UChicago Medicine research challenges notion that heavy drinkers more tolerant of effects than others

Those with alcohol use disorder who consumed a high amount of liquor showed significant impairment in study

New research from the University of Chicago found that very heavy drinkers display the same impairment as light drinkers when consuming their usual excessive amount.

The study suggests that the concept of “holding your liquor” is more nuanced than commonly believed. They found heavy drinkers could tolerate some alcohol better than light drinkers, but that disappeared when the heavy drinkers drank their typical amounts.

“There's a lot of thinking that when experienced drinkers (those with alcohol use disorder) consume alcohol, they are tolerant to its impairing effects,” said Andrea King, professor of psychiatry and behavioral neuroscience at UChicago and senior author of the study. “We supported that a bit, but with a lot of nuances. When they drank alcohol in our study at a dose similar to their usual drinking pattern, we saw significant impairments on both the fine motor and cognitive tests that was even more impairment than a light drinker gets at the intoxicating dose.”

The new paper, published June 18 in Alcohol: Clinical and Experimental Research, is part of the Chicago Social Drinking Project, an ongoing research study started by King in 2004 that examines the effects of common substances like alcohol, caffeine, and antihistamines on mood, performance, and behavior in people with a wide range of alcohol drinking patterns.

A study of different drinking patterns

The authors of the study explained that most research on alcohol’s acute effects on motor and cognitive performance has focused on social drinkers, rather than those with alcohol use disorder (traditionally known as alcoholism). This has limited our ability to understand behavioral impairments in that group.

For this study, they worked with three groups of adults in their 20s with different drinking patterns.

The groups were: light drinkers who do not binge-drink; heavy social drinkers who binge-drink several times a month (defined as consuming five or more drinks for a man or four or more for a woman); and drinkers who meet the criteria for alcohol use disorder and binge-drink 11 or more days in a typical month.

They had each group consume a set amount of alcohol and tested their performance on both a fine motor task and a paper-and-pencil cognitive skill test.

When given a standard intoxicating dose, which produce breathalyzer readings of 0.08%, the light drinkers were more impaired than the heavier drinkers.

Yet when those drinkers with alcohol use disorder consumed a higher amount, akin to their usual drinking habits, they showed significant impairment on those same tasks—more than double their impairment at the standard intoxicating dose. They did not return to baseline performance for at least three hours after drinking.

Their level of impairment even exceeded that of the light drinkers who consumed the standard dose, suggesting that the physical effects of the alcohol add up the more someone drinks, experienced or not.

“I was surprised at how much impairment that group had to that larger dose, because while it’s 50% more than the first dose, we’re seeing more than double the impairment,” King said. 

The double-edged sword of intoxication

King’s group has conducted other research showing that heavy social drinkers and those with AUD are more sensitive to the pleasurable effects of alcohol, and want to drink more alcohol than their lighter drinking counterparts, compounding the issue. “They’re having the desire or craving to drink more and more, even though it’s impairing them. It’s really a double-edged sword,” she said.

Annual deaths caused by drunk driving have fallen significantly after the national minimum drinking age was set at 21 in 1984 and the public awareness campaigns that followed. Despite these successes, the Centers for Disease Control and Prevention reports that more than 140,000 people die from excessive alcohol use in the U.S. each year, and 30% of traffic fatalities still involve alcohol intoxication. King says that a more nuanced understanding of the effects of intoxication could begin to prevent more harm.

“It's costly to our society for so many reasons, that's why this study is just so important to understand more,” she said. “I'm hoping we can educate people who are experienced high-intensity drinkers who think that they’re holding their liquor or that they’re tolerant and won’t experience accidents or injury from drinking.  Their experience with alcohol only goes so far, and excessive drinkers account for most of the burden of alcohol-related accidents and injury in society. This is preventable with education and treatment.”

Additional authors of the study include Nathan Didier, Ashley Vena, Abigayle Feather, and Jon Grant from the University of Chicago.

Citation: “Holding your liquor: Comparison of alcohol-induced psychomotor impairment in drinkers with and without alcohol use disorder.” Didier et al, Alcohol: Clinical and Experimental Research, June 18, 2023.

Funding: National Institute on Alcohol Abuse and Alcoholism and the National Institute on Drug Abuse.

—Adapted from an article first published by the University of Chicago Medicine.