Could bipolar depressed patients respond better to rTMS than unipolar depressed patients? A naturalistic,...

Previous studies of rTMS for bipolar depressed (BD) patients have yielded mixed results. In this retrospective, naturalistic, observational study, we reviewed charts of 317 patients undergoing rTMS treatment between 1/2015-2/2018, yielding 283 unipolar depressed (UD) and 34 BD patients. All were treated with a figure-of-8 coil, with either high-frequency (HF) left-sided, sequential bilateral (HF left-sided and low-frequency right-sided), or mixed protocols (switched from unilateral to bilateral mid-course).  Outcomes were the Generalized Anxiety Disorder scale (GAD-7) and Patient Health Questionnaire (PHQ-9). Total number of treatments and initial PHQ-9 scores did not differ between groups. BD patients had greater PHQ-9 change by treatment conclusion than UD patients. GAD-7 changes showed no between-group differences overall. PHQ-9 changes differences between groups were only seen with unilateral treatment, not with bilateral or mixed protocols. Unilateral treatment resulted in 45% remission (9/20) for BD patients vs. 15% (24/160) for UD patients by treatment end. Response was seen in 80% (16/20) of the unilaterally-treated BD patients vs. 39% (62/160) in UD patients. Regression analyses within BD patients found that unilateral treatment, use of non-lithium mood stabilizers, male sex, and number of treatments predicted PHQ-9 improvement.