A study out of Durham University (not a university in Durham, North Carolina, a fine institution in its own right) suggests that people who consume the equivalent of seven cups of instant coffee a day are three times more likely to hear things that aren’t there than those who consume little to no caffeine.
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 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. Seeing things that were not there, hearing voices, and sensing the presence of dead people were amongst the experiences reported by some of the participants.
Seven cups sounds like a lot until you consider that, at least in the U.S., 1) seven cups of instant coffee is equivalent to about five cups of brewed coffee, and 2) a “cup” is considered to be 8 ounces, far less than those of us suckling at the teat of Dunkin’ Donuts and its cousins with their 24-ounce XL methylxanthine bombs will ever chug in a sitting. 40 ounces of brewed coffee a day is nothing to some of us. Fortunately, I remain firmly grounded in reality, although I’m a little annoyed that my keyboard won’t stop playing Herbie Hancock tunes every time I enter a blog post (and AC/DC whenever I rip into Concord Monitor commenters).