Clinical and demographic predictors of response to rTMS treatment in unipolar and bipolar depressive disorders.

Objective: Previous studies investigated predictors of repetitive transcranial magnetic stimulation (rTMS) response in depressive disorders but there is still limited knowledge about clinical predictors. Moreover, predictors of rTMS response in bipolar depression (BDD) are less studied than unipolar depression (UDD).

Methods: We performed a binary logistic regression analysis in 248 patients with depressive disorders (unipolar N=102, bipolar N=146) who received 20 sessions of DLPFC rTMS (High-frequency rTMS, low-frequency rTMS, bilateral rTMS) to investigate significant clinical and demographic predictors of rTMS response. We also investigated effects of depression type, response (yes, no) and time on reducing somatic and cognitive-affective symptoms of patients.

Results: Depression type (unipolar vs. bipolar) did not have a significant effect on rTMS response. 45% of all patients, 51.5% of UDD patients and 41% of BDD patients, responded to rTMS treatment. Age was the only significant demographic predictor of treatment response in all patients. Cognitive-affective symptoms, compared to somatic symptoms were significant predictors for treatment response to rTMS. Common and unique clinical predictor for UDD and BDD were identified.

Conclusions: Younger patients and those with cognitive-affective rather than somatic symptoms benefit more from DLPFC rTMS treatment. rTMS is effective in UDD and BDD patients. Patients should be selected based on clinical and demographic profile.

Significance: Findings are based on the largest thus far reported sample of patients with depressive disorders that received DLPFC rTMS.