Can you hold your liquor? Study debunks alcoholics' higher tolerance myth

People diagnosed with alcohol use disorder are frequently believed to have a higher tolerance to alcohol. However, according to a recent study, they may be even more impaired than normal after heavy drinking. 

The findings of this study were published in the peer-reviewed academic journal Alcoholism Clinical and Experimental Research.

This research debunks some common misconceptions about alcohol tolerance, showing that "holding one's liquor" is far more nuanced than initially thought.

How alcohol use disorder sufferers still get intoxicated

The researchers behind the study sought to examine how drinking alcohol would impact the cognitive and motor functionality of people with alcohol use disorder, based on the assumption that heavy drinkers would be less impaired. 

The logic behind this commonly-held belief is that heavy drinkers would be more used to alcohol and its effects compared to lighter drinkers and therefore less sensitive.

Previous studies had indicated this may have been the case, but there were also limits to the studies. Most relevant is the fact that all of these studies didn't adequately examine behavioral tolerance, especially not between heavy drinkers with alcohol use disorder (also known as alcoholism) compared to those without.

To figure this out, the researchers from the University of Chicago gathered three groups of participants, all of whom were young between the ages of 21 and 35, and all of whom had different drinking habits.

The three groups were those who were:

• Light drinkers – meaning they had six or fewer drinks per weak and rare binge drinking
• Heavy drinkers – meaning they regularly had at least 10 drinks each week with 1-5 heavy drinking episodes per week
• Drinkers with alcohol use disorder – meaning they had 28 drinks per week and at least 11 heavy drinking instances each month

Before testing them, the participants in each group had to abstain from alcohol and drugs for 48 hours and from food, caffeine, and cigarettes for three hours. They were then given snacks and alcohol.

What the results found is that when drinking the standard dose of alcohol for intoxication – enough to produce a breathalyzer reading of 0.08%-0.09% – the participants with alcohol use disorder were indeed less impaired regarding motor skills and cognition than the other groups. 

However, that's just the standard amount to get drunk, and it is a figure that didn't take into account the fact that people with alcohol use disorder still drink to get drunk, they just do so in greater quantities.

For comparison, a breathalyzer reading of 0.08%-0.09% is enough to qualify as driving under the influence and can be accomplished by having four or five drinks. But the drinkers with alcohol use disorder tended to drink more as part of their usual habits, around seven to eight drinks, with breathalyzer readings of 0.13%. 

So what happens when the participants with alcohol use disorder drank their usual amounts? Here, the researchers noted that they showed significant impairment – in fact, they were more impaired than the other groups after drinking four to five drinks.

Even three hours later, the participants with alcohol use disorder didn't sober up, and the impairment lasted for quite a while. 

"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," explained lead author Dr. Andrea King in a statement. 

She further said that she hopes this and the many other studies she has led since 2004 on alcohol use as part of the Chicago Social Drinking Project could help lead to a more nuanced understanding of being drunk, with could help prevent more harm and deaths from alcohol-related incidents. 

"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."