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.