A report released today warns that people who drink coffee and products with caffeine in them are at risk of having hallucinations.
Researchers at Durham University discovered that the more caffeine students consumed, the increased likeliness of them hearing voices, smelling things and seeing things that weren’t there. The suggested reason behind this is the higher levels of the hormone cortisol released by caffeine.
Although caffeine can cause heart palpitations, there is no evidence to suggest any link to schizophrenia or related behaviour.
Researchers at the University got 219 non-smoking students to complete questionnaires on their caffeine intake, lifestyle and if they experienced feelings of hallucination or persecution. The answers removed any link between stress or feelings of persecution.
However, as caffeine intake increased, the hallucinations got worse. In the top 10 per cent of caffeine consumers having 330mg a day - seven cups of instant coffee or eight cups of tea - nine people heard things that were not there. Of the 22 people in the bottom ten per cent, only 3 people suffered similar hallucinations.
The study said, “The present study offers some support for our first hypothesis, namely that when levels of stress are accounted for, caffeine intake is positively related to levels of psychosis-like experiences,”
However, the authors, Dr Charles Fernyhough and Simon Jones do note that it was unclear whether the caffeine was solely to blame for hallucinations, or if it was due to the fact people with existing psychological disturbances were drinking coffee to alleviate their symptoms.
The psychologists commented that more research was necessary to determine whether drinking coffee could actually help people cope with hallucinations.
Mr Jones, a PhD student at Durham’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.”
He 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. Around three per cent of people regularly hear such voices.”
Caffeine occurs in different levels in a variety of drinks, foods and some medicines. In a medium cup of tea there is 40mg, 45mg in an instant cup of coffee, 188mg in a Starbucks espresso drink and 80mg in a Red Bull.
The British Coffee Association, the trade body for coffee processors, stated that the Durham University study was not a fair comparison as it only looked at high caffeine users.
The BCA’s executive director, Dr Euan Paul said, “Whilst the results from this preliminary investigation are interesting, the study has only investigated a very high level of caffeine intake - equivalent to consuming more than six cups of coffee per day,”
“Importantly for this population, whilst cigarette smokers were excluded from the study, no details of other substances consumed that may have hallucinogenic effects were included in the data.”
Numerous published studies have however concluded that consumption of around 400 to 500mg of caffeine a day was perfectly safe for an average person.
