Among scientists, there are tentative signs of a psychedelics renaissance. After decades of stigma, impressive research is showing the power of these substances to help sufferers of depression and addiction, or to comfort patients with a terminal cancer diagnosis, struggling to face their own end. This is the fascinating territory that the journalist Michael Pollan explores with his new book, “How to Change Your Mind.” Pollan dives into brain science, the history of psychedelics (and our tortured attitudes towards them) but his larger subject is the nature of human consciousness. Eventually Pollan decides to try psychedelics himself — and documents, beautifully, a number meaningful experiences and the way his own mind has changed. He answered questions from Mind Matters editor Gareth Cook.

How did you get interested in writing about this topic, after all of your work on food?

It’s true I’m best known for my books about food and agriculture, but that work grew out of a deeper fascination with the human engagement with the natural world, and the species we co-evolved with, a fascination I explored in earlier books like The Botany of Desire and Second Nature. Food and beauty are two of the human desires other species have evolved to gratify, but there are other, more mysterious desires, and the human drive to change consciousness, whether mildly and routinely with plant drugs such as caffeine, or more dramatically with psychoactive mushrooms, has always fascinated me. Why do we want to do this potentially risky thing, and why did plants and fungi evolve these remarkable chemicals that affect us in this way? What do these experiences do for us, as individuals or as a society? Psychedelics are the most extreme case of this curious phenomenon, and they have been a central part of human societies for thousands of years. I wanted to find out why.

And then I began hearing about a renaissance of research into psychedelics by scientists hoping to treat cancer patients suffering from “existential distress,” addicts, people struggling with depression and so-called “healthy normals.” These researchers had found that psilocybin, the psychoactive compound in magic mushrooms, could reliably occasion a “mystical experience” in people that they deemed one of the two or three most significant experiences in their lives—comparable to the birth of a child or death of a parent. The experience had changed them in lasting ways. This was something I needed to explore. I wasn’t sure I had ever had a spiritual experience. Would one happen to me? Was there some dimension of existence or consciousness I was missing out on? Was it really possibly to change one’s mind as an adult? My journalistic curiosity soon morphed into a personal quest to explore some of the uncharted territory of both the mind and my mind.

Can you explain what the “default mode network” is, and how it figures in your story?

One of the most interesting early findings of recent psychedelic research is that activity in the “default mode network” falls off sharply during the psychedelic experience. This network is a critical hub in the brain that links parts of the cerebral cortex to deeper and older structures involved in memory and emotion. The DMN appears to be involved in a range of “metacognitive” functions such as a self-reflection; mental time travel; theory of mind (the ability to imagine the mental states of other people) and the creation of the so-called “autobiographical self”—the process of weaving what happens to us into the narrative of who we are, thereby giving us a sense of a self that endures over time. (Curiously, fMRI’s of the brains of experienced meditators shows a pattern of activity, or quieting of activity, very similar to that of people who have been given psilocybin.) When the default mode network is taken offline by a psychedelic, not only do we experience a loss of the sense of having a self, but myriad new connections among other brain regions and networks spring up, connections that may manifest in mental experience as hallucination (when, say, your emotion centers talk directly to your visual cortex), synesthesia (as when you can see sound or hear flavors) or, possibly, fresh perspectives and metaphors. Disturbing a complex system is a great way to force it to reveal its secrets—think of a particle accelerator—and psychedelics allows us to do that to normal ego-centered consciousness.

You tried psychedelic drugs as a part of your work on this book, and I wonder which of those experiences most changed you?

After interviewing dozens of volunteers who had had guided psychedelic trips I became so curious that I decided to have one (actually several) myself. I think the most transformative of these was a guided trip on psilocybin, during which I experienced the complete dissolution of my ego—I could see the entity formerly understood as me “out there” spread over the landscape like a coat of paint. Yet there was still some recording “I” taking in the scene, a sort of disembodied, dispassionate awareness. Though temporary, that perspective was transformative. It suggested to me that I wasn’t necessarily identical to my ego, that there was potentially another ground on which to plant my feet. In subtle ways this has changed my relationship to my ego, which I no longer regard as identical to me, odd as that sounds, but as a kind of useful though sometimes neurotic and annoying character who occasionally needs to be put in his place. Sometimes when I’m reacting to an event or comment I can catch myself before the usual defenses leap into action, because I can see what he’s up to and why. This is the sort of perspective you can occasionally develop with years of meditation or psychoanalysis; psilocybin gave it to me in an afternoon.

What do you wish the general public understood about psychedelic drugs and their potential?

The image of psychedelics in the public mind has been substantially shaped by the Sixties counterculture and Timothy Leary, but that is just one brief chapter in a much longer and more interesting history reaching back thousands of years, one in which these drugs were the subject of serious research and, long before that, carefully regulated use, usually in a ritual context. These remarkable molecules have the potential—and I stress “potential,” because much more research needs to be done—to relieve the suffering of millions of people struggling with depression, anxiety, obsession, addiction and the fear of death. Many of the researchers involved believe we could be on the verge of a revolution in mental health care, which is a segment of medicine that right now has very little to offer and is dire need of some new thinking and new tools. The drugs can be used carelessly, as they often were in the sixties, but in the proper hands, they can heal and illuminate the mind.