Early alcohol may fuel heavy drinking, rats show

NEW YORK (Reuters Health) - In a study of adolescent rats, scientist saw that early alcohol exposure led to a tendency toward heavy drinking later on -- and the same might be true for humans.

"We know that adolescence is a vulnerable time," Dr. Nicole L. Schramm-Sapyta from Duke University Medical Center noted in a written statement, and many teens experiment with alcohol. "Our key finding is that drinking patterns may be established after only a few exposures to alcohol. Rats that demonstrated a 'taste' for alcohol after only three nights of drinking were very likely to be the biggest drinkers after longer-term exposure."

In the federally-funded study, the researchers studied 48 rats that were 28 days old -- the equivalent of rodent adolescence. During the first three nights of the study, the rats were given only 10-percent alcohol to drink. After that, for 10 days, they had a choice of water or alcohol.

The scientists found that the rats that drank the most alcohol on the third day of the study also drank the most alcohol in the later days of the study.

After that, the rodents were deprived of alcohol for two days and then again given a choice between alcohol and water. The rats that drank heavily at the beginning of the experiment returned to this alcohol consumption pattern when offered alcohol again.

These results suggest that "early exposure to alcohol may initiate a pattern of heavy drinking and increased vulnerability to relapse," the researchers write in the journal Alcoholism: Clinical and Experimental Research.

"The findings suggest that early 'big drinkers' are the people who should be targeted for alcoholism-prevention efforts," Schramm-Sapyta concluded.

She and her colleagues also tested the rats drinking habits after they determined their individual level of "novelty-seeking behavior" -- namely, their preference for seeking out new objects and for exploring a new place. They also monitored their drinking habits right after they had traveled through an elevated maze -- a way to raise anxiety levels and measure stress-related hormone levels. "We chose to examine novelty seeking and stress because these are two characteristics we see in some populations that develop problem drinking," Schramm-Sapyta explained.

Surprisingly, stress and novelty-seeking were not related to drinking patterns. "This suggests that there are other characteristics that we as scientists should be looking for, that are related to the early experiences of drinking," Schramm-Sapyta noted.

SOURCE: Alcoholism: Clinical and Experimental Research, May 2008.