Use of Transcranial Magnetic Stimulation in Bipolar Disorder

[...] there are now 30 published randomized, controlled trials and 10 meta-analyses that have reported on the antidepressant effects of transcranial magnetic stimulation (TMS) in patients with unipolar depression.3 In 2008, the U.S. Food and Drug Administration approved TMS for the treatment of unipolar major depression in adult patients who have failed to respond to a single adequate antidepressant medication trial.3 TMS affects neural activity at the site of stimulation and in distal regions that are interconnected and are implicated in mood disorders, such as the striatum, thalamus, and anterior cingulate cortex.3 Imaging studies of mood disorders point to dysfunction of the limbic and prefrontal cortex activity.1 Depression syndromes may be associated with low cortical activity (blood flow and metabolism), particularly on the left side, with relative increase on the right side.1 On the basis of results of unipolar depression studies, it has been hypothesized that left-sided dorsolateral prefrontal cortex stimulation via TMS-induced neuronal depolarization may change brain activity and improve mood.3 although the anatomo-pathophysiology of bipolar disorder may be somewhat different, affecting right- as well as left-sided systems, few studies have examined the therapeutic effects of TMS in bipolar depression.