Although children of alcoholics (COAs) have a greater risk of developing alcohol-use disorders (AUDs), not all COAs will develop AUDs.
This study used functional magnetic resonance imaging (fMRI) to examine brain responses to emotional stimuli in adolescent COAs considered “vulnerable” or “resilient” to AUDs. Findings indicate that resilient COAs have greater control over their emotional responses, while vulnerable COAs seem to have difficulties processing emotional stimuli.
Results are published in the March issue of Alcoholism: Clinical & Experimental Research.
“COAs are between four and ten time more likely than non-COAs to develop AUDs,” said Mary Heitzeg, research investigator in the psychiatry department at the University of Michigan, and lead author for the study. “It is widely believed that this is due to a combination of genes that are passed on and the environment these children are raised in. Both of these factors – genetics and environment – can influence the developing brain. Therefore, our research focuses on what brain responses can tell us about how risk is passed on to COAs.”
Heitzeg and her colleagues recruited 28 adolescent participants (15 males, 13 females), 16 to 20 years of age, from a community study of alcoholic and matched “control” families. Of these, 22 were COAs: 11 were considered vulnerable for later alcoholism since they were already showing signs of problem drinking, and 11 were considered resilient, based on low levels of problem drinking during the course of their adolescence. The remaining six adolescents were considered low-risk “controls.” All of the participants were given a task of passively viewing positive, negative and neutral words during fMRI, and their neural activation was then compared. Behavior problems were assessed with the Youth Self-Report.
“The really interesting part of our results is that we found separate brain regions that contribute to resilience versus vulnerability,” said Heitzeg, “as opposed to finding that the groups were simply performing at different levels along the same scale. The resilient group had greater responses in two brain regions – the orbitofrontal cortex, which monitors emotional stimuli and evaluates it so that the right response can be made to it; and the insula, which also has an emotional monitoring function but one that is directed more toward the internal emotional state. In contrast, the vulnerable group showed no difference from the control group in those two regions.”
“The authors speculate that this may indicate that resilient COAs have enhanced awareness of their emotional responses, particularly effective emotional processing,” said Duncan Clark, associate professor of psychiatry at the University of Pittsburgh Medical Center. “This enhanced processing may lead to their being less likely to react to emotions in an impulsive fashion.”
“Conversely, the vulnerable group showed an increased response in an area of the prefrontal cortex believed to be involved in conscious regulation of emotional responses, and a corresponding decrease in the amygdala and ventral striatum, which are areas of the brain that are involved in unconscious emotion processing,” said Heitzeg.
“A pattern suggesting less subcortical activation in response to negative emotional stimuli,” said Clark, “means that vulnerable COAs may have more difficulty with negative emotional stimuli due to less effective processing.”