A new study shows that only one dose of hallucinogenic mushrooms can change a person’s personality for more than a year and possibly permanently.

People who took psilocybin, a compound in the “magic mushroom” that causes hallucinations and feelings of highness, showed a more open personality after their experience, an effect that lasted for at least 14 months. Openness is a psychological term that denotes appreciation for new experiences. More open people tend to have wide imagination and assess feelings, art and curiosity.

Researcher Katherine MacLean said that this character distortion is unusual, because the character rarely changes after the age of 25 or 30 years (in fact, a recent study has found that our characters are largely set to life since 1999).

“This is one of the first studies to show that you can really change the characters of adults,” said MacLean, a postdoctoral researcher at Johns Hopkins University School of Medicine.

McLean told LiveScience that the root of the change does not seem to be the drug itself, but the mystical experiences often raised by psilocybin. She said that these deep transcendent feelings do not feel less real for people because they are chemically induced.

“After so many years, people say it was one of the most profound experiences of their lives,” said McLean. “If you think about it in this context, it’s not surprising that this always is.”

After so many years, people say it was one of the most profound experiences of their lives Dr. Edward Boone

Research on hallucinogens is usually associated with 1960s counter-culture figures such as Ken Casey and his “acid test” parties fueled by LSD. But over the past decade, a bleak gradual approach has emerged to study the effect of hallucinogens, says McLean. Experiments are tightly controlled – it is not easy to obtain permission to give volunteers illegal drugs – but they reveal that the materials associated with the party of the dead more grateful than the psychiatrist’s office may have medical uses after all.

In Massachusetts, the nonprofit Research Institute (MAPS), or the Interdisciplinary Association for Anesthetic Studies, is looking into the possibility of using the hallucinogenic MDMA drug to treat PTSD. Both LSD and psilocybin are under investigation for use in treating anxiety; a McClain post-doctoral advisor at Johns Hopkins University, Roland Griffiths, is leading a study to see if psilocybin may relieve anxiety and depression in cancer patients. Other Griffith studies focus on the use of psilocybin to break nicotine addiction.

In the current study, McLean and her colleagues looked at questionnaires from 51 people who took psilocybin as part of two separate studies by John Hopkins. The volunteers were all new to hallucinogenic drugs.

Each person attended between two and five hours of drug sessions for eight hours as they were sitting blindfolded on the sofa listening to music – a way to encourage introspection. During one session, the volunteers received a moderate to high dose of psilocybin, but neither they nor the experimenters knew whether to swallow a psilocybin or placebo on any given day.

In one experiment, the participants came to the lab twice. On one visit, they were given the real deal and again got Ritalin, which simulates the side effects of psilocybin without hallucinations.

In another experiment, during a five-session session, participants received either placebo or one of varying doses of the drug. For the purposes of this study, the researchers focused on a high dose session, which was the same dose that was given during the first experiment.

The results, published in the Journal of Psychopharmacology, revealed that while other aspects of the character remained unchanged, openness increased after the experience of psilocybin. The effect was especially permanent for those who reported a “mystical” experience with their dose. These mystical experiences, MacLean said, were characterized by a feeling of deep connectedness, along with feelings of joy, veneration and peace. [Top 10 Secrets of Mind]

“It is possible that not only will psilocybin cause changes like this, but more than these kinds of profound, life-changing experiences, whatever flavor they take,” she said. “For many people, psilocybin allows them to bypass their thinking about the world.”

MacLean said that about 30 of the 51 volunteers had an internal experience. The changes in openness in these participants were greater than those that have been commonly seen over decades of adult life experience.

But the experiment is very accurate, McLean warned.