Forty-five years after Timothy Leary, the apostle of drug-induced mysticism, urged his hippie followers to "turn on, tune in and drop out", researchers have found that magic mushrooms do change a user's personality – for the better.

The fungi have long been known for their psychedelic effects, but far from damaging the brain, the hallucinogenic drug they contain enhances feelings and aesthetic sensibilities, scientists say. The study, at Johns Hopkins University of Medicine in Baltimore, found that a single dose of psilocybin, the active ingredient in magic mushrooms, was enough to cause positive effects for up to a year. "Psilocybin can facilitate experiences that change how people perceive themselves and their environment," said Roland Griffiths, a study author and professor of psychiatry and behavioural science at Johns Hopkins. "That's unprecedented."

Users who had a "mystical experience" while taking the drug showed increases in a personality trait dubbed "openness", one of the five major traits used in psychology to describe human personality. Openness is associated with imagination, artistic appreciation, feelings, abstract ideas and general broad-mindedness. None of the other four traits – extroversion, neuroticism, agreeableness and conscientiousness – was altered.

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Under controlled scientific conditions, researchers gave 51 adults either psilocybin or a placebo in up to five eight-hour sessions. They were told to lie on a sofa with their eyes covered and listen to music while focusing on an "inner experience".

Their personalities were screened after each drug session and also about a year later. Of the 51, 30 had a mystical experience, after which their openness scores rose, and remained higher for up to a year after the tests. The 21 who did not have a mystical experience showed no change.