Effectiveness of unilateral vs. bilateral rTMS treatment on suicidal ideation in patients with depression and comorbid anxiety

      Background: This study assessed suicidal ideation (SI) severity in 1001 patients (nmales = 321, Mage = 44.82 years, SDage = 15.93 years) primarily diagnosed with major depressive disorder (MDD) with a secondary diagnosis of generalized anxiety disorder (GAD) using CHRT risk subscale scores (CHRT-R) and PHQ-9 Item #9 scores (I#9) before and after a course of rTMS in a naturalistic, clinical setting.
      Methods: Patients received 30 to 36 rTMS treatments (M = 35.90, SD = .58) either bilaterally (right dorsolateral prefrontal cortex (dlPFC) at 1 Hz for 360 pulses, then left dlPFC stimulation at 20 Hz for 1200 pulses (n = 678)) or unilaterally (left dlPFC at 10 Hz for 3000 pulses (n = 323)). PHQ-9, GAD-7, and CHRT scores were obtained before and after the treatment course.
      Results: 47.75% of patients (nMDD = 1001) achieved MDD remission (≤4 on PHQ-9), 54.75% of patients (nGAD = 1001) achieved GAD remission (≤4 on GAD-7). Of the 40.8% of patients with SI (nSI = 408) prior to treatment, 299 (73.28%) achieved remission (I#9 score = 0) by the end of treatment. Reductions in suicidality were statistically significant with a moderate effect size, on both the I#9 (W = 4224, Cohen’s dpaired = .57, p < .001) and the CHRT-R subscale (W = 15622, dpaired = .52, p < .001). Comparing outcomes for unilateral vs. bilateral rTMS, there were no significant differences in the degree of improvement in suicidality on either the I#9 score or CHRT-R score (p > 0.05).
      Conclusions: Both unilateral and bilateral rTMS achieved significant reductions in suicidality, with moderate effect sizes overall. The two types of intervention each showed similar effectiveness against suicidality, without significant differences in outcome.
      Keywords: rTMS, MDD, GAD, Suicidal Ideation