The neurobiological basis of therapeutic use of repetitive transcranial magnetic stimulation (rTMS) in psychiatric disorders

In recent years, the therapeutic properties of repetitive transcranial magnetic stimulation (rTMS) have been investigated for the treatment of various psychiatric disorders such as unipolar and bipolar disorders and schizophrenia. According to Faraday's low the induction of a magnetic field evokes intracerebral electric currents. This, in turn, influences neuronal networks in psychopathologically relevant brain regions thought to be dysfunctional in psychiatric disorders. In order to optimize rTMS for therapeutic use, however, it is indispensable to understand the neurobiological mechanisms involved. So far, the use of US in the treatment of psychiatric disorders can be recommended only in the context of scientific studies. There is compelling evidence resulting from basic science that rTMS can induce specific alterations in neuronal networks. In animal models, these changes are reflected by characteristic behavioural changes and decreases in the activity of the stress hormone system. In addition, regional changes in neurotronsmitter/neuromodulator release and in gene transcription could be demonstrated in relevant brain regions. Together, the mechanisms investigated so far ore, in part, reminiscent of those accompanying antidepressant drugs.