The research subject, a woman in her 60s, reported a blinding light that flooded her consciousness, a luminosity she interpreted as an emanation from God, an invitation to the heavens. “I felt a sense of joyous expansion as it opened fully to me, like entering a splendid palace, yet the feeling was completely natural and gentle,” she wrote. Months later, others who took part in the research study ranked it as one of the five most important experiences of their lives. The visual clarity and well-being they felt, mixed with a sense of the mystical feeling that all things are interconnected, came from a high dose of psilocybin, known on the street as magic mushrooms.

When Roland Griffiths, a professor of psychiatry and behavioral sciences at the School of Medicine, unveiled results of that study in 2006, his team was investigating whether the ostensibly spiritual experiences that psilocybin users report could provide clues to how the brain works. But in doing so, the researchers ripped the lid off an area of inquiry that had been in place for more than 30 years, and reintroduced an illicit drug to the rigors of medical research.

Griffiths’ research into the pharmacological value of psilocybin continues. He has also turned his sights to another recreational drug that may have medicinal properties. Intrigued by a darkly understood set of receptors in the brain, Griffiths and Matthew Johnson, an assistant professor of psychiatry and behavioral sciences, decided to study Salvia divinorum, a smoked drug that is legally sold for $20 to $40 in head shops. Known on the street as salvia, the drug has garnered headlines because of a YouTube video of one of its addled users, teen star Miley Cyrus, and news accounts reporting that Jared Loughner, the alleged gunman who in January killed six people and wounded 13, including a congresswoman, had regularly used it. Griffiths doesn’t condone its use, or argue whether it should be made illegal or not (it currently isn’t in most places). But he says salvia’s ability to activate kappa opioid receptors in the brain makes it worthy of study.

The results, published in the online journal Drug and Alcohol Dependence, found that whereas salvinorin A, salvia’s active ingredient, can be intensely disorienting shortly after it is smoked, it has no other adverse side effects in the short term, meaning that it might prove useful for scientific inquiry. “It gives us another window to look through,” he says. “It doesn’t appear to be addictive, which is a real advantage if you’re trying to find drugs that work in the brain to cure disease, or designing studies that involve human subjects.” The substance targets regions in the brain that are believed to trigger depression when activated. Understanding how this happens can lead to drugs to control the manic phase of manic depression, Griffiths says. Setting the kappa receptors in motion may also eliminate pain, which could lead to development of a new class of analgesics and possibly to advances in treatments for Alzheimer’s disease.

Griffiths is interested in mind-altering drugs for what they can teach about the brain. “We want to find out what triggers addiction and which substances are most likely to be abused,” he says. “Those are important con­siderations in drug development.”

But it was more than science that moved Griffiths to test the psychotropic properties of a humble mushroom more than a decade ago. His metamorphosis began when a friend joined a meditation group 15 years ago. “I was intrigued by the idea of turning the mind toward the deeper self,” says Griffiths. “That thought was quite a departure for me. I was a radical behaviorist at the time. I had been trained not to take what people were feeling seriously.” He went along for the ride, in search of “the nature of spiritual, mystical experience,” and began a regimen of mantra-based Indian meditation. Since then, he’s explored several other types of so-called mindfulness, and spent a week in retreat with others as recently as December. Early on in the course of his meditation journey, he says, “I was introduced to literature on psilocybin and psychedelic substances.”

But those studies weren’t exactly current. During the 1960s, when Timothy Leary, a Harvard psychology professor, had exhorted young people to “turn on, tune in, drop out” with the help of hallucinogenic substances, he played a role in turning off studies of those substances. Highly publicized deaths from all types of drugs made lab work that utilized hallucinogens appear chancy or unethical. Among the drug casualties were LSD, DPT, and psilocybin, all banned by the federal Controlled Substances Act of 1970.

“A whole generation of researchers was effectively marginalized,” says Griffiths. “There were many who had been discovering that people who were undergoing some kind of mystical experience on these hallucinogens had the potential to have profound and positive mood and behavior changes.” Now, in part because of Griffiths’ use of hallucination-inducing substances as subjects of inquiry, researchers at New York University, at UCLA, in Great Britain, and elsewhere have reintroduced illicit drugs to their laboratories. He’d like to add more to his roster of ongoing studies, but he and other researchers are hamstrung by a lack of funding. Despite the much-lauded findings on psilocybin, getting government approval for studies is still difficult.

Griffiths argues that there is too much value in those studies for governments and, possibly, drug manufacturers to ignore. “Scientifically, there’s a lot to get at. We’ve known that primary mystical experiences from hallucinogenic substances have been around for thousands of years. But it’s never really been studied. Now, we can unpack those experiences using functional magnetic resonance imaging and genetics to see how some people are predisposed to such experiences and what that may mean for developing new treatments.” What’s more, people who suffer from mental illnesses and others that affect the nervous system shouldn’t have to wait longer than they have to for answers, which may come from investigations of substances that have been pariahs for decades, he believes: “It’s far too important not to do this.”