Background: Electroencephalographic (EEG) measures of hemispheric asymmetry in anterior brain activity have been related to a variety of indices of psychopathology and emotionality. However, little is known about patterns of frontal asymmetry in alcohol-dependent (AD) samples. It is also unclear whether psychiatric comorbidity in AD subjects accounts for additional variance in frontal asymmetry, beyond a diagnosis of AD alone.
Methods: We compared 193 AD subjects with 108 control subjects on resting brain activity in anterior and posterior regions, as indexed by asymmetries in alpha band power in the left and right hemispheres. Within the AD group alone, we examined whether comorbid major depressive disorder (MDD) or antisocial personality disorder (ASPD) had effects on regional asymmetry.
Results: Compared with control subjects, AD subjects exhibited lower left, relative to right, cortical activation in anterior regions. Evidence that comorbidity in AD subjects accounted for further variance in EEG asymmetry was mixed; AD subjects with comorbid ASPD were not significantly different from those without ASPD, while AD subjects with a lifetime history of MDD showed less asymmetry in anterior regions than those without MDD.
Conclusions: Our findings indicate that AD subjects exhibit a pattern of frontal asymmetry similar to that found in other psychiatric groups. Results examining the effects of comorbidity in AD on EEG asymmetry were inconclusive. The implications of our findings for future work are described.