Department of Clinical Neurophysiology, Addenbrooke's Hospital, Cambridge.
INTRODUCTION: Repetitive transcranial magnetic stimulation (rTMS) has been proposed as a possible alternative to electroconvulsive therapy for the treatment of selected patients with depression, bipolar affective disorder and schizophrenia. The aim of this study was to evaluate the evidence for the effectiveness of rTMS in mood disorders and schizophrenia. METHODS: Studies were identified using MEDLINE (1966 to January 2000), EMBASE/Excerpta Medica (1980 to January 2000), Biological Abstracts and Index to Scientific and Technical Proceedings. A number of biomedical and TMS related websites were also searched. We estimated the number needed to treat to show beneficial effect of rTMS when compared with the placebo controlled group. RESULTS: Seven controlled trials of rTMS depression were identified. Five of these were suitable for meta-analysis and show a beneficial effect of rTMS compared to placebo, with a number needed to treat of 2-3 with a 95 % confidence interval 1.6 to 4.0, total; 81 patients. A single trial of rTMS has also been performed in mania, which shows a beneficial effect of right hemisphere stimulation when compared with left hemisphere stimulation. A controlled trial in schizophrenia failed to show any benefit of rTMS. DISCUSSION: rTMS has demonstrable beneficial effects in depression. The extent and the duration of the anti-depressant effect of rTMS has yet to be defined. There now needs to be randomized controlled trials to compare rTMS directly with standardized electroconvulsive therapy in order to take this subject forward. With regard to the treatment of other mood disorders and schizophrenia, we are at an early stage in the assessment of further studies that are needed to examine any potential role for rTMS.