NEW YORK  — A new study by a British university links high caffeine intake with hallucinatory experiences like hearing voices and seeing things that are not there.

The study out of Durham University quizzed 219 students about their consumption of coffee, tea, energy drinks and chocolate. The students were then asked about hallucinatory experiences and their stress levels. These finding were published Wednesday in the academic journal Personality and Individual Differences.

The survey found that students that fell into the “high caffeine users” category – consumers of more than seven cups of coffee a day – were more likely to report seeing or hearing something that was not there.

Researchers are attributing the hallucinations to the fact that caffeine has been found to exacerbate the physiological effects of stress.

Simon Jones, lead author and a PhD student at Durham University’s Psychology Department, said in a statement: “Hallucinations are not necessarily a sign of mental illness. Most people will have had brief experiences of hearing voices when there is no one there, and around 3 percent of people regularly hear such voices. Many of these people cope well with this and live normal lives. There are, however, a number of organizations, such as the HEARING VOICES NETWORK, who can offer support and advice to those distressed by these experiences.”