Electrophysiological responses to affective stimuli in southwest California Indians: Relationship to alcohol dependence

Objective: Native Americans have some of the highest rates of alcohol abuse and dependence, yet potential risk factors associated with the problem drinking seen in some tribes remain relatively unknown. The present investigation evaluated associations between the P350 and P450 components of the event-related potential (ERP) elicited by affective stimuli and potential vulnerability factors associated with risk of alcohol dependence in Southwest California (SWC) Indian adults. Method: Data from 517 Native American SWC Indian adults between the ages of 18 and 70 were used in the analyses. ERPs were collected using a task that required discrimination among faces with neutral, sad, and happy facial expressions. Results: P450 amplitudes were significantly reduced in participants who met lifetime Diagnostic and Statistical Manual of Mental Disorders, Third Edition, Revised, criteria for alcohol dependence in centroparietal leads. In contrast, participants who met personal lifetime criteria for affective disorder were found to have higher P350 and P450 amplitudes in frontal leads. Neither P350 nor P450 component amplitudes were significantly altered based on a family history of alcohol dependence, a personal history of antisocial personality disorder/conduct disorder, or the presence of drug dependence other than alcohol. Conclusions: These findings suggest, in this select population, that P450 amplitudes are selectively affected by both alcohol dependence and affective disorder. However, reductions in P450 amplitude were restricted to those participants with alcohol dependence, confirming that it may be an important putative endophenotype for genetic studies of that disorder in this high-risk population.