Study: Heavy Coffee Consumption May Cause Hallucinations

If you are a heavy coffee drinker, you might be hearing things. So says La Trobe University professor Simon Crowe, who says his research shows heavy coffee users are prone to hallucinations.

Crowe and his fellow researchers measured the effect of stress and caffeine on 92 non-clinical participants. They found high caffeine levels, along with lots of stress, produced higher levels of hallucination.

Crowe defines heavy coffee consumption as drinking at least five small cups of coffee a day. How did they reach their conclusion about heavy coffee use causing auditory hallucinations?

In an interview with the BBC, Crowe said the participants all drank at least five cups of coffee and were then asked to listed to Bing Crosby's classic Christmas song, “White Christmas.”

Can you hear it now?

After that, they were asked to listen to several minutes of white noise, similar to radio static. They were told that the song “White Christmas” might be played softly under the white noise at several intervals and were told to listen for it and report when they heard it.

“The ones who were highly stressed and had consumed a lot of coffee were three times more likely to report hearing 'White Christmas' several times, when in fact we had not played it at all,” Crowe told the BBC interviewer.

Crowe said caffeine is not as dangerous as amphetamines, but is much more common in society. The point, he says, is that “safe” drugs like caffeine need to be handled with care.

“We are shifting in our drug usage from illicit drugs to licit drugs,” Crowe said.

Coffee, perhaps the world's most popular beverage, has been the subject of scientific research for decades, with scientists alternately finding health risks or benefits associated with its use. Just last month new research linked coffee consumption with a lower rate of prostate cancer.