The influence of personality on the effect of iTBS on cortisol secretion in stressed healthy females

Abstract

It has been proposed that personality dimensions may be used to predict the response to repetitive Transcranial Magnetic Stimulation (rTMS) at the individual level. However, the underlying physiological mechanisms as to how personality may influence the effect of rTMS remains to be clarified. In this sham-controlled proof-of-concept study, we investigated whether personality features (assessed using the Temperament and Character Inventory) influence the effect of intermittent theta burst stimulation (iTBS) on the regulation of the hypothalamic-pituitary-adrenal axis. Thirty-eight healthy females received two sessions of iTBS over the left dorsolateral prefrontal cortex (DLPFC) after being stressed by the Trier Social Stress Test. Mood and salivary cortisol were assessed throughout the experimental protocol. We found overall no differences in the total cortisol secretion and the cortisol response to stress between the active and sham iTBS sessions. When taking into account personality features, our results show that when two sessions of iTBS over the left DLPFC are applied in stressed healthy females, a reduction in cortisol secretion is observed in individuals scoring higher in Cooperativeness. Our observations shed further light on the understanding of the influence of personality characteristics in the clinical outcome of rTMS in stress-related disorders.