behavioral ther- apy (CBT) on depression reduction and quality of life improvement among indi- viduals with Parkinson disease. A randomized clinical trial with pretest and post- test measurements involved 90 participants referred to Roozbeh Hospital in Tehran in 2023, who were randomly assigned to either an experimental group (n = 45) or a control group (n = 45). The experimental group underwent a 3-month CBT inter- vention comprising 12 sessions of 90 minutes each. Both groups completed the Beck Depression Inventory and the World Health Organization Quality of Life Questionnaire preintervention and postintervention. Data analysis via multivariate analysis of covariance using SPSS-25 revealed significant improvements in reduc- ing depression and enhancing quality of life in the experimental group compared with the control group (p ≤ 0.01). These findings indicate that CBT is an effective treatment for reducing depression and improving the quality of life of individuals with Parkinson disease, demonstrating its clinical applicability in therapeutic settings. Key Words: Cognitive-behavioral therapy, quality of life, depression, Parkinson (J Nerv Ment Dis 2025;00: 00–00) P arkinson disease is one of the most prevalent central nervous system disorders, second only to Alzheimer disease, and is a leading cause of disability in older adults (Dobkin et al., 2020). The risk of developing Parkinson disease rises with age, affecting approximately 1.8% of indi- viduals over the age of 65 (Ghielen et al., 2019). Parkinson disease is characterized by the gradual degeneration of dopamine-producing brain cells. Although it is primarily known as a progressive movement disor- der, cognitive and linguistic impairments are also frequently observed (Zhang et al., 2020). Key symptoms of Parkinson disease include rest- ing tremors in the hands and feet, bradykinesia (slowness of move- ment), stiffness, rigidity in the limbs and body, and impaired balance (Piers et al., 2023). Patients with Parkinson disease often require continuous care and without adequate support; they may face a higher risk of complica- tions (Luo et al., 2021). This disease not only significantly impairs pa- tients' functional abilities but also profoundly impacts their emotional, psychological, social, and overall quality of life (Hadinia et al., 2017). Quality of life is a broad concept encompassing physical, psycholog- ical, cognitive, social, cultural, and economic dimensions. Regarding physical health, functional status is a critical component (LaRocca and Scogin, 2015). Individuals' quality of life is also shaped by their capacity to maintain functional independence and engage in daily activities such as self-care, education, and employment. Psychologically, mental health is a core element of quality of life, and maintaining a pos- itive outlook can lead to significant improvements. Social and cultural factors, including family roles, social participation, and interpersonal re- lationships, also play essential roles in shaping one's overall quality of life (Da Silva et al., 2023). Among the most prominent psychological symptoms in patients with Parkinson disease are anxiety and depression, often triggered by the physical symptoms and limitations imposed by the disease. Tremors, bradykinesia, abnormal gait, freezing episodes, falls, speech difficulties, and changes in vocal tone frequently lead to feelings of embarrassment and social withdrawal, reducing motivation and willingness to partici- pate in social activities. These factors can significantly impact the quality of life for individuals with Parkinson disease. While the general public is typically aware of the motor symptoms associated with Parkinson dis- ease, fewer people realize that Parkinson disease originates in the brain, disrupting specific chemical compounds and resulting in early symp- toms such as sleep disturbances and mild depression (Chen et al., 2021). Sleep disturbances are reported by 60%–98% of individuals with Parkinson disease, a prevalence rate higher than that found in similarly aged individuals without the disease. Patients frequently report symp- toms including insomnia, excessive daytime drowsiness, and difficulty with sleep onset and maintenance, as well as sleep apnea, restless leg syndrome, mood disturbances, and periodic limb movements during sleep. Despite the significant prevalence of these symptoms, few stud- ies have comprehensively addressed the issue (Piers et al., 2022). Cognitive-behavioral therapy (CBT) is one of the psychological approaches that have attracted significant attention from researchers and clinicians over recent decades (Berardelli et al., 2018). CBT is gen- erally considered a short-term, skills-focused intervention designed to modify maladaptive emotional responses by altering thought patterns, behaviors, or both. The core premise of CBT is that cognition, emotion, and behavior are interrelated, with changes in one domain influencing the others (Amoke et al., 2020). Group-based CBT is particularly cost- effective in terms of both time and resources compared with individual therapy and has been widely used as a complementary treatment for patients with chronic physical conditions. Given the development of numerous CBT models and treatment protocols for various mental dis- orders and chronic medical conditions and their proven efficacy in clin- ical research, the current study aims to investigate the effectiveness of group CBT in reducing depression and improving quality of life among individuals with Parkinson disease. NECESSITY OF CONDUCTING THE STUDY This study addresses a significant gap in the existing literature by investigating the effectiveness of group-based CBT specifically de- signed for individuals with Parkinson disease. While previous studies have primarily examined the efficacy of individual CBT in treating de- pression and enhancing quality of life among Parkinson disease pa- tients, few have specifically explored the impact of group-based therapy *Department of Computer, Energy, and Data Science Faculty, Behbahan Khatam Alanbia University of Technology, Behbahan, Iran; †Department of Research, Psychology, and Counseling Organization, Tehran, Iran; ‡Torbat Jam Faculty of Medical Sciences, Torbat Jam, Iran; and §Department of Pediatrics, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran. Send reprint requests to Yasaman Mohammadi, DDS, Department of Research, Psychology, and Counseling Organization, 16th Street, Jannat Street, Amirabad, Tehran, Iran 14399-53151. E‐mail: ymohammadi573@gmail.com. Copyright © 2025 Wolters Kluwer Health, Inc. All rights reserved. ISSN: 1539-736X/25/0000–0000 DOI: 10.1097/NMD.0000000000001822 ORIGINAL ARTICLE The Journal of Nervous and Mental Disease • Volume 00, Number 00, Month 2025 www.jonmd.com 1 Copyright © 2025 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.