Little is known about the post-acute effects of repetitive transcranial magnetic stimulation (rTMS) in patients with major depression. The present study focused on the 6-month follow-up of a sample of patients with major depression, after the completion of an acute 4 weeks rTMS trial, with the aim of evaluating response (in terms of sustained and late response) and relapse rates.

Following the completion of an acute trial of rTMS (T0-T4), 31 drug-resistant depressed patients (bipolar or unipolar) entered a naturalistic follow-up period of 6 months, with three timepoints (T5, T6, and T7) during which they were assessed with the Hamilton Depression Rating Scale and the Young Mania Rating Scale.

Results showed that in the 6 months following an acute transcranial magnetic stimulation (TMS) trial, a higher rate of late responders was observed among previously acute TMS nonresponders (63.64%, 7 out of 11) compared to the rate of relapse among those who had acutely responded to TMS (10%, 2 out of 20). In addition, an overall high rate of maintained response (90%) was observed.

Present findings seem to support the possibility of obtaining a clinical response also after the end of an acute TMS trial in patients with major depression. The concomitant low rate of relapse observed at the end of follow-up along with a high rate of maintained response provides further support to the post-acute efficacy of TMS. Nonetheless, further controlled studies, with larger samples and longer follow-up observation, are needed to confirm the reported results.