Alcoholism is a genetically complex disorder. That is, it is produced by an unknown number of genes that interact in an unknown fashion with one another and with an unknown variety of environmental factors. To dispense with the mystery, individuals who wish to identify their risk for developing alcoholism can undergo a noninvasive measure of brain electrical activity called P300 event-related potential (ERP), one of the few brain measures associated with risk for alcoholism. A study in the September issue of Alcoholism: Clinical & Experimental Research examines the variation in P300 amplitude in individuals with co-existing alcohol-use and anxiety disorders.
"We predicted," said Mary-Anne Enoch, a staff scientist in the Laboratory of Neurogenetics at the National Institute on Alcohol Abuse and Alcoholism and lead author of the study, "based on the results of previously published studies, that alcoholics would have low P300, anxiety disorder subjects would have high P300, but we could not predict which way alcoholics with anxiety disorders would go." Some of their findings were expected, while others were not.
"Even though our subjects had less severe forms of alcoholism and anxiety disorders, we nonetheless found that alcoholics had lower P300 amplitudes, and subjects with anxiety disorders had higher P300 amplitudes. When we looked at the subgroups, the results were much more dramatic. We found that it was the alcoholics with co-morbid anxiety disorders