How to Change Your Mind: The New Science of Psychedelics

by Michael Pollan

Brian Turner, who at the time of his journey was a forty-four-year-old physicist working for a military contractor (with a security clearance), put it this way: I could feel my body dissolving, beginning with my feet, until it all disappeared but the left side of my jaw. It was really unpleasant; I could count only a few teeth left and the bottom part of my jaw. I knew that if that went away I would be gone. Then I remembered what they told me, that whenever you encounter anything scary, go toward it. So instead of being afraid of dying I got curious about what was going on. I was no longer trying to avoid dying. Instead of recoiling from the experience, I began to interrogate it. And with that, the whole situation dissolved into this pleasant floaty feeling, and I became the music for a while. Soon after, he found himself “in a large cave where all my past relationships were hanging down as icicles: the person who sat next to me in second grade, high school friends, my first girlfriend, all of them were there, encased in ice. It was very cool. I thought about each of them in turn, remembering everything about our relationship. It was a review—something about the trajectory of my life. All these people had made me what I had become.”

Amy Charnay, a nutritionist and herbalist in her thirties, came to Hopkins after a crisis. An avid runner, she had been studying forest ecology when she fell from a tree and shattered her ankle, ending both her running and her forestry careers. In the early moments of her journey, Amy was overcome by waves of guilt and fear. “The visual I had was from the 1800s and I was up on this stage. Two people next to me were slipping a noose around my neck while a crowd of people watched, cheering for my death. I felt drenched with guilt, just terrified. I was in a hell realm. And I remember Bill asking, ‘What’s going on?’ “ ‘I’m experiencing a lot of guilt.’ Bill replied, ‘That’s a very common human experience,’ and with that, the whole image of being hanged pixilated and then just disappeared, to be replaced by this tremendous sensation of freedom and interconnectedness. This was huge for me. I saw that if I can name and admit a feeling, confess it to someone, it would let go. A little older and wiser, now I can do this for myself.”

And I remember repeating to myself again and again, “Nothing matters, nothing matters any more. I see the point! Nothing matters at all.” And then it was over. During the last few hours, reality began slowly, effortlessly, to stitch itself back together. In sync with some particularly wowing choral music, I had an incredibly moving sense of triumphant reawakening, as if a new day were dawning after a long and harrowing night.

At the same time I was interviewing Richard Boothby and his fellow volunteers, I was reading William James’s account of mystical consciousness in The Varieties of Religious Experience in the hope of orienting myself. And indeed much of what James had to say helped me get my bearings amid the torrent of words and images I was collecting. James prefaced his discussion of mystical states of consciousness by admitting that “my own constitution shuts me out from their enjoyment almost entirely.” Almost entirely: what James knows about mystical states was gleaned not just from his reading but also from his own experiments with drugs, including nitrous oxide.

The noetic quality is James’s second mark: “Mystical states seem to those who experience them to be also states of knowledge … They are illuminations, revelations full of significance and importance … and as a rule they carry with them a curious sense of authority.”

felt like mysteries were being unveiled and yet it all felt familiar and more like I was being reminded of things I had already known. I had a sense of initiation into dimensions of existence most people never know exist, including the distinct sense that death was illusory, in the sense that it is a door we walk through into another plane of existence, that we’re sprung from an eternity to which we will return.

All the same, the basic insights afforded to me during the session still seem for the most part compelling. What was the philosophy professor’s compelling insight? “Love conquers all.”

‘I’ve heard that said all my life,’ we exclaim, ‘but I never realized its full meaning until now.’ ” The mystical journey seems to offer a graduate education in the obvious. Yet people come out of the experience understanding these platitudes in a new way; what was merely known is now felt, takes on the authority of a deeply rooted conviction. And, more often than not, that conviction concerns the supreme importance of love.

Karin Sokel, a life coach and energy healer in her fifties, described an experience “that changed everything and opened me profoundly.” At the climax of her journey, she had an encounter with a god who called himself “I Am.” In its presence, she recalled, “every one of my chakras was exploding. And then there was this light, it was the pure light of love and divinity, and it was with me and no words were needed. I was in the presence of this absolute pure divine love and I was merging with it, in this explosion of energy … Just talking about it my fingers are getting electric. It sort of penetrated me. The core of our being, I now knew, is love. At the peak of the experience, I was literally holding the face of Osama bin Laden, looking into his eyes, feeling pure love from him and giving it to him. The core is not evil, it is love. I had the same experience with Hitler, and then someone from North Korea. So I think we are divine. This is not intellectual, this is a core knowingness.”

