Coffee overdose causes visions

Published on Tuesday 13 January 2009 19:08

TOO much coffee not only makes sleeping difficult but can also appear to wake the dead, scientists claim.

People who drink more than seven cups of instant coffee a day have an increased tendency to hallucinate – and they may even think they sense ghosts, according to research.

High caffeine users were three times more likely to have heard voices than "low" users who consumed less than one cup of instant coffee or its equivalent, scientists found. Besides coffee, caffeine can be obtained from sources such as tea, chocolate, "pep" pills and energy drinks.

The researchers from the University of Durham pointed out that hallucinations were not necessarily a sign of mental illness and about 3 per cent of people regularly heard voices. They studied 200 students who were asked about their typical intake of caffeinated products.

The students' susceptibility to hallucinatory experiences and stress levels were also assessed.

Among the experiences reported were seeing things that were not there, hearing voices, and sensing the presence of dead people.

Caffeine's ability to exacerbate the effects of stress may explain the findings, the scientists believe.