Caffeine's Mental Boost Could Be Just In the Mind

By Anthony Daconti 09/06/11

London researchers discover a pronounced placebo effect among people who falsely believe they're drinking real coffee.

Some will go to any lengths. Photo via

Most people think a caffeinated cup of coffee in the morning helps boost their mental performance all day. But a new British study suggests that the pick-me-up power of a morning cup of Joe could be all in your head. A team from the University of London set out to investigate the power of the placebo effect in coffee drinkers, enlisting 88 students in the habit of downing at least two caffeinated cups every day. The researchers gave caffeinated coffee to two groups of volunteers and decaffeinated coffee to another two groups—but lied to half of them about the caffeine content in their coffee. Those who were truthfully told they had caffeinated coffee showed a significant improvement in performance—but not in reaction time. Those who were told they had caffeinated coffee—but didn't—performed better in both performance and reaction time. This suggests that attention and psychomotor function improved whether subjects really drank caffeinated coffee or simply thought they did. All volunteers reported feeling more depressed over the course of the testing, which doesn't say much for the researchers' conversational skills—but those who drank or thought they drank caffeine didn’t feel as glum as the others. There may be another reason for caffeine drinkers to cheer up: other researchers believe regular coffee intake might help prevent or delay the symptoms of Alzheimer’s disease. Brits drink around 70 million cups of coffee a day, according to the British Coffee Association, while Americans take over 330 million cups daily—and counting. According to researchers, the University of London study suggests "the expectation of having consumer caffeine confers an enhancement on sustained attention that is at least comparable, and perhaps superior to, the effects of caffeine.” In other words, your morning mental boost may indeed be confined to your mind. 

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