Depression and alcoholism linked to one gene in African Americans

A gene variant involved in brain development is strongly associated with the risk of developing both major depression and alcoholism in African Americans, according to a new genome-wide association study (GWAS) by Yale and University of Pennsylvania researchers, published Oct. 25 in the journal JAMA Psychiatry.

The SEMA3A gene variant discovered in the analysis of entire genomes of more than 7800 subjects, had previously not been found in genetic studies of either alcoholism or depression individually. While researchers have long known people with either alcoholism or depression are at higher risk of having the other disorder, the study is one of the first to look for genetic basis of this co-morbidity.  

"The strength of the findings was unexpected—this was a very strong signal," said Joel Gelernter, the Foundations Fund Professor of Psychiatry, and professor of genetics and of neuroscience.

The specific association was in African American study subjects and—for reasons that are unclear—not in those of European ancestry, report the researchers.