[Affective disorders and repetitive transcranial magnetic stimulation: Therapeutic innovations]

Depression is the most common psychiatric disorder with a particularly important disability due to its evolution to chronicity and treatment-resistance. In the same way, the outcome of bipolar disorder is similar. Only 75% subjects remain remitted in the year following the onset of mood episode and depressive episode leads to worth responsiveness than patients in phase hypo/manic. Thus, treating mood episodes and fighting against resistant and residual symptoms or chronicity of the disorders constitute major clinical issues and economic challenges. They have generated great interest in finding new non-pharmacological approaches such as repetitive transcranial magnetic stimulation (rTMS). TMS is a non-invasive means of focal brain stimulation, rapidly fluctuating magnetic fields. Given the hypothesis that the right and left sides of the dorsolateral prefrontal cortex have opposing effects in mood control, high-frequency rTMS activates the left side and low-frequency to inhibit the right side in the treatment of depression. A literature review was conducted to study the efficacy of rTMS in the treatment of unipolar and bipolar depression, acute mania and long-term maintenance therapy. During the last decade, numerous studies including several meta-analyses have indicated the efficacy of rTMS in acute treatment of major depressive disorder. Overall, rTMS seems to be effective in the treatment of bipolar depression but further trials with larger cohorts should determine optimal parameters of stimulation. There are also few studies about rTMS in the treatment of acute mania. Protocols are reversed than in the treatment of depression. Results are promising but confounded by the presence of concurrent medications. Finally, the literature on the use of maintenance rTMS in the prevention of depressive relapse or as a mood stabiliser is limited. Nevertheless it demonstrates the importance of developing maintenance protocols to maintain the clinical improvement achieved at the end of the acute treatment. New techniques to improve the effectiveness of rTMS are already appearing.