Electroencephalographic alpha measures predict therapeutic response to a selective serotonin reuptake inhibitor antidepressant: pre- and post-treatment findings.
BACKGROUND
There is growing evidence that individual differences among depressed patients on electrophysiologic (EEG), neuroimaging, and neurocognitive measures are predictive of therapeutic response to antidepressant drugs. This study replicates prior findings of pretreatment differences between selective serotonin reuptake inhibitor (SSRI) responders and nonresponders in EEG alpha power or asymmetry and examines whether these differences normalize or are stable after treatment.


METHODS
Resting EEG (eyes open and closed) was recorded from 28 electrodes (nose reference) in 18 depressed patients when off medication and at the end of 12 weeks of fluoxetine treatment. Clinical response was assessed by an independent rater with the Clinical Global Impression Improvement scale. The EEG data were also obtained for 18 healthy adults matched to patients in gender and age.


RESULTS
Treatment responders had greater alpha power compared with nonresponders and healthy control subjects, with largest differences at occipital sites where alpha was largest. There were also differences in alpha asymmetry between responders and nonresponders at occipital sites. Responders showed greater alpha (less activity) over right than left hemisphere, whereas nonresponders tended to show the opposite asymmetry. Neither alpha power nor asymmetry changed after treatment, and test-retest correlations were high, particularly for alpha power. Alpha power and asymmetry showed reasonable positive predictive value but less negative predictive value.


CONCLUSIONS
The findings confirm reports of alpha differences between antidepressant responders and nonresponders and raise hopes for developing EEG tests for selecting effective treatments for patients. The stability of alpha power and asymmetry differences between SSRI responders and nonresponders after treatment suggests that they represent state-independent characteristics.
Bruder
Gerard E
GE
Department of Psychiatry, College of Physicians and Surgeons of Columbia University, New York, New York, USA. bruderg@pi.cpmc.columbia.edu
Sedoruk
James P
JP
Stewart
Jonathan W
JW
McGrath
Patrick J
PJ
Quitkin
Frederic M
FM
Tenke
Craig E
CE
D000328:Adult; D000513:Alpha Rhythm; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000187:drug effects / Q000503:physiopathology; D003866:Depressive Disorder / Q000188:drug therapy* / Q000503:physiopathology; D004292:Dominance, Cerebral / Q000187:drug effects / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D004569:Electroencephalography / Q000187:drug effects*; D005260:Female; D005473:Fluoxetine / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010555:Personality Inventory; D011237:Predictive Value of Tests; D011379:Prognosis; D017367:Selective Serotonin Reuptake Inhibitors / Q000627:therapeutic use*; D016037:Single-Blind Method; D016896:Treatment Outcome
D005473:Fluoxetine; D017367:Selective Serotonin Reuptake Inhibitors