Right prefrontal repetitive transcranial magnetic stimulation in obsessive-compulsive disorder: a double-blind, placebo-controlled study. Effect of prefrontal repetitive transcranial magnetic stimulation in obsessive-compulsive disorder: a preliminary study. Right versus left prefrontal transcranial magnetic stimulation for obsessive-compulsive disorder: a preliminary investigation.
The efficacy of repetitive transcranial magnetic stimulation (rTMS) of the right prefrontal cortex for patients with obsessive-compulsive disorder (OCD) was studied under double-blind, placebo-controlled conditions.
                Patients were randomly assigned to 18 sessions of real (N=10) or sham (N=8) rTMS. Treatments lasted 20 minutes, and the frequency was 1 Hz for both conditions, but the intensity was 110% of motor threshold for real rTMS and 20% for the sham condition.
                No significant changes in OCD were detected in either group after treatment. Two patients who received real rTMS, with checking compulsions, and one receiving sham treatment, with sexual/religious obsessions, were considered responders.
                Low-frequency rTMS of the right prefrontal cortex failed to produce significant improvement of OCD and was not significantly different from sham treatment. Further studies are indicated to assess the efficacy of rTMS in OCD and to clarify the optimal stimulation characteristics. Prefrontal mechanisms are implicated in obsessive-compulsive disorder. The authors investigated whether prefrontal repetitive transcranial magnetic stimulation influenced obsessive-compulsive disorder symptoms.
                Twelve patients with obsessive-compulsive disorder were given repetitive transcranial magnetic stimulation (80% motor threshold, 20 Hz/2 seconds per minute for 20 minutes) to a right lateral prefrontal, a left lateral prefrontal, and a midoccipital (control) site on separate days, randomized. The patients' symptoms and mood were rated for 8 hours afterward.
                Compulsive urges decreased significantly for 8 hours after right lateral prefrontal repetitive transcranial magnetic stimulation, but there were nonsignificant increases in compulsive urges after repetitive transcranial magnetic stimulation of the midoccipital site. A shorter-lasting (30 minutes), modest, and nonsignificant reduction in compulsive urges occurred after left lateral prefrontal repetitive transcranial magnetic stimulation. Mood improved during and 30 minutes after right lateral prefrontal stimulation.
                These preliminary results suggest that right prefrontal repetitive transcranial magnetic stimulation might affect prefrontal mechanisms involved in obsessive-compulsive disorder. There is preliminary evidence that repetitive transcranial magnetic stimulation (rTMS) may be useful for the treatment of obsessive-compulsive disorder (OCD), but no definitive study has been published, and the effect of laterality of stimulation is uncertain.
                Subjects (N = 12) with resistant OCD were allocated randomly to either right or left prefrontal rTMS daily for 2 weeks and were assessed by an independent rater at 1 and 2 weeks and 1 month later.
                Subjects had an overall significant improvement in the obsessions (p < .01), compulsions (p < .01), and total (p < .01) scores on the Yale-Brown Obsessive Compulsive Scale (Y-BOCS) after 2 weeks and at 1-month follow-up. This improvement was significant for obsessions (p < .05) and tended to significance for total Y-BOCS scores (p = .06) after correction for changes in depression scores on the Montgomery-Asberg Depression Rating Scale. There was no significant difference between right- and left-sided rTMS on any of the parameters examined. Two subjects (33%) in each group showed a clinically significant improvement that persisted at I month but with relapse later in I subject.
                A proportion (about one quarter) of patients with resistant OCD appear to respond to rTMS to either prefrontal lobe, although in the absence of a sham treatment group in this study, we cannot rule out the possibility of this being a placebo response. This treatment warrants further investigation to better establish its efficacy and examine the best parameters for response.
There are currently insufficient data from randomised controlled trials to draw any conclusions about the efficacy of transcranial magnetic stimulation in the treatment of obsessive-compulsive disorder.