Electroencephalographic Measures of Regional Hemispheric Activity in Offspring at Risk for Depressive Disorders

Gerard E. Bruder^1,2, Craig E. Tenke^1,2, Virginia Warner³, Yoko Nomura¹, Christian Grillon⁴, Jeffrey Hille⁵, Paul Leite², Myrna M. Weissman^1,3

¹Department of Psychiatry, College of Physicians and Surgeons of Columbia University, USA; ²Department of Biopsychology, New York State Psychiatric Institute, New York, USA; ³Department of Clinical and Genetic Epidemiology, New York State Psychiatric Institute, New York, USA; ⁴Mood and Anxiety Disorders Research Program, National Institute of Mental Health, Bethesda, Maryland; ⁵Department of Psychiatry, Yale University School of Medicine, New Haven, Connecticut, USA

Received 10 March 2004; Revised 3 November 2004; accepted 9 November 2004. 

Abstract

Background: Electroencephalographic (EEG) studies have found abnormal regional hemispheric asymmetries in depressive disorders, which have been hypothesized to be vulnerability markers for depression. In a longitudinal high-risk study, resting EEG was measured in primarily adult offspring of depressed or nondepressed probands. Methods: Electroencephalograms from12 homologous sites over each hemisphere (digitally linked-ears reference) were analyzed in right-handed offspring for whom both parents (n = 18), one parent (n = 40), or neither parent (n = 29) had a major depressive disorder (MDD). Results: Offspring with both parents having MDD showed greater alpha asymmetry at medial sites, with relatively less activity (more alpha) over right central and parietal regions, compared with offspring having one or no parent with MDD. Relatively less left frontal activity at lateral sites was associated with lifetime MDD in offspring but not with parental MDD. Offspring with both parents having a MDD also showed markedly greater anterior-to- posterior increase in alpha with eyes closed compared with those with one or no parent with a MDD. Conclusions: Alpha asymmetry indicative of right parietotemporal hypoactivity, previously reported for depressed adolescents and adults, and heightened anterior-to-posterior gradient of alpha are present in high-risk offspring having parents concordant for MDD.

Key Words: Alpha power, EEG, hemispheric asymmetry, high risk, major depressive disorder