Effects of smoking status and MADRS retardation factor on response to low frequency repetitive transcranial magnetic stimulation for depression

Abstract : Abstract Background Despite growing evidence supporting the clinical interest of repetitive transcranial magnetic stimulation (rTMS) in treatment-resistant depression (TRD), little is known regarding the effects of clinical and sociodemographic factors on the clinical outcome in patients. Methods We retrospectively investigated the effects of clinical (using the 3-factor model of the Montgomery-Åsberg depression rating scale [MADRS] encompassing dysphoria, retardation and vegetative symptoms) and sociodemographic characteristics of participants on clinical outcome in a sample of 54 TRD patients receiving low frequency rTMS (1 Hz, 360 pulses) applied over the right dorsolateral prefrontal cortex combined with sham venlafaxine. Results Responders ( n = 29) displayed lower retardation baseline scores (13.6 ± 2.9) than non-responders (15.6 ± 2.9; n = 25; P = 0.02). We also observed a significant difference between the numbers of ex-smokers in responders and non-responders groups; all ex-smokers ( n = 8) were responders to rTMS ( P = 0.005). Conclusion Low MADRS retardation factor and ex-smoker status is highly prevalent in responders to low frequency rTMS. Further studies are needed to investigate the predictive value of these factors.