Repetitive transcranial magnetic stimulation (rTMS) is a noninvasive Food and Drug Administration (FDA)-approved treatment for unipolar treatment-resistant depression (TRD). rTMS has been utilized clinically to treat bipolar TRD; however, there remains a lack of evidence and support for effectively utilizing this intervention for bipolar TRD. We retrospectively analyzed data from a group of patients who were treated with rTMS for unipolar or bipolar TRD and describe a case example to further delineate management techniques for employing rTMS in the treatment of bipolar TRD.
Records of 71 patients treated with rTMS for unipolar (n=54) or bipolar (n=17) TRD between 2008 and 2017 were reviewed. The primary outcome of depression severity, the Quick Inventory of Depressive Symptomatology, was completed at baseline and after every 5 sessions throughout the course of 30 treatments. Secondary outcomes involved a comparison of outcomes and clinical characteristics within and between the bipolar and unipolar TRD groups.
In the total sample, patients’ depression improved significantly over the course of treatment. Patients with bipolar TRD showed greater response and remission rates over the course of treatment compared with patients with unipolar TRD, but this difference was not statistically significant. Both groups showed a similar pattern of depression response over treatment time. No manic or hypomanic episodes occurred during any patient’s course of rTMS treatment. A case example is provided discussing the timing of rTMS in a patient with bipolar depression to decrease the likelihood of treatment-induced hypomania.
Limitations included the small overall sample size, the smaller size of the patient group with bipolar TRD compared with the group with unipolar TRD, and the naturalistic setting of this study.
Our data suggest that rTMS may be equally effective and safe for patients with both unipolar and bipolar depression. Patients with bipolar TRD showed a similar response profile over treatment time compared with patients with unipolar TRD.