Effect of repetitive transcranial magnetic stimulation on serum brain derived neurotrophic factor in drug resistant depressed patients

Background: Depression has been associated with low brain-derived neurotrophic factor (BDNF) serum levels, while antidepressant drugs appear to mend this alteration. The purpose of this study was to assess BDNF serum levels in drug resistant depressed patients before and after repetitive Transcranial Magnetic Stimulation (rTMS) antidepressant treatment. Methods: BDNF levels were measured in serum of 16 resistant depressed patients using the ELISA technique. Results: BDNF baseline levels showed a negative correlation with illness severity measured by HDRS scores (R=-0.517,p=0.04) and a significant increase of serum BDNF was found after rTMS treatment (t=-2.549, df= 15, p=0.022). Conclusions: Our findings support the relationship between decreased serum BDNF and depression symptomatology and suggest a normalizing effect of rTMS antidepressant treatment. Further replications in larger samples will help to clarify the relevance of this preliminary data in the rTMS mechanism of action. (c) 2005 Elsevier B.V. All rights reserved.