An Attempt to Increase the Rate and Magnitude of the Antidepressant Effect of Transcranial Magnetic Stimulation (TMS). A Pilot Study

Objective: An attempt to increase the rate and magnitude of the antidepressant effect of rTMS by providing fast frequency rTMS to the left prefrontal cortex (LPFC) followed by slow frequency TMS to the right (R)PFC at each treatment session. Method: Eighteen adult patients with major depressive episode (15 unipolar and 3 bipolar) were randomly assigned into two treatment groups. The control group received 30 active trains (2s duration) of 20Hz rTMS to the LPFC followed by 200 1Hz p1acebo stimuli to the RPFC. The experimental group received 25 active trains (2s duration) of 20Hz rTMS to the LPFC followed by 200 active 1Hz stimuli to the RPFC. Stimulation was at 100% of motor threshold (MT). All patients received ten treatments over two weeks. Measurements were made using the Hamilton Depression Rating Scale, 17 item version (HDRS) and a range of self rated visual analogue scales (VASs) at baseline and after five and ten treatments. Response was defined as 50% reduction in HDRS rating and remission was defined as achieving an HDRS score of 8 or less. Results: No significant differences were found between the groups overall (Pillai trace = 0.126, F (2,15) = 1.08, p = 0.37 power = 0.20). After ten treatments five of nine control group patients achieved response and all five had achieved remission, while six of nine experimental group patients achieved response and four of these achieved remission. These differences were not statistically significant. Both control and experimental TMS patients showed significant improvement in objective and subjective ratings of depression over the duration of treatment. Conclusions: Ten treatments of 25 trains of 20Hz rTMS to the LPFC followed by 200 1Hz rTMS to the RPFC were not clinically superior to the 10 treatments of 30 trains of 20Hz rTMS to the LPFC followed by 200 placebo 1Hz to the RPFC with respect to the rate and magnitude of the antidepressant effect.