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

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.

Automated summary

This retrospective study analyzed the medical records of 317 patients undergoing rTMS treatment and found that bipolar depressed (BD) patients had greater changes in PHQ-9 scores than unipolar depressed (UD) patients by treatment conclusion. There were no between-group differences in GAD-7 score changes. Unilateral treatment resulted in higher rates of remission and response for BD patients compared to UD patients.