EEG asymmetry: Relationship to mood and risk for alcoholism in mission Indian youth

Background: Left frontal electroencephalogram (EEG) alpha dominance has bee n hypothesized to be related to depressed mood as well as aversive motivati on and emotion. However, few studies have prospectively evaluated electroen cephalogram asymmetry during development in high-risk adolescents and child ren. Methods: EEG alpha asymmetry was investigated in 134 Mission Indian childre n who were between 7 and 13 years of age. The relationships between electro encephalogram alpha asymmetry and age, gender, parental history of alcohol dependence, Native American heritage, and mood/approach behaviors were expl ored. Results: No significant relationship was found between frontal alpha asymme try and age, gender, or behavioral measures of depressed mood and/or approa ch behaviors. However, participants with greater than or equal to 50% Nativ e American heritage were significantly more likely to have greater electroe ncephalogram alpha power in the left frontal cortex than in the right. Conclusions: The present findings suggest that the hypothesized relationshi p between EEG alpha asymmetry and measures of depressed mood, aversive moti vation, and emotion may not be universal in all age or ethnic groups. Addit ionally, though the relationship between greater degrees of Native American heritage and alpha asymmetry are not as yet clear, we suggest it may be mo re related to substance abuse than depression in this population of Mission Indians. (C) 2001 Society of Biological Psychiatry.