Can you tell if you have had too much to drink? Do you count alcohol units, or try walking in a straight line? Turns out we base our judgment on the sobriety – or not – of those around us. Research from four Welsh city-centre pubs and clubs, published in the journal BMC Public Health found that people were more likely to underestimate how much alcohol they had drunk when surrounded by others who were inebriated. Such company also made them feel more relaxed about the health risks of boozing.

The solution

So should you just stick around heavy drinkers and feel sober in comparison? No, says Professor Simon Moore of Cardiff University and lead author of the paper, because drinking excessively puts you at risk from violence, alcohol poisoning and inhaling your own vomit. The study involved breathalising 1,862 people who were on average 27 years of age, between 8pm and 3am on Friday and Saturday evenings. They asked a subset of 400 of them questions including: “How drunk are you right now?” and “If you drank as much as you have tonight every week, how likely is it that you will get cirrhosis of the liver in the next 15 years?” On average, people thought they were moderately drunk and moderately at risk. Their breath alcohol concentration was an average of 47.3mg of alcohol in 100ml of breath – the drink-driving limit is 35mg.

But what Moore found so interesting was that at the same level of breath-alcohol concentration, people who were surrounded by heavier drinkers ranked themselves as less intoxicated than those out with more modest boozers. “People don’t see an objective reality,” says Moore. “Their feelings of risk and intoxication are not based on the perceptions of the individuals themselves.” Moore, a public-health doctor, worries that being out late in city-centre pubs and clubs makes severe intoxication seem normal because everyone is in that state.

So, don’t compare how drunk you are with the state of your mates, as you will get it wrong. Pace yourself – intersperse alcohol with soft drinks, don’t go for premium lager with its heftier alcohol content, drink slowly, eat first and avoid spirits. Take a designated driver with you who, by remaining sober, will make you feel seriously drunk within a couple of hours. This study, by the way, should not just be of interest to students and those under 30 years of age: Moore points out that we are all constantly ranking ourselves against others, including on how happy and wealthy we are. Now have one more ranking system: how much more likely we are than others to get liver cirrhosis.