The average person drinks for several reasons. Quaffing a glass of merlot is a much easier and more passive way to unwind than doing yoga or going for a run at the end of a long day. Alcohol increases levels of the pleasure-inducing neurotransmitter dopamine—it's like a little stash of candy for the brain. Drinking also promotes muscle relaxation. But alcohol doesn't reduce anxiety. "If you've spent all day in New York City traffic, alcohol can be a wonderful relaxant," says Vaillant, "but it won't alleviate an anxiety disorder."

Loosening up and having fun were by far the most frequently cited reasons for drinking in the O poll. "When I drink I feel social and fun! Very much the opposite of my sober self," says Kristy Bales, 30, of Seattle. Fortunately, Kristy has strong internal controls. "Alcohol has almost become sacred to me; I like to share it with friends on special occasions."

Every culture has its means of achieving altered states of consciousness. Drinking is our accepted mode of transport from the daily grind into some other realm. But it certainly doesn't qualify as the healthiest pastime. It all comes down to that old adage Everything in moderation. Follow the example of Brittany Marr: "I've learned to balance drinking with living a healthy life, where it's okay to have a glass of wine but also know when to say no. Then I can wake up the next morning and hit the trails of Boulder."

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