In a study on adolescent binge drinkers, scientists have found that even rare consumption of large doses of alcohol during youth may compromise the coherence of the brain's white matter fibre.
Such incoherence has been known in adult alcoholics, but researchers were unaware as to when during the course of drinking white matter abnormalities become apparent.
"Because the brain is still developing during adolescence, there has been concern that it may be more vulnerable to the effects of neurotoxins, such as high doses of alcohol," said Susan F. Tapert, associate professor of psychiatry at the University of California, San Diego.
The study's corresponding author has claimed that animal studies have suggested this to be true.
Duncan Clark, associate professor of psychiatry at the University of Pittsburgh Medical Center, said that "'white matter'" refers to brain areas that appear light in colour due to being primarily lipids."
He added: "White matter is composed of bundles of myelinated axons connecting grey matter areas of the brain, and has been shown to continue to develop throughout adolescence. These systematic changes in white matter organization reflect not only maturation of interconnections but continued maturation of the brain as a whole."
"White matter, and its integrity, are essential to the efficient relay of information within the brain. Indicators of white matter integrity are linked to performance on a range of cognitive tests, including measures of reading, copying complex figures, and speeded coding of information. Abnormalities in white matter health could relate to compromised ability to consider multiple sources of information when making decisions, and to emotional functioning," said Tapert.
For the study, the researchers enrolled 28 teens and used diffusion tensor imaging - an MRI technique sensitive to the random movement of water in cells of a target tissue - to examine fractional anisotropy, a measure of directional coherence of white matter tracts, in them.
It was found that out of the 28 adoloscents, 14 (12 males, 2 females) had and 14 (12 males, 2 females) did not have histories of binge drinking.
No participants had a history of an alcohol use disorder-drinkers were matched to non-drinkers on age, gender and education.
"This study showed that adolescents with histories of binge drinking episodes have lower coherence of white matter fibers, suggesting poorer white matter health, in a variety of brain regions. Frankly, I was surprised we found this, because the drinkers did not meet criteria for alcohol abuse or dependence," said Tapert.
Clark said: "These findings add to a growing literature indicating that adolescent alcohol involvement is associated with specific brain characteristics. One of the advantages of this study was that the adolescents with binge drinking did not have major mental disorders. Adolescents with alcohol-use disorders often have other problems. This suggests that the observed brain characteristics may be associated with alcohol involvement specifically rather than other complications."
"These findings indicate that adolescents who engage in binge drinking show low levels of brain organization," he said. "This characteristic could be a risk factor for accelerated alcohol use or an effect of alcohol. We need to know more about how alcohol influences adolescent brain development, [given] that alcohol may disrupt brain development."
The results of the study will be published in the July issue of Alcoholism: Clinical and Experimental Research and are currently available at Early View.