REGIONAL BRAIN ASYMMETRIES IN MAJOR DEPRESSION WITH OR WITHOUT AN ANXIETY DISORDER - A QUANTITATIVE ELECTROENCEPHALOGRAPHIC STUDY

Studies of brain activity in affective disorders need to distinguish b etween effects of depression and anxiety because of the substantial co morbidity of these disorders, Based on a model of asymmetric hemispher ic activity in depression and anxiety, it was predicted that anxious a nd nonanxious depressed patients would differ on electroencephalograph ic (EEG) measures of parietotemporal activity. Resting EEG (eyes close d and eyes open) was recorded from 44 unmedicated outpatients having a unipolar major depressive disorder (19 with and 25 without an anxiety disorder), and 26 normal controls using 30 scalp electrodes (13 homol ogous pairs over the two hemispheres and four midline sites). As predi cted depressed patients with an anxiety disorder differed from those w ithout an anxiety disorder in alpha asymmetry. Nonanxious depressed pa tients showed an alpha asymmetry indicative of less activation over ri ght than left posterior sites, whereas anxious depressed patients show ed evidence of greater activation over right than left anterior and po sterior sites. The findings are discussed in terms of a model in which specific symptom features of depression and anxiety are related to di fferent patterns of regional brain activity. (C) 1997 Society of Biolo gical Psychiatry.