EEG asymmetry: relationship to mood and risk for alcoholism in Mission Indian youth

Background: Left frontal electroencephalogram (EEG) alpha dominance has been hypothesized to be related to depressed mood as well as aversive motivation and emotion. However, few studies have prospectively evaluated electroencephalogram asymmetry during development in high-risk adolescents and children. Methods: EEG alpha asymmetry was investigated in 134 Mission Indian children who were between 7 and 13 years of age. The relationships between electroencephalogram alpha asymmetry and age, gender, parental history of alcohol dependence, Native American heritage, and mood/approach behaviors were explored. Results: No significant relationship was found between frontal alpha asymmetry and age, gender, or behavioral measures of depressed mood and/or approach behaviors. However, participants with ≥50% Native American heritage were significantly more likely to have greater electroencephalogram alpha power in the left frontal cortex than in the right. Conclusions: The present findings suggest that the hypothesized relationship between EEG alpha asymmetry and measures of depressed mood, aversive motivation, and emotion may not be universal in all age or ethnic groups. Additionally, though the relationship between greater degrees of Native American heritage and alpha asymmetry are not as yet clear, we suggest it may be more related to substance abuse than depression in this population of Mission Indians.