Caffeine junkies shouldn’t always trust their ears, according to a new study. Subjects who drank the equivalent of seven cups of coffee proved three times more likely to hear voices, and slightly more likely to experience other hallucinations, than those consuming less than a cup’s worth. Researchers theorize that the cortisol hormone caffeine releases may trigger or exacerbate psychotic experiences, Scientific American reports.
“The prevalence of hallucinations is probably greater than people would expect,” says one researcher. Every year 5% to 10% of the population experiences some form of hallucination, including hearing voices and seeing things that aren’t there. The research doesn’t conclusively pin caffeine as a cause of those delusions, however; researchers are looking into sugar and fat as well.