Here’s something to keep in mind as the holidays unfold: if you drink alcohol when you’re stressed, you may be flipping a brain switch that makes heavier drinking all the more likely. That’s the finding of a new animal study on the neural effects of drinking, and stressed humans should take note of the results. A group of rats were put under heavy stress for an hour, and 15 hours later their blood was tested to find out how much of a sugar-water and ethanol solution they’d been drinking (rodent version of a stiff cocktail served at an open bar). The researchers found that the stressed rats drank significantly more of the solution than an unstressed control group. And here’s the really interesting part: the booze slurping went on for weeks after the original exposure to stress.