Evaluating the Efficacy of Transcranial Magnetic Stimulation to Treat Major DepressionTuesday, May 25th, 2010
New data published in the Archives of General Psychiatry suggest that, in a small subset of depressed patients who have not responded to antidepressants, daily monotherapy with left prefrontal repetitive transcranial magnetic stimulation (rTMS) may be effective and well tolerated. However, there are still questions as to how long patients should be treated and the magnitude of clinical benefit.
A sample of 190 patients from four U.S. hospital clinics who have not previously responded to antidepressant therapy were randomized to either an active treatment group (n=92) or a sham treatment (n=98). On average, the group was moderately treatment resistant and had failed approximately 9 clinical attempts with medication. Active treatment included stimulation of the left prefrontal cortex with an electromagnetic coil for 37.5 minutes daily for 3 weeks. The sham treatment mimicked the sensory experience of stimulation using a similar coil and scalp electrodes but with the magnetic field blocked. Participants were not allowed to use antidepressant, antipsychotic, and anticonvulsant medications for 2 weeks before baseline assessment and for the duration of active treatment but were allowed limited use of sedatives, hypnotics or anxiolytics. The primary outcome measure was defined as a Hamilton Rating Scale for Depression (HAM-D) score of 3 or less, or two consecutive HAM-D scores less than 10.
In an intention-to-treat analysis, the study completion rates were 86% for the active treatment group and 90% for the sham group. Depression remitted in 14.1% of patients who received rTMS and 5.1% in those who received sham treatment (95% CI [confidence interval], 1.32 to 13.24; P=0.02). In a 3-week, open-label, follow-up phase of the study in which all patients received active therapy but remained masked to their original treatment arm, the remission rates rose to 30.2% in the originally active group and 29.6% in the original sham group. The treatment was relatively well tolerated, with no difference in adverse events between the two treatment arms.
The key strength of this study was the development of a blinding tool that simulated the rTMS treatment to maintain the blinding for patients, raters, and treaters. Although this study was independently supported by the National Institutes of Health, several of the researchers on the team have unpaid consulting ties to various companies involved in the manufacture of rTMS instrumentation.
- George MS, Lisanby SH, Avery D, et al. Daily left prefrontal transcranial magnetic stimulation therapy for major depressive disorder. Arch Gen Psychiatry. 2010;6(5):507-516. Abstract available at: http://archpsyc.ama-assn.org/cgi/content/abstract/67/5/507. Accessed May 25, 2010.