Virtual Conference as a result of Hurricane Wilma of the 20th Annual Meeting of the Society for Research in Psychopathology (SRP), Miami, FL, October 25, 2005.
EEG Alpha as a Predictor of Response to an SSRI Antidepressant
J.P. Sedoruk1, C.E. Tenke1,3, J.W. Stewart2,3, P.J. McGrath2,3, G.E. Bruder1,3
1Department of Biopsychology, New York State Psychiatric Institute, NY, NY, USA
2Depression Evaluation Service, New York State Psychiatric Institute, NY, NY, USA
3Department of Psychiatry, Columbia University College of Physicians and Surgeons, NY, NY, USA
Abstract
The present study examined pretreatment differences in regional hemispheric activity among depressed patients who did or did not respond to an SSRI antidepressant and healthy controls. Resting EEG (eyes open and closed; nose reference) was recorded from 28 electrodes (plus eye channels) in 18 depressed patients (13 male; 20-56 years old; 12 treatment responders) when off medication and 18 healthy controls (13 male; 19-56 years old). Clinical response to 12 weeks of fluoxetine treatment was assessed using the CGI-I. Treatment responders had significantly greater alpha power
(less activity) when compared to either nonresponders or controls. There was also an overall group by hemisphere interaction, with nonresponders showing greater activity (less alpha) over right than left hemisphere, while responders tended to have the opposite asymmetry. The opposite direction of alpha asymmetry in treatment responders and nonresponders was particularly striking over parietal and occipital sites. Using median values for controls as the cutoff, both alpha asymmetry and amplitude at posterior sites were significantly predictive of clinical response to fluoxetine. The findings replicate our prior study (Bruder et al., 2001) and suggest the potential value of EEG measures of regional hemispheric asymmetry as predictors of therapeutic response to an SSRI antidepressant.
Support Contributed By: NIMH Grant MH36295
Key Words: depression, EEG, alpha, asymmetry, amplitude, prediction