A study of adolescent binge drinkers has found that even relatively infrequent exposure to large amounts of alcohol during the teen years may compromise the integrity of the brain's white matter, which is critical for the efficient relay of information within the brain.

The preliminary findings - to be published online in advance of the July issue of the journal Alcoholism: Clinical & Experimental Research - indicate that binge drinking may be detrimental to the developing adolescent brain.

Heavy episodic or "binge" drinking is common among adolescents, with 55% of high-school seniors reporting having gotten drunk, and a quarter of them reporting having consumed five or more drinks in a row during the previous two weeks.

"Because the brain is still developing during adolescence, there has been concern that it may be more vulnerable to high doses of alcohol," said Susan F. Tapert, PhD, director of Substance Abuse/Mental Illness at the VA San Diego Healthcare System and associate professor of psychiatry at the University of California, San Diego School of Medicine. "This study showed that teens with histories of binge drinking episodes have lower coherence of white matter fibers in a variety of brain regions."

"White matter" is the part of the brain made up of the axons of neurons - long filaments that extend from the cell bodies and carry the electrical signals that relay messages between neurons. The area appears white because of the axons' protective myelin covering.