High caffeine consumption link to hallucination
15 January 2009
People with a high caffeine intake, from coffee, tea and caffeinated energy drinks, are more likely than others to report hallucinatory experiences according to a study from Durham University’s Department of Psychology.
The study found that ‘high caffeine users’, those who consume more than the equivalent of seven cups of instant coffee, were three times more likely to have heard a person’s voice when there was no-one there compared with ‘low caffeine users’, people who consume less than the equivalent of one cup of instant coffee a day.
The researchers say the finding will contribute to the beginnings of a better understanding of the effect of nutrition on hallucination. Changes in food and drink consumption, including caffeine intake, could place people in a better position to cope with hallucinations or possibly affect how frequently they occur, say the scientists.
In the study, funded by the Economic and Social Research Council and the Medical Research Council, 200 students were asked about their typical intake of caffeine from products including coffee, tea, energy drinks, chocolate and caffeine tablets.
Their propensity to hallucinatory experiences and their stress levels were also assessed. Seeing things that were not there, hearing voices, and sensing the presence of dead people were among the experiences reported by some of the participants.
The researchers, whose paper is published in the academic journal Personality and Individual Differences, say their findings could be attributed to the fact that caffeine is known to exacerbate the physiological effects of stress. When under stress, the body releases a hormone called cortisol. More cortisol is released in response to stress when people have recently had caffeine. It is this extra boost of cortisol that may link caffeine intake to an increased tendency to hallucinate, say the scientists.
The lead author, Simon Jones, a PhD student in Durham University’s Psychology Department, said:
“This is a first step towards looking at the wider factors associated with hallucinations. Previous research has highlighted a number of important factors, such as childhood trauma, which may lead to clinically relevant hallucinations. Many such factors are thought to be linked to hallucinations, partly because of their impact on the body’s reaction to stress. Given the link between food and mood, and particularly between caffeine and the body’s response to stress, it seems sensible to examine what a nutritional perspective may add.”
Co–author Dr Charles Fernyhough said:
“Our study shows an association between caffeine intake and proneness to hallucination in students. However, one interpretation may be that the students who were most prone to hallucinations used caffeine to help cope with their experiences. More work is needed to establish whether caffeine consumption, and nutrition in general, has an impact on the kinds of hallucination that cause distress.”
Mr Jones added:
“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 three per cent of people regularly hear such voices. Many of these people cope well with this and live normal lives. There are, however, a number of organisations, such as the Hearing Voices Network, who can offer support and advice to those distressed by these experiences.”
Research in this area continues and the public can take part in studies at www.dur.ac.uk/s.r.jones
Press contact: 020 7637 6011
press.office@headoffice.mrc.ac.uk
