INDIANAPOLIS, Sept. 3 (UPI) -- U.S. researchers have linked craving drink after smelling alcohol to a gene variation.
David Kareken of the Indiana University School of Medicine in Indianapolis and Edith Sullivan of California's Stanford University School of Medicine suggested genetics affect sensitivity to alcohol odor.
The study, published in Alcoholism: Clinical & Experimental Research, found the brains of homozygous GABRA2 gene carriers -- that is, participants with a double "dose" of this gene -- showed greater activity in regions of the brain's reward evaluation system, including the medial frontal cortex.
"By contrast, heterozygous GABRA2 carriers -- that is, participants with only a single dose of the gene -- activated a different component of the brain's reward system," Sullivan says in a statement.
Kareken, Sullivan and colleagues used functional magnetic resonance imaging to map brain responses in 36 participants --13 homozygous GABRA2 carriers and 23 heterozygous GABRA2 carriers.
"Alcoholism is a very complex disease that involves both genetics and the environment and it is highly unlikely that we will ever discover 'the gene' that controls who will or will not become alcoholic," said Kareken. "However, this study adds to our understanding of how certain genes might influence how strongly the brain's reward system responds to the sights and smells that motivate us to use, or over-use, the things that make us feel good."