This article instantly caught my attention. You see, I'm a coffee drinker. I drink truckloads of coffee a day. Even more here in Korea, with all those different flavors of instant coffee available. Apparently, caffeine is linked to seeing ghosts. I read from skynews that a research from the University of Durham suggests that "people who drink more than seven cups of instant coffee a day have an increased tendency to hallucinate", "High caffeine users may even think they sense non-existent people", researchers say. Other experiences reported are seeing things that aren't there, hearing voices and sensing the presense of dead people. Oh my, this probably explains why I keep on seeing things on the corners of my eyes when I alone. Or the voices at night when the lights are off. Hehehe. Kidding aside, Dr Charles Fernyhough, the co-author of the study, pointed out that the research only showed an association between caffeine intake and hallucination proneness, not a causal link. Also other sources of caffeine are tea, chocolate, "pep" pills(aka stimulants) and energy drinks. You can read more here and here.