I asked Sokel what made her so sure this wasn’t a dream or drug-induced fantasy—a suggestion that proved no match for her noetic sense. “This was no dream. This was as real as you and I having this conversation. I wouldn’t have understood it either if I hadn’t had the direct experi...

This last point James alludes to in his discussion of the third mark of mystical consciousness, which is “transiency.” For although the mystical state cannot be sustained for long, its traces persist and recur, “and from one recurrence to another it is susceptible of c...

For most of the Hopkins volunteers I interviewed, their psilocybin journeys had taken place ten or fifteen years earlier, and yet their effects were still keenly felt, in some cases on a daily basis. “Psilocybin awakened my loving compassion and gratitude in a way I had never experienced before,” a psychologist who asked not to be named told me when I asked her about lasting effects. “Trust, Letting go, Openness, and Being were the touchstones of the experience for me. Now I know these things instead of just believing.” She had turned Bill Richards’s flight instructions into a manual for living.

Hayes particularly recommends the experience to people in middle age for whom, as Carl Jung suggested, experience of the numinous can help them negotiate the second half of their lives. Hayes added, “I would not recommend it to young people.”

Charnay’s journey at Hopkins solidified her commitment to herbal medicine (she now works for a supplement maker in Northern California); it also confirmed her in a decision to divorce her husband. “Everything was now so clear to me. I came out of the session, and my husband was late to pick me up. I realized, this is the theme with us. We’re just really different people. I just got my ass kicked today, and I needed him to be on time.” She broke the news to him in the car going home and has not looked back.

To listen to these people describe the changes in their lives inspired by their psilocybin journeys is to wonder if the Hopkins session room isn’t a kind of “human transformation factory,” as Mary Cosimano, the guide who has probably spent more time there than anyone else, described it to me. “From now on,” one volunteer told me, “I think of my life as before and after psilocybin.” Soon after his psilocybin experience, Brian Turner, the physicist, quit his job with the military contractor and moved to Colorado to study Zen. He had had a meditation practice before psilocybin, but “now I had the motivation, because I had tas...

Turner is now an ordained Zen monk, yet he is also still a physicist, working for a company that makes helium neon lasers. I asked him if he felt any tension between his science and his spiritual practice. “I don’t feel there’s a contradiction. Yet what happened at Hopkins has influenced my physics. I realize there are just some domains that science will not penetrate. Science can bring you to t...

psilocybin experience had led to lasting changes in their personalities. Specifically, those volunteers who had “complete mystical experiences” (as determined by their scores on the Pahnke-Richards Mystical Experience Questionnaire) showed, in addition to lasting improvements in well-being, long-term increases in the personality trait of “openness to experience.” One of the five traits psychologists use to assess personality (the other four are conscientiousness, extroversion, agreeableness, and neuroticism), openness encompasses aesthetic appreciation and sensitivity, fantasy and imagination, as well as tolerance of others’ viewpoints and values; it also predicts creativity in both the arts and the sciences, as well as, presumably, a willingness to entertain ideas at odds with those of current science. Such pronounced and lasting changes in the personalities of adults are rare.

Griffiths mentioned a colleague at Hopkins, a prominent psychiatrist named Paul McHugh, who dismisses the psychedelic experience as nothing more than a form of “toxic delirium.” He encouraged me to google McHugh.

Griffiths admits it is possible that what he’s seeing is some form of temporary psychosis, and he plans to test for delirium in an upcoming experiment, but he seriously doubts that diagnosis accurately describes what is going on with his volunteers. “Patients suffering from delirium find it really unpleasant,” he points out, “and they certainly don’t report months later, ‘Wow, that was one of the greatest and most meaningful experiences of my life.’ ”

When Paul was fourteen, John told him about magic mushrooms, and when he went off to Yale, John left behind a book, Altered States of Consciousness, that made a tremendous impression on Paul. Edited by Charles T. Tart, a psychologist, the book is a doorstop of an anthology of scholarly writings about non-ordinary mental states, covering the spectrum from dreaming and hypnosis to meditation and psychedelics.

But the reason the book made such a lasting impression on Stamets had less to do with its contents, provocative as these were, than with the reaction the book elicited in certain adults. “My friend Ryan Snyder wanted to borrow it. His parents were really conservative. A week later, when I told him I wanted it back, he stalls and delays. Another week goes by, I ask him again, and he finally confesses what happened. ‘My parents found it and they burned it.’ “They burned my book?!? That was a pivotal moment for me. I saw the Snyders as the enemy, trying to suppress the exploration of consciousness. But if this was such powerful information that they felt compelled to destroy it, then this was powerful information I now had to have. So I owe them a debt of gratitude.”

