Several major universities are now trying to unravel the mysteries of hallucinogens. Roland Griffiths, a professor in the departments of psychiatry and neuroscience at Johns Hopkins University—and one of the first to resume work on these drugs—published a study five years ago that demonstrated how effective they are at improving how a person feels. "That first study blew me away," he says. "Nearly all the participants reported significant positive changes in attitude and behavior, and those changes were also observed by the participants’ friends, family, and colleagues. It was remarkable."