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Coffee buzz may be all in your head

Phil Noble / Reuters

If you’re one of those people who can’t start the day without a jolt of java, the mere thought of decaf is probably enough to put you to sleep.

But a new study suggests you really needn’t worry that your favorite breakfast hangout one day will accidentally put decaf in the caffeinated carafe. As long as you think you’re getting the high-octane stuff, you’re likely to respond accordingly. You’ll feel happier and mentally sharper, the same as if you’d actually downed a dose of liquid lightning.

In other words, caffeine is in the mind of the drinker -- not necessarily his or her cup.

To investigate the power of this placebo effect in coffee drinkers, University of London researchers enlisted the help of 88 students, ages 18 to 47, who drank at least a couple of cups of caffeinated coffee a day. The scientists told the students only that they were studying the effects of caffeine on mood and brainpower.

The students were divided into four groups, each consisting of 11 men and 11 women.

People in two of the groups were given a cup of caffeinated coffee to drink, although one of those groups was told their coffee was decaf. 

People in the other two groups were given a cup of decaf, although the researchers told one group that they were getting caffeinated coffee.

The students drank their coffee in five minutes and then chilled for 55 before taking tests to evaluate mood and brainpower.

You know where this is going. Turns out that both drinking caffeine and the mere belief that they had drunk caffeine improved the students’ attention and the speed at which they could perform a card-sorting task, a measure of psychomotor function.

In addition, while students in all four groups reported feeling more depressed over the course of the testing, those who drank or thought they drank caffeine didn’t feel as glum as the others.

Expecting to drink caffeine and actually drinking caffeine did not have a synergistic effect, though, as some previous research has found.

Now, the scientists, who published their findings in the journal Appetite, aren’t suggesting that you could stroll into Starbucks and order a decaf espresso and feel the same lift you get from your regular caffeine fix. See, the placebo effect doesn’t work if you’re onto it.

But if your partner’s caffeine intake is keeping him or her up at night, maybe it wouldn’t hurt to secretly do the old switcheroo at home. Just make sure you dispose of the bag or jar or whatever your coffee comes in.