Deep TMS May Reduce OCD Symptoms
Obsessive compulsive disorder (OCD) occurs in about 2% of the population worldwide. Selective serotonin reuptake inhibitor (SSRI) antidepressants are the most commonly used treatment for OCD, but not all patients respond adequately to them.
At the 2015 meeting of the Transcranial Magnetic Stimulation Society, researcher Joseph Zohar presented evidence that deep transcranial magnetic stimulation (deep TMS) targeted over the medial prefrontal cortex may reduce OCD symptoms. In TMS treatment, an electromagnetic coil is placed against the patient’s head and magnetic pulses that can penetrate the scalp are converted into small electrical currents that stimulate neurons in the brain. In Zohar’s study, patients with OCD were randomized to receive deep TMS at frequencies of either 20 Hz or 1 Hz, or a sham procedure. The 20 Hz deep TMS resulted in a 28% reduction in OCD symptoms compared to the other two groups, indicating that the 20 Hz treatment had a large effect size.
In addition to the deep TMS procedures, all patients also received cognitive behavioral therapy, high doses of SSRIs, and relapse prevention training.
Editor’s Note: It is interesting that 20 Hz deep TMS, which activates the prefrontal cortex, was more effective than 1 Hz, which decreases activity there. Other attempts to treat OCD have focused on suppressing frontal-striatal-thalamic circuits, which are overactive in the disorder. Since the medial prefrontal cortex is an important area for the new learning required for the extinction of anxiety symptoms in a variety of disorders, increasing activity in this medial prefrontal target area with 20 Hz may activate that extinction process allowing new learning rather than nonspecifically suppressing hyperactive frontal-striatal-thalamic circuits as 1 Hz TMS would do.