For years, researchers have observed that alcohol consumption is associated with reduced brain volume and concluded that drinking can literally shrink the brain.
But new research turns that theory on its head, suggesting that reduced brain volume may represent a genetically-conferred predispositional risk factor for heavier alcohol consumption.
“Our results suggest that associations between alcohol consumption and reduced brain volume are attributable to shared genetic factors,” said senior author Ryan Bogdan, associate professor of psychological and brain sciences in Arts & Sciences and director of the Brain Lab at Washington University in St. Louis, where the research is based. “Lower brain volume in specific regions may predispose a person to greater alcohol consumption.
“The study is impressive because it uses a variety of approaches and data analysis techniques to reach findings that all converge on the same conclusion,” he said.
The study, recently published online in the journal Biological Psychiatry, is based on longitudinal and family data from three independent brain imaging studies – including the comparison of drinking behaviors in twin and non-twin siblings; longitudinal research within children who were never exposed to alcohol at baseline; and gene expression analyses using postmortem brain tissue.
“Our study provides convergent evidence that there are genetic factors that lead to both lower gray matter volumes and increased alcohol use,” said David Baranger, the study’s lead author and a former doctoral student in in Bogdan’s lab.
“These findings don’t discount the hypothesis that alcohol abuse may further reduce gray matter volumes, but it does suggest that brain volumes started out lower to begin with,” Baranger said. “As a result, brain volumes may also serve as useful biological markers for gene variations linked to increased vulnerability for alcohol consumption.”
Baranger, who is now a postdoctoral scholar at the University of Pittsburgh, led the research project, which included other Arts & Sciences psychology graduate students and faculty from Washington University School of Medicine in St. Louis; Duke University; and the Medical University of South Carolina.