A new study in rats suggests heavy drinking during the teen years could lead to structural changes in the brain that last into adulthood.
The changes occur in the region of the brain important in reasoning and decision-making.
The researchers found the rats given daily access to alcohol during adolescence had less myelin, the fatty coating on nerve fibers that speeds transmission of electrical signals between nerve cells.
The animals that drank the most performed worse on a memory test later in adulthood, the study found. The findings suggest binge drinking during adolescence could continue to affect the brain even long after the drinking stops. Further study is needed to determine if the findings also apply to humans, the researchers noted.
The findings are published in The Journal of Neuroscience.
According to study co-author Heather Richardson of the University of Massachusetts Amherst, previous studies have shown heavy alcohol use among teenagers is linked to changes in myelin and cognitive impairment later in life. Until now, it has been unclear whether these changes are directly caused by alcohol, Medical News Today reports.
The researchers studied two groups of male adolescent rats. One group had access to sweetened alcohol each day for two weeks. The other group had access to sweetened water. At the end of the study, the researchers analyzed the rats' myelin levels in the brain. The rats that drank alcohol had reduced myelin in the prefrontal cortex, compared with those that drank sweetened water.
Months later, when the rats reached adulthood, their levels of myelin were reassessed. The researchers found the rats that consumed the alcohol continued to show reduced myelin levels. Richardson noted in a news release, "These findings suggest that alcohol may negatively affect brain development in humans and have long-term consequences on areas of the brain that are important for controlling impulses and making decisions."