maes-e.com

A third said the experience was the single most spiritually significant of their lifetimes. Many likened it to the birth of their first child or the death of a parent.

And the effects lingered.

Two months after getting the drug, 79 percent of the volunteers said they felt a moderately or greatly increased well-being or life satisfaction, according to the report published in the journal Psychopharmacology.

"Discovering how these mystical and altered consciousness states arise in the brain could have major therapeutic possibilities," said Griffiths.

These include "treatment of intolerable pain, treatment of refractory depression, amelioration of the pain and suffering of the terminally ill," he added.

Griffiths and colleagues tested 36 healthy, educated volunteers who all reported they had active spiritual lives.