Stamets went off to Kenyon College, where, as a freshman, he had “a profound psychedelic experience” that set his course in life. As long as he could remember, Stamets had been stymied by a debilitating stutter. “This was a huge issue for me. I was always looking down at the ground because I was afraid people would try to speak to me. In fact, one of the reasons I got so good at finding mushrooms was because I was always looking down.” One spring afternoon toward the end of his freshman year, walking alone along the wooded ridgeline above campus, Stamets ate a whole bag of mushrooms, perhaps ten grams, thinking that was a proper dose. (Four grams is a lot.) As the psilocybin was coming on, Stamets spied a particularly beautiful oak tree and decided he would climb it. “As I’m climbing the tree, I’m literally getting higher as I’m climbing higher.” Just then the sky begins to darken, and a thunderstorm lights up the horizon. The wind surges as the storm approaches, and the tree begins to sway. “I’m getting vertigo but I can’t climb down, I’m too high, so I just wrapped my arms around the tree and held on, hugging it tightly. The tree became the axis mundi, rooting me to the earth....

The Spanish sought to crush the mushroom cults, viewing them, rightly, as a mortal threat to the authority of the church.

“The visions were not blurred or uncertain,” he writes. Indeed, “they seemed more real to me than anything I had ever seen with my own eyes.” At this point, the reader begins to feel the literary hand of Aldous Huxley exerting a certain pressure on both Wasson’s prose and his perceptions: “I felt that I was now seeing plain, whereas ordinary vision gives us an imperfect view.” Wasson’s own doors of perception had been flung wide open: “I was seeing the archetypes, the Platonic ideas, that underlie the imperfect images of everyday life.” To read Wasson is to feel as if you were witnessing the still-fresh and malleable conventions of the psychedelic narrative gradually solidifying before your eyes. Whether Aldous Huxley invented these tropes, or was merely their stenographer, is hard to say, but they would inform the genre, as well as the experience, from here on. “For the first time the word ecstasy took on real meaning,” Wasson recalls. “For the first time it did not mean someone else’s state of mind.” Wasson concluded from his experience that his working hypothesis about the roots of the religious experience in psychoactive fungi had been vindicated. “In man’s evolutionary past … there must have come a moment in time when he discovered the secret of the hallucinatory mushrooms. Their effect on him, as I see it, could only have been profound, a detonator to new ideas. For the mushrooms revealed to him worlds beyond the horizons known to him, in space and time, even worlds ...

Shortly after the article in Life was published, Wasson arranged to have some specimens of the Mexican mushrooms sent to Albert Hofmann in Switzerland for analysis. In 1958, Hofmann isolated and named the two psychoactive compounds, psilocybin and psilocin, and developed the synthetic version of psilocybin used in the current research. Hofmann also experimented with the mushrooms himself. “Thirty minutes after my taking the mushrooms,” he wrote, “the exterior world began to undergo a strange transformation. Everything assumed a Mexican character.” In 1962, Hofmann joined Wasson on one of his return trips to Huautla, during which the chemist gave María Sabina psilocybin in pill form. She took two of the pills and declared they did indeed contain the spirit of the mushroom.fn7 It didn’t take long for thousands of other people—including, eventually, celebrities such as Bob Dylan, John Lennon, and Mick Jagger—to find their way to Huautla and to María Sabina’s door.fn8

For María Sabina and her village, the attention was ruinous. Wasson would later hold himself responsible for “unleash[ing] on lovely Huautla a torrent of commercial exploitation of the vilest kind,” as he wrote in a plaintive 1970 New York Times op-ed. Huautla had become first a beatnik, then a hippie mecca, and the sacred mushrooms, once a closely guarded secret, were now being sold openly on the street. María Sabina’s neighbors blamed her for what was happening to their village; her home was burned down, and she was briefly jailed. Nearing the end of her life, she had nothing but regret for having shared the divine mushrooms with R. Gordon Wasson and, in turn, the world. “From the moment the foreigners arrived,” she told a visitor, “the saint children lost their purity. They lost their force; the foreigners spoiled them. From now on they won’t be any good.”

This brings us to Terence McKenna’s stoned ape theory, the epitome of all mycocentric speculation, which Stamets had wanted to make sure we discussed. Though reading is no substitute for hearing McKenna expound his thesis (you can find him on YouTube), he summarizes it in Food of the Gods (1992): Psilocybes gave our hominid ancestors “access to realms of supernatural power,” “catalyzed the emergence of human self-reflection,” and “brought us out of the animal mind and into the world of articulated speech and imagination.” This last hypothesis about the invention of language turns on the concept of synesthesia, the conflation of the senses that psychedelics are known to induce: under the influence of psilocybin, numbers can take on colors, colors attach to sounds, and so on. Language, he contends, represents a special case of synesthesia, in which otherwise meaningless sounds become linked to concepts. Hence, the stoned ape: by giving us the gifts of language and self-reflection psilocybin mushrooms made us who we are, transforming our primate ancestors into Homo sapiens.

