Repetitive Transcranial Magnetic Stimulation for Treatment Resistant Depression: How patient characteristics and elements of treatment impact post-treatment outcomes

Introduction: The present study assessed the effectiveness of repetitive Transcranial Magnetic Stimulation (rTMS) in reducing depressive symptoms in patients with treatment-resistant depression. Methods and materials: A retrospective study conducted at an academic rTMS outpatient clinic. Data were collected from adult patients (≥ 18 years) with treatment-resistant, nonpsychotic unipolar depression. The Montgomery-Asberg Depression Rating Scale (MADRS) and Patient Health Questionnaire (PHQ-9) were administered at the initiation of treatment, at midpoint, and at completion. The Area Deprivation Index (ADI) was calculated to measure neighborhood disadvantage. Independent and paired t- tests were performed to assess the change in MADRS and PHQ-9 scores, for ages of less than or 65 and greater for baseline scores. Participants were assessed at the end of treatment as either full remission, partial response, or lack of response. The effectiveness of rTMS was analyzed with a multivariable general linear model (GLM) fitted to compare change in depression severity, while controlling for confounders. Results Sixty patients were included. Forty-five (75%) of the participants completed the 36 or more sessions of rTMS treatment. The end-of-treatment MADRS and PHQ-9 scores were statistically significantly different from the pre-treament scores ( P   < 0.001 ). The effect sizes were ( d  = 1.70 and 1.37), respectively. Regression modeling showed age, insurance status, Body Mass Index (BMI), number of sessions and duration of treatment were statistically significant. The MADRS demonstrated better model quality to discriminate good from poor responders than the PHQ-9. Conclusions The rTMS treatment was shown to be an effective modality for treatment-resistant depression. The analysis found that patient characteristics and treatment factors were predictive of the patient response. Future studies should investigate the link between overall functioning, health-related social needs and rTMS response.