Augmentation effect of repetitive transcranial magnetic stimulation over the orbitofrontal cortex in drug-resistant obsessive-compulsive disorder patients: a controlled investigation.

Background: The orbitofrontal cortex (OFC) plays a major role in the pathophysiology of obsessive-compulsive disorder (OCD); functional neuroimaging studies indicate that OCD symptoms are associated with increased activity in the OFC, caudate nucleus, thalamus, and anterior cingulate gyrus. The goal of our single-blind study was to assess whether repetitive transcranial magnetic stimulation (rTMS) over the left OFC would influence OCD symptoms in drug-resistant patients.
Method: Twenty-three consecutively admitted right-handed inpatients with DSM-IV-TR-diagnosed drug-resistant OCD were given rTMS (80% motor threshold, 1 Hz seconds per minute for 10 minutes every day for 15 days) to the left OFC parallel (active: n = 16) or perpendicular (sham: n = 7) to the scalp. The patients' OCD symptoms, mood, and anxiety were rated at baseline, at the end of treatment, and once every 2 weeks for 3 months after treatment. Data were gathered from June 2006 to November 2007.
Results: Considering changes in Yale-Brown Obsessive Compulsive Scale (YBOCS) scores with 2-way analysis of variance for repeated measures for a total of 8 observations (before rTMS, after treatment, and every 2 weeks for 12 weeks' follow-up), we found significant reduction of YBOCS scores comparing active versus sham treatment for 10 weeks after the end of rTMS (P < .02), with loss of significance after 12 weeks (P < .06). We also found a reduction of anxiety and depression symptoms but not a significant difference in the 2 groups.
Conclusions: Low-frequency rTMS of the left OFC produced significant but time-limited improvement in OCD patients compared to sham treatment.