A new study on rhesus monkeys reveals that alcohol exposure before birth alters the brain's dopamine system, predicting faster drinking in adulthood. Researchers from the University of Wisconsin-Madison found these changes occur even before the animals consume alcohol. The findings highlight risks of drinking during pregnancy and align with human studies on alcohol use disorder.
Researchers led by Mary Schneider and Alexander Converse at the University of Wisconsin-Madison conducted a twenty-year longitudinal experiment with rhesus macaques to explore how prenatal experiences influence later behavior. Pregnant monkeys were divided into groups: some consumed moderate amounts of alcohol, others faced mild stress, and a third group experienced both. The offspring reached adulthood, at which point scientists measured changes in their dopamine systems—a key network for motivation and reward—and observed their alcohol consumption.
Both prenatal alcohol exposure and stress modified the dopamine system in the adult monkeys. Those exposed to alcohol in utero drank more quickly as adults compared to controls. Crucially, dopamine system assessments conducted before any adult alcohol intake accurately predicted this accelerated drinking behavior. As the monkeys consumed alcohol, further dopamine alterations emerged, varying by individual and influencing total intake. The team suggests these personalized brain responses could explain why some shift from moderate to problematic drinking.
The study, published in The Journal of Neuroscience, underscores that prenatal alcohol exposure links to unhealthy adult drinking patterns, reinforcing advice against alcohol during pregnancy. While prenatal stress altered the dopamine system, it showed no direct tie to adult drinking speed, though it may impact other unexamined behaviors. The experimental setup mirrors human prenatal exposures, enhancing relevance to clinical outcomes in alcohol use disorder.
