Obsessive-Compulsive Disorder (OCD) is a chronic, relapsing neuropsychiatric disorder characterised by intrusive thoughts (obsessions) and repetitive behaviours (compulsions). It affects 2–3% of the population and significantly impairs personal, occupational, and social functioning. While selective serotonin reuptake inhibitors (SSRIs) and cognitive behavioural therapy (CBT) are first-line treatments, approximately 40% of patients are refractory to these interventions. Despite advancements in pharmacotherapy and psychotherapy, treatment-resistant OCD remains a major clinical challenge. Functional neuroimaging implicates hyperactivity in the cortico-striato thalamo-cortical (CSTC) circuit, particularly the supplementary motor area (SMA), in pathophysiology of OCD. Non-invasive brain stimulation techniques, such as repetitive transcranial magnetic stimulation (rTMS), have demonstrated potential in modulating these circuits through stimulation of neuroanatomical targets implicated in OCD. Deep TMS is FDA-approved for OCD and the most evidence-based TMS approaches target the right dorsolateral prefrontal cortex (DLPFC) and supplementary motor area using inhibitory protocols, with good response in 40–50% of patients.

Theta burst stimulation (TBS), a patterned form of rTMS, can induce neuroplastic changes in a shorter duration and at lower intensities. Continuous TBS (cTBS) offers inhibitory effects and has shown promise when applied to SMA. Recent international studies and systematic review report that accelerated TBS protocols—multiple daily sessions over a short span are safe, well-tolerated, and result in faster clinical improvement. However, there is a critical lack of studies from India evaluating accelerated cTBS in OCD. Additionally, Indian healthcare systems can benefit from shorter-duration interventions to improve accessibility and adherence. Thus, this randomised controlled study will assess the role of sequential accelerated cTBS over Right DLPFC, followed by Bilateral SMA (supplementary motor area), and compare it with sham stimulation, potentially offering a safe and rapid-acting adjunct treatment for OCD.