Repetitive transcranial magnetic stimulation (rTMS) is widely investigated and has been proved to have positive effect on treatment-resistant depression. The Food and Drug Administration has authorized rTMS to be used in this indication in several countries. However, patients do not all benefit equally from rTMS.

We therefore sought to identify the clinical and demographic factors associated with response and remission after rTMS in chronic and resistant depression.

76 patients suffering from unipolar or bipolar depressive episode received 10 high frequency rTMS sessions, one per day, over the left dorsolateral prefrontal cortex (10 Hz, 95% Motor Threshold, 5s on, 25s off). All patients were antidepressant-free or taking a stable antidepressant drug for at least one month.

Nearly half of patients had responded to the treatment (47.4%) and 16 went into remission (21.1%) by the end of the study (immediately after the last rTMS session). Morover, as shown by using simple and multiple logistic regressions, the age at which the first episode occurred and the initial level of state anxiety were associated with a higher response rate. A hyperthymic temperament and a greater trait anxiety were shown to be associated to a higher remission rate.

The results obtained suggest that unipolar and bipolar patients may react differently to rTMS. These two subgroups of affective disorders could benefit from specific, separate paradigms.