Razavi Journal of Medicine

Razavi Journal of Medicine

Investigating the Effects of Repetitive Transcranial Magnetic Stimulation of the Dorsolateral Prefrontal Cortex on Response Inhibition and Cognitive Flexibility in Patients with Generalized Anxiety Disorder

Articles in Press

Document Type : Original Article

Authors
Mohsen Arshad 1
Leila Mehdizadeh Fanid 2
Soomaayeh Heysieattalab 1
Soomaayh Rabat Milli 3
Amin Amiri 4
1 Department Of Cognitive Neuroscience, University Of Tabriz, Tabriz, Iran
2 Department of Cognitive Neuroscience, Faculty of Educational Science and Psychology, University of Tabriz, Tabriz, Iran
3 Department of Psychology, Faculty of Governance, University of Tehran, Tehran, Iran.
4 Research Development Committee of Taleghani Hospital and Department of Psychiatry, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
10.30483/rjm.2026.254813.1558
Abstract
Background: Generalized anxiety disorder (GAD) is characterized by excessive, uncontrollable, and persistent worry about various life events. Evidence suggests that deficits in response inhibition and reduced cognitive flexibility contribute to the persistence of this disorder.

Objective: The present study aimed to investigate the effects of repetitive transcranial magnetic stimulation (rTMS) of the dorsolateral prefrontal cortex on response inhibition and cognitive flexibility in individuals with GAD

Method: This quasi-experimental study employed a pre-test–post-test design with a control group. The study population comprised FARAJA police officers referred to the neurology and psychiatry department of Imam Sajjad Hospital in Tehran over a nine-month period. Thirty participants were selected through convenience sampling and randomly assigned to experimental and control groups (n = 15 per group). Response inhibition was assessed using the Stroop Color–Word Test, and cognitive flexibility was assessed using the Cognitive Flexibility Inventory developed by Dennis and Vander Wal. The experimental group received 20 sessions of low-frequency (1 Hz) rTMS over the right dorsolateral prefrontal cortex at 110% of the motor threshold. Each session lasted 30 minutes, and sessions were conducted five times per week over one month.

Results: The experimental group demonstrated significantly greater improvements in response inhibition measures compared with the control group (p ≤ 0.001). Cognitive flexibility also increased significantly in the experimental group relative to the control group (p ≤ 0.001).

Conclusion: Repetitive transcranial magnetic stimulation of the dorsolateral prefrontal cortex was associated with improvements in response inhibition and cognitive flexibility in individuals with GAD. These findings suggest that rTMS may represent a potential non-invasive intervention for improving specific cognitive functions in this population. However, as anxiety symptoms were not directly assessed as outcome measures in the present analysis, the extent to which these cognitive changes relate to clinical symptom improvement remains unclear.

Trial Registration: Iranian Registry of Clinical Trials (IRCT), registration number IRCT20250129064556N1.
Keywords
Repetitive transcranial magnetic stimulation (rTMS)
response inhibition
cognitive flexibility
generalized anxiety disorder (GAD)

Acknowledgements: This article was derived from a research project. The authors sincerely thank all participants and everyone who assisted in conducting this research.


Data Availability: All data generated or analysed during this study are included in this published article.


Ethical Considerations: This study received ethical approval from the university under the code IR.TABRIZU.REC.1403.024 and registered in the Iranian Clinical Trial Registry (IRCT: 20250129064556N1). All participants provided written informed consent after the study objectives and procedures were fully explained. All procedures performed in studies involving human participants were by the ethical standards of the institutional research committee and the Declaration of Helsinki of 1964.


Consent for publication: Not applicable


Conflict of Interest: The authors declare that they have no conflicts of interest in relation to the present study.


Funding: The present study received no financial support.


Author Contributions: The first author contributed to idea development and data collection. The second and third authors contributed to idea development, supervision of the research process, and data collection. The third and fourth authors contributed to data analysis. All authors contributed to the initial drafting of the manuscript and accept responsibility for the accuracy and integrity of its contents.

Open Access Policy: This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/

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Razavi Journal of Medicine

Articles in Press, Accepted Manuscript
Available Online from 16 October 2026