The goal of this clinical study is to investigate the neural mechanisms of abnormal sensory phenomena in patients with Obsessive-Compulsive Disorder and to evaluate whether modulation of the insula-supplementary motor area circuit can improve these symptoms. The study will include adult patients with OCD (with or without sensory phenomena) and healthy volunteers.
The main questions it aims to answer are:
* Do patients with OCD show abnormal activity in the insula-SMA circuit compared with healthy controls? * Is this abnormality associated with the presence and severity of abnormal sensory phenomena? * Can low-frequency rTMS targeting the Supplementary Motor Area improve sensory phenomena and obsessive-compulsive symptoms? Researchers will compare an on-line rTMS group (viewing body-focused videos during stimulation) with an off-line rTMS group (resting during stimulation) to evaluate whether task engagement enhances treatment effects.
Participants will:
* Complete clinical assessments and behavioral tasks. * Undergo EEG and fMRI assessments. * Receive low-frequency rTMS targeting the Supplementary Motor Area. * Repeat assessments after the intervention.
Meet the diagnostic criteria for Obsessive-Compulsive Disorder according to Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition.
Aged 18-55 years.
Score ≥16 on the Yale-Brown Obsessive Compulsive Scale, indicating moderate to severe symptoms.
Score >6 on the Sensory Phenomena Scale (SPS), indicating moderate to severe sensory phenomena.
Meeting diagnostic criteria in Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition for psychiatric disorders other than OCD or obsessive-compulsive personality disorder.
OCD symptoms so severe that required assessments cannot be completed.
Presence of severe suicidal ideation or high suicide risk.
Pregnant women or women planning pregnancy in the near future.