Too much coffee can lead to hallucinations

Jan 18 2009

The latest research from Britain says drinking too much coffee can cause hallucinations.

According to a study by researchers at Durham University people with a higher caffeine intake, from coffee, tea and caffeinated energy drinks, are more likely to experience hallucinatory experiences such as hearing voices and seeing things that are not there.

The study found that students who consumed more than the equivalent of seven cups of instant coffee a day were three times more likely to have had these kinds of hallucinations compared to people on a single daily cup.

Psychologist Simon Jones, who led the study says the study is the first step towards looking at the wider factors associated with hallucinations and these latest findings add to mounting evidence indicating the amount of caffeine a person consumes may directly affect a person's health.

While some research has found moderate consumption to be beneficial to the health in a number of ways, more recent research has found too much doubles the risk of miscarriage.

Caffeine is a stimulant which can temporarily ward off drowsiness and restore alertness and it is the world's most widely used drug.

Caffeine is completely absorbed by the stomach and small intestine within 45 minutes of ingestion and in moderation has been shown to increase the capacity for mental or physical labour - however too much caffeine can cause nervousness, irritability, anxiety, muscle twitching, insomnia, headaches, and heart palpitations.

For the study, 200 students were asked about their typical intake of caffeine containing products, such as coffee, tea and energy drinks ,as well as chocolate bars and caffeine tablets - their proneness to hallucinatory experiences and their stress levels, were also assessed but the students were not asked how much they slept.

Amongst the experiences reported by some of the participants were seeing things that were not there, hearing voices, and sensing the presence of dead people.

The researchers found that the students who consumed the most caffeine were more likely to report hallucinatory experiences.

The researchers say caffeine has been found to exacerbate the physiological effects of stress - when under stress, the body releases a stress hormone called cortisol and more is released in response to stress when people have recently had caffeine.

The researchers say it is this extra boost of cortisol which may link caffeine intake with an increased tendency to hallucinate.

Currently, people treated for hallucinations receive drugs or counselling but Jones said his research aims to explore whether changing a person's diet could help and the next step is to test whether caffeine is actually causing hallucinations or whether people who have them simply consume more caffeine when under pressure.

The researchers say the findings will contribute to the beginnings of a better understanding of the effect of nutrition on hallucinations and changes in food and drink consumption, including caffeine intake, could place people in a better position to cope with hallucinations or possibly impact on how frequently they occur.

Mr Jones says hallucinations are not necessarily a sign of mental illness and most people will have had brief experiences of hearing voices when there is no one there.

The study which was funded by the Economic and Social Research Council and the Medical Research Council, is published in the academic journal Personality and Individual Differences.