Ingesting the amount of caffeine contained in seven cups of instant coffee could cause drinkers to experience hallucinations, according to researchers at Durham University.

Bloomberg reported Jan. 14 that individuals who consumed more than 330 mg of caffeine daily were three times more likely to experience hallucinations than those who consumed less than 10 mg of caffeine daily. The study focused on the relationship between caffeine consumption and release of cortisol, a stress hormone that researchers believe may be linked to delusions.

Lead researcher Simon Jones cautioned, however, that people under stress and more prone to hallucinations may simply consume more caffeine. "There would be no real reason for me to stop drinking tea," he said. "I don't see a reason to change a moderate intake."

The study was published online in the journal Personality and Individual Differences.