A single high dose of the hallucinogen psilocybin, the active ingredient in magic mushrooms, was enough to bring about a measurable personality change lasting at least a year in nearly 60 percent of the 51 participants in a new study, according to the Johns Hopkins researchers who conducted it.

Lasting change was found in the part of the personality known as openness, which includes traits related to imagination, aesthetics, feelings, abstract ideas and general broad-mindedness. Changes in these traits, measured on a widely used and scientifically validated personality inventory, were larger in magnitude than changes typically observed in healthy adults over decades of life experiences, the scientists say. Researchers in the field say that after the age of 30, personality doesn’t usually change significantly.

“Normally, if anything, openness tends to decrease as people get older,” says study leader Roland R. Griffiths, a professor of psychiatry and behavioral sciences at the Johns Hopkins University School of Medicine.

Personality was measured on a widely used and scientifically validated personality inventory, which covers openness and the other four broad domains that psychologists consider the makeup of personality: neuroticism, extroversion, agreeableness and conscientiousness. Only openness changed during the course of the study.

Griffiths says he believes psilocybin may have therapeutic uses. He is currently studying whether the hallucinogen has a use in helping cancer patients handle the depression and anxiety that comes along with a diagnosis, and whether it can help longtime cigarette smokers overcome their addiction.

“There may be applications for this we can’t even imagine at this point,” he says. “It certainly deserves to be systematically studied.”