Augmentative repetitive Transcranial Magnetic Stimulation (rTMS) in the acute treatment of poor responder depressed patients: a comparison study between high and low frequency stimulation.

BACKGROUND

While the efficacy of repetitive transcranial magnetic stimulation (rTMS) in Major Depressive Disorder (MDD) is well established, the debate is still open in relation to bipolar depression and to a possible different effectiveness of high vs. low stimulation. The present study was aimed to assess and compare the efficacy and tolerability of different protocols of augmentative rTMS in a sample of patients with current Major Depressive Episode (MDE), poor drug response/treatment resistance and a diagnosis of MDD or bipolar disorder.

METHODS

Thirty-three patients were recruited in a 4-week, blind-rater, rTMS trial and randomised to the following three groups of stimulation: (1) (n=10) right dorsolateral prefrontal cortex (DLPFC) 1 HZ, 110% of the motor threshold (MT), 420 stimuli/day; (2) (n=10) right DLPFC, 1Hz, 110% MT, 900 stimuli/day; (3) (n=13) left DLPFC, 10Hz, 80% MT, 750 stimuli/day.

RESULTS

Twenty-nine patients completed the treatment, showing a significant reduction of primary outcome measures (HAM-D, MADRS and CGI-S total scores: t=8.1, P<0.001; t=8.6, P<0.001; t=4.6, P<0.001 respectively). No significant differences in terms of efficacy and tolerability were found between high vs. low frequency and between unipolar and bipolar patients. Side effects were reported by 21% of the sample. One of the 4 dropouts was caused by a hypomanic switch.

CONCLUSIONS

Augmentative rTMS appeared to be effective and well tolerated for the acute treatment of unipolar and bipolar depression with features of poor drug response/treatment resistance, showing a comparable effectiveness profile between protocols of high and low frequency stimulation.