The research team, headed by Shirley Y. Hill, professor of psychiatry, psychology, and human genetics at Pitt’s School of Medicine, studied adolescents who averaged 17 years of age from families with multigenerational alcohol dependence to see if they had morphological changes in their brains that could make them susceptible to alcohol abuse. Through brain imaging, Hill found changes in the amygdala, a walnut-sized structure in the brain that helps control basic emotions. Children from families with a history of abuse had reduced right amygdala volume compared with children from families with no abuse.

“The effect on the amygdala is significant because the amygdala is part of an important reward circuit that has been implicated in addictive behavior including cocaine use, gambling, and now, familial alcohol dependence. This circuit is one of the fundamental components of the brain’s reward systems and appears to be important in the reinforcing actions of repeated drug and alcohol abuse,” explained Hill.

Why the right amygdala in particular is affected is not known, but perhaps a faster rate of growth in the right brain versus left brain during childhood and adolescence makes it more likely that developmental lags in growth in this area may show up more prominently on the right side.

“We suspect that brain development for some of the adolescents catches up by adulthood. Nevertheless, they are more vulnerable as teens. We have found in our studies that teens from families with a history of alcohol dependence begin drinking earlier. This pattern in such a vulnerable group of teens can set up a pathway toward alcohol dependence lasting into or even through adulthood.

“Additionally, there is evidence that the brains of teenagers may be more susceptible to the negative consequences of heavy alcohol consumption,” said Hill. “Our research shows that, in kids from families with a history of alcohol dependence, some of these changes actually appear before they start drinking, which points to a strong genetic influence.”

For the study, Hill’s team examined 34 adolescent and young adult male participants identified as high risk because of their strong family history. Of that group, 22 were part of a larger study begun in 1990 to look at alcohol dependence. Because the researchers had been following them for about seven years, they had yearly evaluations from which to draw data.

The researchers used magnetic resonance imaging to examine brain structure and calculated the average size of each group’s amygdalas. In addition to imaging, all subjects received a number of clinical evaluations to determine IQ, cognitive function, and the presence of affective disorders such as depression or anxiety. This enabled the researchers to make sure that the high-risk group of adolescents from the multigenerational alcohol dependence families were well-matched to the control participants who did not have a family history of alcohol dependence.

Hill’s research was supported by the National Institute of Alcohol Abuse and Alcoholism.

—Craig Dunhoff