BioEd Online

A trawl through the journal Addiction this week comes up with this startling find: a hangover makes you feel out of sorts, and affects your cognitive performance.

Well, quite. I might be fairly wet behind the ears as a columnist, but I know the effect that getting sloshed the night before can have. Did someone really need to prove this?

According to lead researcher Frances Finnigan of Glasgow Caledonian University, UK, we apparently lacked hard scientific facts to back up this subjective experience. "Ok, it's common sense," she tells me on the phone, "but there have not been studies, only anecdotal evidence."

Let's be clear. People have tried to quantify the effects of hangovers in the lab, and work out what properties of a night out are most likely to create nasty feelings in the morning. People have tested hangover cures. And alcohol itself has been studied ad nauseam. Literally.

But Finnigan says there is a dearth of studies done with 'real' hangovers.

Lab rats

The biggest drawback of testing boozing in the lab is that telling subjects to drink themselves stupid, especially if they may acutely impair their health by doing so, presents ethical problems, says Finnigan. That's where her team has the edge: they tested people who voluntarily went out and got drunk.

In their 'naturalistic' approach, Finnigan's team tested more than 70 volunteers on a range of tasks to evaluate concentration, reaction times and memory. Half of these were asked to repeat the tests some days later when they had a clear head; the other half were asked to call back the next time they had got really drunk the night before.

Finnigan found that those with hangovers performed less well on the concentration and reaction time tests, but did just as well on the memory test as they did with a clear head¹. So despite the logistical difficulties inherent in asking people to come into an office when they have a stinking hangover, the results confirm that life is indeed a struggle the morning after a real-life drinking session.

Sore head

Okay, that's not a shocker. But I am all for pinning down the exact symptoms of a natural hangover, if it helps us get at the interesting question that's still unanswered: what that horrible feeling is actually due to. The symptoms have variously been ascribed to simple dehydration, brain swelling, changes to the brain's serotonin balance, and even to impurities other than alcohol lurking in some drinks. Still, no one really knows the cause of that nasty feeling. Maybe studying hangovers in their natural environment will help unravel the mystery.

And, strangely, the study accidentally shed some light on another phenomenon that might have great importance in the real world. It turns out that a lot of the 'hungover' volunteers were actually still drunk, even though they didn't know it. "Most were surprised by that," Finnigan recalls. And the performance in the cognitive tasks of the still-blotto subjects was even worse than that of the merely hungover.

So maybe the take-home message is to underline once again the fact that mere sleep does not stop you being too drunk to drive or do your job. At least I think that's the point. To be honest, the room has started spinning a bit now. I might go and have a lie down.