Prognostic Factors in Major Depressive Disorder: Comparing Responders and Non-Responders to Repetitive Transcranial Magnetic Stimulation (rTMS), a Naturalistic Retrospective Chart Review

SOURCE: Psychiatry & Clinical Neurosciences. 77(1):38-47, 2023 Jan.

AUTHORS: Abo Aoun M; Meek BP; Clair L; Wikstrom S; Prasad B; Modirrousta M

AIM: Repetitive transcranial magnetic stimulation (rTMS) is widely utilized as an effective treatment for major depressive disorder (MDD) with varying response rates. Factors associated with better treatment outcome remain scarce. This naturalistic retrospective chart review hopes to shed light on easily obtainable and measurable predictive factors for patients referred to rTMS.

METHODS: Protocol parameters, medication, rated scales, rTMS protocols, and treatment outcomes were reviewed for 196 patients with MDD who received rTMS at Saint Boniface Hospital between 2013 and 2019. Logistic regression and marginal effects were used to assess the different predictor variables for response (50% reduction or more on the Hamilton Depression Rating Scale (Ham-D)) and remission (Ham-D of <=7 by the last session).

RESULTS: HamD at 10 sessions was predictive of remission, and Sheehan Disability Scale (SDS) at 10 sessions was predictive of response to rTMS. Ham-D, SDS, and Beck Anxiety Inventory were predictive of remission and response by Beck Anxiety Inventory 20 sessions. High frequency rTMS had a similar response and remission rate to low frequency, but higher response rate to intermittent Theta Burst Stimulation with no difference in remission rate. Positive predictive factors of response were lower age and bupropion use. Negative predictive factors were antipsychotics, anticonvulsants, or benzodiazepine use. For remission, antipsychotics or anticonvulsants use were negative predictors; bupropion use and higher resting motor threshold were positive predictors. Severity of depression as measured by baseline HamD was not associated with different probabilities of treatment success.