The impact of repetitive transcranial magnetic stimulation on pituitary hormone levels and cortisol in healthy subjects

Background: Repetitive transcranial magnetic stimulation (rTMS) is a new th erapeutic tool in the treatment of affective disorders but only few studies on its safety exist. We aimed to determine the impact of rTMS on (neuro)en docrinological serum levels by a placebo-controlled cross-over study. Metho ds: 23 healthy subjects were stimulated by rTMS in a typical paradigm used in the treatment of depression (coil placed over left dorsolateral prefront al cortex, 10 and 20 Hz stimulation). Placebo, infrathreshold, and suprathr eshold stimulation were applied in random order. The serum levels of cortis ol, prolactin, FSH, and TSH were measured before and after stimulation. Res ults: After infrathreshold stimulation, cortisol and TSH serum levels decre ased mildly but significantly. All other stimulations had no significant im pact on hormone levels. In female, but not in male, subjects placebo stimul ation yielded a significant increase of prolactin. Conclusions: rTMS as app lied for the treatment of depression leads to only very mild and safe chang es of hormones. These changes, in particular the decrease of cortisol level s, might explain in part the efficacy of rTMS. (C) 2001 Elsevier Science BY . All rights reserved.