It's nothing you didn't already know, but new research from Australia has found that if you're hyped up on caffeine from a few cups of coffee, you may hear things that aren't really there.
In a recent study involving 92 subjects at La Trobe University in Victoria, psychology Professor Simon Crowe found that five cups of coffee a day or more -- plus a little stress -- was enough to cause auditory hallucinations.
The results show that "further caution needs to be exercised with the use of this overtly 'safe' drug," Professor Crowe said.
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The participants were assigned to either a high- or low-stress condition and a high- or low-caffeine condition based on self-reporting. The subjects were then asked to listen to white noise and to report each time they heard Bing Crosby's rendition of "White Christmas" during the white noise. The trick: "White Christmas" was never actually played. (Ironically, the song itself is about hallucinating.)
The study found that the interaction of stress and caffeine had a significant effect on the reported frequency of hearing the classic Christmas tune. The participants with high levels of stress and/or those who consumed high levels of caffeine were more likely to hear the phantom song.
"There is a link between high levels of stress and psychosis, and caffeine was found to correlate with hallucination proneness. The combination of caffeine and stress affect the likelihood of an individual experiencing a psychosis-like symptom," Professor Crowe concluded. "It is apparent that the health risks of excessive caffeine use must be addressed and caution should be raised with regards to the exacerbating use of this stimulant."
Maybe this explains why there are so many weirdos in Starbucks.