No benefit derived from repetitive transcranial magnetic stimulation in depression: a prospective, single centre, randomised, double blind, sham controlled "add on" trial.

Repetitive transcranial magnetic stimulation (rTMS) has been reported to demonstrate slight effects in the treatment of depression. Hence, a novel bilateral versus unilateral and sham stimulation design was applied to further assess rTMS' antidepressant effects. Forty one medication free patients with major depression, admitted to a psychiatric unit specialising in affective disorders, were consecutively randomised into 3 groups. Group A1 (n = 12) received unilateral active stimulation consisting of high frequency (hf) rTMS over the left dorsolateral prefrontal cortex (LDLPC) and subsequent sham low frequency (lf) rTMS over the right dorsolateral prefrontal cortex (RDLPC). Group A2 (n = 13) received simultaneous bilateral active stimulation consisting of hf-rTMS over the LDLPC and lf-rTMS over the RDLPC. Group C (n = 13) received bilateral sham stimulation. Stimulation was performed on 10 consecutive workdays. All patients received antidepressant medication on the first day of stimulation, which was continued during and after the stimulation period. As no significant difference in antidepressant outcome between group A1 and A2 was found, the two groups were pooled. The time course of the outcome variables Hamilton depression rating scale (HDRS(21)) and Beck depression inventory (days 0, 7, 14, 28) by repeated measures analysis of variance revealed no significant group differences (in terms of a group by time interaction), whereas there was a significant effect of time on all three outcome variables in all groups. The results suggest that rTMS as an "add on" strategy, applied in a unilateral and a bilateral stimulation paradigm, does not exert an additional antidepressant effect.