But a new report suggests that sometimes things are more complicated than that. When it comes to serious head injuries, people who have drunk moderate amounts of alcohol seem to be at less risk of dying than people who are sober. The report appears in The Archives of Surgery, and its authors were at pains to say they were not endorsing heavy drinking, especially during the holiday season. Heaviest drinkers, anyway, were the most likely to die.

“Certainly, if you take all things equally, if you drink and drive you’re still much more likely to die from an accident,” said the lead author, Dr Homer CN Tien of the University of Toronto, in an interview.

The researchers nevertheless found clear evidence that in some cases, a certain amount of alcohol helps the brain recover from blunt trauma injury. And those findings, they said, could lead doctors to develop head injury treatments that involve alcohol preparations.

They did, however, point out that as many as half of all patients hospitalised with trauma were intoxicated when they were hurt. Alcohol is believed to play a role in about a third of all deaths from injury. And by impairing motor skills, reaction time and judgment, alcohol increases the risk of injury in almost every imaginable way, leading to car crashes, falls, assaults and self-inflicted wounds.

But, “not all of the injury in the brain happens right away”, Tien said. Instead, in the hours after the initial trauma, the brain undergoes a series of changes as it tries to fix the damage. In some cases, the flood of neurotransmitters it puts out can actually do more harm than good.

Alcohol, the researchers believe, may act to slow the release of some of those neurotransmitters. The researchers pointed to other studies that have reported that alcohol and caffeine may make strokes less severe. But of course, the popular myth that alcohol helps intoxicated drivers avoid injury by relaxing them is just that: a myth.

—ERIC NAGOURNEY / NYT