It's no secret that binge drinking and faulty decision-making go hand in hand, but what if poor judgment lingered long after putting the bottle down and sobering up? A new study with rats suggests that heavy alcohol consumption in adolescence could put people on the road to risky behavior.
Several studies have associated heavy drinking in youth with impaired judgment in adulthood, but these studies didn't resolve whether alcohol abuse actually predisposes people to develop bad decision-making skills, or if the people who indulged in excessive inebriation were risk-taking types to begin with. As Selena Bartlett, a director in the Ernest Gallo Clinic and Research Center at the University of California, San Francisco, explains, you cannot put adolescents in a room and ask them to consume alcohol to see what happens. But scientists can conduct these kinds of experiments with rats, an animal that Bartlett, who was not part of the study, says is "excellent for modeling changes in behavior" as a result of alcoholism.
In the new study published this week in Proceedings of the National Academy of Sciences, scientists at the University of Washington (U.W.) in Seattle fed alcohol to a group of rats and found that their ability to make good decisions was impaired even long after they stopped consuming booze.
Because rats do not normally have a taste for alcohol, the researchers sweetened the deal, literally, by mixing the liquor in glucose gelatin. For 20 days one group of rats helped themselves to these "Jell-O shots" (a second group downed a nonalcoholic version). Although the animals consumed large amounts of alcohol over the course of each day, they paced themselves, and did not show signs of drunkenness or withdrawal when the researchers cut them off. Several weeks after the guzzler rodents stopped receiving the spiked gelatin, the researchers trained the animals to push a pair of levers in order to receive sugar pellets.
The group of rodents that had been "dry" for the 20 days preferred the lever that led to the smaller and more consistent allotment of treats. The group that had consumed the alcohol, on the other hand, opted for the lever that, like a slot machine, offered a rare but hefty payoff. Even though the rats knew that the total number of treats from the second lever had never caught up with the output from the first, the alcohol-exposed group chased after the low likelihood of a sugar pellet windfall.
Going into the study, "the gut feeling was that we'd see a graded effect [on decision-making] that would be diminished" over time, says Nicholas Nasrallah, a graduate student in the U.W. Department of Psychology and the first author of the study. But the researchers found that the tendency to make imprudent decisions did not fade for up to three months after the rats stopped consuming alcohol.
To further investigate whether alcohol has a causal and lasting effect on decision-making, the group plans to see if the boozing rats have chemical changes in the areas of the brain that control valuation. "One of the studies that I'm most excited about," Nasrallah says, "is really watching the brain in real-time [to] see if there are differences in the way these areas seem to signal" in animals that were exposed to alcohol. Bartlett at the Gallo Center says that understanding the mechanisms that underlie risky behavior could allow her and others develop better treatments to help people recover from alcoholism.