[Trippy Tales: The History of 8 Hallucinogens] 
 
 But while the effects Schirp and others describe are plausible from a physiological perspective, microdosing is uncharted territory, said Matt Johnson, a psychologist at Johns Hopkins University in Baltimore, Maryland, who has studied the behavioral effects of psychedelic drugs. The drugs activate a receptor in the brain called 5HT-2A, which is most prevalent in the brain's outer layer, or cortex, in areas involved in sensation and emotion. This receptor fuels the release of the "feel-good" brain chemical, serotonin, which creates a domino effect in the brain that leads to many other brain changes. According to the video, if you were to take the same dose of the drug three days in a row, the third day that dosage would have little to no effect. Follow Tanya Lewis on Twitterand Google+. Follow Live Science @livescience, Facebook & Google+. Original article on Live Science.
– Some users of LSD like taking tiny amounts of the hallucinogenic drug—often by drinking acid-laced water—to experience subtle benefits like increased focus, creativity, or friendliness toward people, LiveScience reports. "It's like the coffee to wake up the mind-body connection," says former poker player Martijn Schirp, who now writes for HighExistence.com. "When I notice it is working, depending on the dosage, time seems to be slowing down a bit, everything seems covered with a layer of extra significance." Schirp says he embraced the practice, called "microdosing," because it gave him a chance "to get a taste of this without [the experience] completely overwhelming me." But any possible long-term risks are unknown because, as Medical Daily notes, LSD remains an illegal drug that's rarely tested. "The unintended consequence is they've really impeded research and development," a psychopharmacologist told LiveScience a couple of years ago. "We cannot understand the brain if we're not studying drugs." According to one psychologist, LSD does mimic antidepressants like Prozac by freeing up the brain's "feel-good" chemical, serotonin, so microdosing may work as advertised. It's been around for years, too: LSD inventor Albert Hofmann microdosed in his old age, and the practice is described in James Fadiman's 2011 book The Psychedelic Explorer's Guide. Yet even Schirp admits it's not always positive: "At times, the experience was still too overwhelming to be productive—I just wanted to lay down or take a walk," he says. (Recent studies on psychedelic drugs downplay the risk of psychosis and note possible anti-depressant effects.)