Background: Obsessive-compulsive disorder (OCD) is a debilitating neuropsychiatric disorder that affects approximately 2-3% of the world population. The first-line treatments are selective serotonin reuptake inhibitors and cognitive behavioral therapy. Despite that, approximately 40- 60% of patients remain treatment refractive.
Aim of work: Evaluating the efficacy of different frequencies of repetitive transcranial magnetic stimulation (rTMS) applied over the right dorsolateral prefrontal cortex (DLPFC) as an adjunctive treatment for resistant OCD.
Patient and Methods: Thirty patients with treatment resistant OCD were randomly assigned to 2 weeks either active LF (1 Hz, n=10), HF (10 Hz, n=10) with parameters (25-minute trains, 1,500 pulses/day at 100% of the resting motor threshold RMT, 5 sessions/week) or sham (n=10) (same HF parameters with coil tilting). OCD, anxiety and depressive symptoms were assessed using: Yale-Brown Obsessive Compulsive Scale (Y-BOCS), Hamilton Anxiety Scale (HAM-A), Beck Depression Inventory (BDI) and Clinical Global Impression-Severity scale (CGI-S) before and immediately after sessions and 3 months later.
Results: A repeated-measures analysis of variance (ANOVA) revealed a non-significant reduction in Y-BOCS scores in the active groups compared with the sham group after 2 weeks and 3 months later. Similarly, there was non-significant effect of time and time×group interaction on scores of (HAM-A) (CGI-S). While there was a significant effect of time and time×group interaction on scores of (BDI) after 2 weeks with active stimulation especially LF-rTMS not after 3 months. There were no reports of serious adverse effects following the active or sham rTMS treatments.
Conclusion: Neither LF nor HF rTMS over the right DLPFC appeared to be superior to sham rTMS for relieving OCD and anxiety symptoms in patients with treatment-resistant OCD. However, rTMS has a role in improving depressive symptoms, especially with LF-rTMS. Further trials with larger sample sizes should be conducted to confirm the present findings.