Personality Trait Predictive Utility and Stability in Transcranial Magnetic Stimulation (rTMS) for Major Depression: Dissociation of Neuroticism and Self-Criticism.

Background: Cost-efficient and non-invasive predictors of antidepressant response to repetitive transcranial magnetic stimulation (rTMS) are required. The personality vulnerabilities-neuroticism and self-criticism-are associated with antidepressant outcomes in other modalities; however, self-criticism has not been examined in response to rTMS, and the literature on neuroticism and rTMS is inconsistent. Methods: This naturalistic, 4-week study involved daily dorsolateral prefrontal cortex (DLFPC) rTMS for major depression (15 unipolar, 2 bipolar). Participants completed the Big Five Inventory (neuroticism) and the Depressive Experiences Questionnaire (self-criticism) at baseline and at the end of treatment. Changes in depressive symptoms, as rated by the clinician, were quantified using the 21-item Hamilton Depression Rating Scale. Given the inconsistencies in data regarding the stability of neuroticism in patients receiving rTMS, we performed a systematic review and quantitative meta-analysis of trials examining rTMS and neuroticism. Results: rTMS significantly improved depressive symptoms, and this was predicted by higher levels of self-criticism but not neuroticism. Self-criticism was stable over the 4 weeks of rTMS; however, neuroticism decreased, and this was not related to decreases in depressive symptoms. Our quantitative meta-analysis of 4 rTMS trials in major depression (n = 52 patients) revealed decreases in neuroticism, with a moderate effect size. Limitations: Our results are limited by a small sample size, and the absence of a sham-rTMS group. Our meta-analysis included only 4 trials. Conclusion: Highly self-critical patients appear to benefit more from rTMS than less self-critical patients. Neuroticism, a conceptually similar but distinct personality domain, does not appear to predict antidepressant response, yet this vulnerability factor for depression decreases after rTMS.