Augmented intermittent theta-burst stimulation of the left dorsolateral prefrontal cortex for cognitive dysfunction in stable-phase schizophrenia: protocol for a randomized, double-blind, sham-controlled trial

Background: Schizophrenia is a severe mental disorder affecting approximately 1% of the global population, characterized by three core symptom domains: positive symptoms, negative symptoms, and cognitive dysfunction. Repetitive transcranial magnetic stimulation (rTMS) has emerged as a promising intervention for both positive and negative symptoms in schizophrenia. However, its therapeutic potential for cognitive dysfunction remains inconclusive. Methods: This randomized, double-blind, sham-controlled trial will enroll 70 medication-stable patients meeting DSM-5 criteria for schizophrenia. Participants will be randomly allocated (1:1) to receive either active or sham augmented intermittent theta-burst stimulation (iTBS) targeting the left dorsolateral prefrontal cortex (DLPFC). The treatment protocol consists of 600 pulses per session, three sessions per day, for 10 consecutive weekdays. Clinical symptoms will be evaluated with the Positive and Negative Syndrome Scale (PANSS), cognitive function will be assessed using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), and neural activity will be measured via functional near-infrared spectroscopy (fNIRS) during a semantic verbal fluency task. All patients will be assessed at baseline and post-intervention. Ethics and dissemination: The trial protocol complies with the principles of the Declaration of Helsinki and has been approved by the Ethics Committee of Zigong Mental Health Center (approval number: 20250802). The findings of this trial will be published and made publicly accessible in a peer-reviewed journal. Discussion: This study aims to provide strong evidence supporting the therapeutic potential of augmented iTBS for improving cognitive functioning in schizophrenia, offering a potential new treatment option for patients with schizophrenia. Clinical Trial Registration: https://www.chictr.org.cn/index.html, identifier ChiCTR2500107943.