A new study has revealed that the spiritual effects of magic mushrooms can last for many months.
Researchers at Johns Hopkins University in Maryland found that the majority of 36 volunteers who took psilocybin in controlled conditions continued to feel the beneficial effects for more than a year afterwards.
"Most of the volunteers looked back on their experience up to 14 months later and rated it as the most, or one of the five most, personally meaningful and spiritually significant of their lives," said Roland Griffiths, a professor in the department of Psychiatry and Behavioral Sciences and Neuroscience.
The first results of the clinical trial, aimed at uncovering the secrets of the "magic" mushrooms that have been used for religious or healing purposes in some cultures for centuries, were published in 2006.
Fourteen months after the trial, the 36 volunteers -- all in good physical and mental health -- were given the same questionnaire as well as some follow-up questions.
Results show that about the same proportion ranked their experience in the trial as one of the most personally meangingful or spiritually significant events of their lives.
"This is a truly remarkable finding," said Griffiths, lead author of the study which appeared in the Journal of Psychopharmacology.
"Rarely in psychological research do we see such persistently positive reports from a single event in the laboratory."
He said the results gave credence to claims that the mystical-type experiences some people had during hallucinogen sessions may help patients suffering from cancer-related anxiety or depression.
Psilocybin could also be used as a possible treatment for drug dependance, the professor said.
He said his team was "eager" to continue their research, adding that although some of the volunteers had reported fear and anxiety immediately after receiving psilocybin, "none reported any lingering harmful effects."
However, the team warned against giving hallucinogens to people at risk of psychosis or other serious mental disorders, and said it was important that it be administered under controlled conditions.
Psilocybin is a plant alkaloid that affects some of the same brain receptors as serotonin, a neurotransmitter.