Bipolar disorder (BD) is a debilitating
mood disorder marked by manic, hypomanic and/or mixed or depressive episodes. It affects approximately 1-2% of the population and is linked to high rates of suicide, functional impairment and poorer quality of life. Presently, treatment options for BD are limited. There is a strong evidence base for pharmacological (e.g.,
lithium) and psychological (e.g., psychoeducation) treatments; however, both of these pose challenges for treatment outcomes (e.g., non-response, side-effects, limited access). Repetitive
transcranial magnetic stimulation (rTMS), a non-invasive brain stimulation technique, is a recommended treatment for
unipolar depression, but it is unclear whether rTMS is an effective, safe and well tolerated treatment in people with BD. This article reviews the extant literature on the use of rTMS to treat BD across different mood states. We found 34 studies in total (N = 611 patients), with most assessing
bipolar depression (n = 26), versus bipolar
mania (n = 5), mixed state bipolar (n = 2) or those not in a current affective episode (n = 1). Across all studies, there appears to be a detectable signal of efficacy for rTMS treatment, as most studies report that rTMS treatment reduced bipolar symptoms. Importantly, within the randomised controlled trial (RCT) study designs, most reported that rTMS was not superior to
sham in the treatment of
bipolar depression. However, these RCTs are based on small samples (NBD ⩽ 52). Reported side effects of rTMS in BD include
headache,
dizziness and sleep problems. Ten studies (N = 14 patients) reported cases of affective switching; however, no clear pattern of potential risk factors for affective switching emerged. Future adequately powered,
sham-controlled trials are needed to establish the ideal rTMS treatment parameters to help better determine the efficacy of rTMS for the treatment of BD.