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

BackgroundDespite 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.MethodsWe 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.ResultsResponders (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).ConclusionLow 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.