WASHINGTON The "spiritual" effects of psilocybin from so-called sacred mushrooms last for more than a year and may offer a way to help patients with fatal diseases or addictions, U.S. researchers reported on Tuesday.
The researchers also said their findings show there are safe ways to test psychoactive drugs on willing volunteers, if guidelines are followed.
In 2006, Roland Griffiths of Johns Hopkins University in Baltimore, Maryland, and colleagues gave psilocybin to 36 volunteers and asked them how it felt. Most reported having a "mystical" or "spiritual" experience and rated it positively.
More than a year later, most still said the experience increased their sense of well-being or life satisfaction, Griffiths and colleagues report in the Journal of Psychopharmacology.
"This is a truly remarkable finding," Griffiths said in a statement. "Rarely in psychological research do we see such persistently positive reports from a single event in the laboratory."
The findings may offer a way to help treat extremely anxious and depressed patients, or people with addictions, said Griffiths, whose work was funded by the U.S. National Institute on Drug Abuse.
"This gives credence to the claims that the mystical-type experiences some people have during hallucinogen sessions may help patients suffering from cancer-related anxiety or depression and may serve as a potential treatment for drug dependence," Griffiths said.
While psilocybin is widely outlawed, many U.S. states and some countries overlook its use by indigenous people in religious ceremonies.
Supervision of its use is key, the researchers noted.
"While some of our subjects reported strong fear or anxiety for a portion of their day-long psilocybin sessions, none reported any lingering harmful effects, and we didn't observe any clinical evidence of harm," Griffiths said.
Hallucinogens should not be given to people at risk for psychosis or certain other serious mental disorders, the researchers said.
But Griffiths stressed that even those who reported fear said a year later they had no permanent negative effects.
Of the volunteers who took the one-day test of psilocybin, 22 of the 36 had a "complete" mystical experience, based on a detailed questionnaire.
Griffiths said 21 continued to rate highly on this standardized scale 14 months later.
"Even at the 14-month follow-up, 58 percent of 36 volunteers rated the experience on the psilocybin session as among the five most personally meaningful experiences of their lives and 67 percent rated it among the five most spiritually significant experiences of their lives," the researchers said.
The report included some comments from the volunteers.
"Surrender is intensely powerful. To 'let go' and become enveloped in the beauty of -- in this case music -- was enormously spiritual," one volunteer said.
(Editing by Will Dunham and Vicki Allen)