Time to cut out caffeine? In association with the NHS Caffeine consumption may be the root of many common problems. Health Reporter HELEN RAE looks at new research which suggests we may need to cut back.
HIGH caffeine consumption could be linked to a greater tendency to hallucinate, research suggests.
People with a higher intake, from sources such as coffee, tea and energy drinks, are more likely to report hearing voices and seeing things that are not there, according to a Durham University study.
High caffeine users - those who consumed more than the equivalent of seven cups of instant coffee a day - were three times more likely to have heard a person's voice when there was no-one there, compared with low caffeine users who consumed less than the equivalent of one cup a day.
The researchers say the findings will contribute to the beginnings of a better understanding of the effect of nutrition on hallucinations.
Changes in food and drink consumption could place people in a better position to cope with hallucinations or possibly impact on how frequently they occur, said 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. Their proneness to hallucinatory experiences and their stress levels were 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 was published in the academic journal Personality and Individual Differences, say their finding could be down to the fact that caffeine has been found to exacerbate the physiological effects of stress.
When under stress, the body releases a hormone which is called cortisol.
More of this hormone is released in response to stress when people have recently had caffeine. It is this extra boost of cortisol which may link caffeine intake with an increased tendency to hallucinate, say the scientists.
Lead author Simon Jones, a PhD student at 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, in part 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 hallucination-proneness in students.
"However, one interpretation may be students who were more prone to hallucinations used caffeine to help cope.
"More work is needed to establish whether caffeine consumption, and nutrition in general, has an impact on those kinds of hallucination that cause distress."
Facts about caffeing
CAFFEINE is a central nervous system stimulant, having the effect of temporarily warding off drowsiness and restoring alertness.
With 90% of North Americans consuming some form of caffeine every day, it is the world's most widely used drug In its pure state, caffeine is a crystalline white powder. Caffeine is completely absorbed by the stomach and small intestine within 45 minutes of ingestion.
When taken in moderation studies have shown that caffeine can increase the capacity for mental or physical labour.
Caffeine use can lead to a condition called caffeine intoxication. Symptoms include nervousness, irritability, anxiety, muscle twitching, insomnia headaches, and heart palpitations. This is not commonly seen when daily caffeine intake is less than 250mg.
STUDY - Dr Charles Fernyhough; AUTHOR - Simon Jones