Depuis 10 ans, l’évaluation de l’intérêt thérapeutique de la stimulation magnétique transcrânienne répétée (rTMS) fait l’objet d’un intérêt croissant. Basée sur le principe d’induction découvert par Michael Faraday en 1831, la rTMS pourrait constituer une méthode thérapeutique antidépressive et, peut-être, une alternative à l’électroconvulsivothérapie (ECT). Afin de faire le point des connaissances dans ce domaine, nous avons analysé les principaux travaux réalisésà ce jour au travers de leur diversité méthodologique par l’intermédiaire d’une consultation de la banque de données informatisée Medline et d’une base de données disponible en ligne (ISTS), complétée d’une recherche manuelle ; nous avons retenu 66 études qui font l’objet de cette revue. Malgré l’hétérogénéité de ces publications en termes de méthodologie et de paramètres de traitements, les propriétés antidépressives de la rTMS semblent se dessiner (37 % de sujets répondeurs vs 20 % dans les groupes contrôles sur 30 études analysables) et ceci ouvre des perspectives intéressantes, dans le traitement des dépressions résistantes et peut-être en tant que potentialisateur des antidépresseurs dans les autres formes de dépression. Cependant, un grand nombre d’inconnues subsistent (méthodologie du traitement et indications privilégiées), ce qui justifie le développement de travaux d’évaluation structurés sur de grands échantillons.

Introduction. In 1985, Barker et al. showed that it was possible to stimulate both nerves and brain using external magnetic stimulation without significant pain. During the past 10 years, therapeutic effects of repeated Transcranial Magnetic Stimulation (rTMS) have been widely studied in psychiatry and its efficacy has been demonstrated in the treatment of major depressive disorders, particularly as an alternative to electroconvulsivotherapy (ECT). Facing the large range of studies, we found necessary to propose an up-to-date review in French of the methodological and therapeutic variations among them. Method. Based on an exhaustive consultation of Medline data and the The Avery-George-Holtzheimer Database of rTMS Depression ­Studies, supplemented by a manual research, only works evaluating the therapeutic efficacy of rTMS on depressive symptoms were retained, excluding all studies exclusively investigating the stimulation parameters or the tolerance as well as case reports. Results. Out the 66 available reports we retained 30 studies. After a description of the main results of these 30 studies, several elements of the 66 will be discussed. Open studies demonstrated that short courses rTMS (5 to 10 sessions) produced a decrease in the mean Hamilton Depression Ratting Scale (HDRS) scores, although significant remission of depression in individuals was rare. Most authors had used high frequency rTMS applied to the left Dorso Lateral Prefrontal Cortex (left DLPFC). However, low frequency rTMS applied to the right DLPFC was also followed by significant reduction of HDRS scores. Parallel arm, double blind versus placebo studies are designed to clarify the therapeutic efficacy of rTMS therapy but conclude in contradicting results. Literature data globally confirms a greater efficacy of rTMS compared to placebo (37 % responders in the active group vs 20 % in the sham). This efficacy could in fact be even greater because the sham procedure is disputable in most studies. Indeed, positioning rTMS coil at 45 or 90 from the scalp may not represent an accurate sham procedure and the use of real sham coil is to be recommended. Only one study has suggested that associating rTMS and ECT could decrease the number of general anesthesia required. Therapeutic efficacy has been shown by either inhibiting the right DLPFC or by stimulating the left DLPFC, although some patients exhibit paradoxical responses. High frequency rTMS (> 5 Hz) increases cortical excitability and metabolism, while low-frequency rTMS stimulation ( 1 Hz) has the opposite effect. Other parameters are : relevant : intensity (from 80 to 110 % of motor threshold), total number of stimulations (from 120 to 2 000) and total number of rTMS sessions (from 5 to 20). As suggested in most recent studies, higher-intensity pulses, higher number of stimulation or longer treatment courses may be more effective. Greater responsiveness to rTMS may be predicted by several patients’ factors, including the absence of psychosis, younger age and previous response to rTMS therapy. Discussion. Conclusions on these factors and others, such as the importance of anatomically accurate coil placement and the distance from the coil to the brain, await further investigation. Despite heterogeneity of these reports according to methodology and treatment parameters, the antidepressive properties of rTMS now appear obvious, opening interesting prospects, in particular in the treatment of pharmacoresistant major depressive patients and, we hope, administered as adjuvant therapy in non-resistant depression. Conclusion. Thus, many questions remain unanswered concerning the optimal stimulation parameters, pri­vileged indications and maintenance sessions. This justifies the development of structured evaluation trials on larger samples.