Psilocybin, an alkaloid compound in the tryptamine family, is produced by hundreds of species of fungi and acts on the serotonin receptors in the part of the brain responsible for non-verbal imagery and emotion. Its mind-altering effects can last anywhere from three to eight hours.
It is in the same class of chemicals as mescaline, contained in the peyote cactus, which is used in religious ceremonies by Native Americans, and dimethyltryptamine, which is in ayahuasca, used by indigenous South American religions. The effects are sometimes described as similar to near-death experiences. Some research has shown that brain activity under psilocybin mimics closely that of Buddhist monks meditating.
"It appears we are hardwired with neuro-circuitry to meditate and have the spiritual experience," said Ross.
Psychologist Timothy Leary popularized hallucinogens like LSD in his 1964 book with Ralph Metzner, "The Psychedelic Experience," which he hailed as a way to "journey into new realms of consciousness."
"It opens the mind, frees the nervous system of it ordinary patterns and structures," Leary wrote.
Experiments with LSD took place as early as the late 1940s and 1950s, after it was discovered in an ergot fungus by Swiss chemist Dr. Albert Hoffman.
By 1965, more than 2,000 papers had described positive results in 40,000 patients with few side effects and a high level of safety in the treatment of psychiatric orders, depression, sexual dysfunction, bereavement and even addiction, according to the British Journal of Psychiatry.
But by 1966, the drug was made illegal after abuses by the hippie counterculture, scientists distanced themselves and the government cracked down on research licenses. By the 1970s, under pressure from the U.S. Justice Department, virtually all research ended.
"It got demonized as a most addictive drug, but the irony is that it is not addictive," said Ross. "Used in the models we describe, it can actually lead to sustained sobriety."
Volunteers in the NYU study agree to take part in two full-day sessions, seven weeks apart, where they are administered either a placebo or the psilocybin. They are monitored for anxiety and outcomes two to four weeks prior to drug administration, then one day prior, then again seven hours, one day and several weeks' intervals until 26 weeks post administration.
Investigators also measure depression, pain and quality of life as well as attitude toward their disease progression at designated intervals.
Beforehand, they undergo preparation for the experience in psychotherapy. "We take their life narrative and their cancer narrative and review all the safety parameters -- what happens if X," said Ross.
When the drug is administered, the patient is paired with a male and female therapist to monitor responses and for comfort.
"Emotional stability optimizes the chance for a good experience," said Bossis. "Trust with the monitors is crucial . If the patient doesn't feel safe, we don't go forward."
Sometimes the experience is traumatizing, but facing fears is part of the process. Doctors have an antidote to abort the experience, if necessary, or use valium to calm a patient down.