Eaten in small doses, psychedelic mushrooms might well increase fitness in animals, by increasing sensory acuity and possibly focus as well. A 2015 review article in the Journal of Ethnopharmacology reported that several tribes around the world feed psychoactive plants to their dogs in order to improve their hunting ability.fn9 At higher doses, however, one would think that animals tripping on psychedelic mushrooms would be at a distinct disadvantage for survival, and no doubt many of them are. But for a select few, the effects may offer some adaptive value, not only for themselves, but also possibly for the group and even the species.

In a book called Animals and Psychedelics: The Natural World and the Instinct to Alter Consciousness, Samorini hypothesizes that during times of rapid environmental change or crisis it may avail the survival of a group when a few of its members abandon their accustomed conditioned responses and experiment with some radically new and different behaviors. Much like genetic mutations, most of these novelties will prove disastrous and be discarded by natural selection. But the laws of probability suggest that a few of the novel behaviors might end up being useful, helping the individual, the group, and possibly the species to adapt to rapid changes in their environment. Samorini calls this a “depatterning factor.” There are times in the evolution of a species when the old patterns no longer avail, and the radical, potentially innovative perceptions and behaviors that psychedelics sometimes inspire may offer the best chance for adaptation. Think of it as a neurochemically induced source of variation in a population.

It is difficult to read about Samorini’s lovely theory without thinking about our own species and the challenging circumstances in which we find ourselves today. Homo sapiens might have arrived at one of those periods of crisis that calls for some mental and behavioral depatterning. Could that be why nature has sent us these psychedelic molecules now?

Stamets dilated on the idea of psilocybin as a chemical messenger sent from Earth, and how we had been elected, by virtue of the gift of consciousness and language, to hear its call and act before it’s too late. “Plants and mushrooms have intelligence, and they want us to take care of the environment, and so they communicate that to us in a way we can understand.” Why us? “We humans are the most populous bipedal organisms walking around, so some plants and fungi are especially interested in enlisting our support. I think they have a consciousness and are constantly trying to direct our evolution by speaking out to us biochemically. We just need to be better listeners.” These were riffs I’d heard Stamets deliver in countless talks and interviews. “Mushrooms have taught me the interconnectedness of all life-forms and the molecular matrix that we share,” he explains in another one. “I no longer feel that I am in this envelope of a human life called Paul Stamets. I am part of the stream of molecules that are flowing through nature. I am given a voice, given consciousness for a time, but I feel that I am part of this continuum of stardust into which I am born and to which I will return at the end of this life.” Stamets sounded very much like the volunteers I met at Hopkins who had had full-blown mystical experiences, people whose sense of themselves as individuals had been subsumed into a larger whole—a form of “unitive consciousness,” which, in Stamets’s case, had folded him i...

It seemed to me these were the most beautiful leaves I had ever seen. It was as if they were emitting their own soft green glow. And it felt like a kind of privilege to gaze out at the world through their eyes, as it were, as the leaves drank up the last draughts of sunlight, transforming those photons into new matter. A plant’s-eye view of the world—it was that, and for real! But the leaves were also looking back at me, fixing me with this utterly benign gaze. I could feel their curiosity and what I was certain was an attitude of utter benevolence toward me and my kind.

supernatural about my heightened perceptions that afternoon, nothing that I needed an idea of magic or a divinity to explain. No, all it took was another perceptual slant on the same old reality, a lens or mode of consciousness that invented nothing but merely (merely!) italicized the prose of ordinary experience, disclosing the wonder that is always there in a garden or wood, hidden in plain sight—another form of consciousness “parted from [us],” as William James put it, “by the filmiest of screens.” Nature does in fact teem with subjectivities—call them spirits if you like—other than our own; it is only the human ego, with its imagined monopoly on subjectivity, that keeps us from recognizing them all, our kith and kin. In this sense, I guess Paul Stamets is right to think the mushrooms are bringing us messages from nature, or at least helping us to open up and read them.

Maybe to be in a garden and feel awe, or wonder, in the presence of an astonishing mystery, is nothing more than a recovery of a misplaced perspective, perhaps the child’s-eye view; maybe we regain it by means of a neurochemical change that disables the filters (of convention, of ego) that prevent us in ordinary hours from seeing what is, like those lovely leaves, staring us in the face. I don’t know. But if those dried-up little scraps of fungus taught me anything, it is that there are other, stranger forms of consciousness available to us, and, whatever they mean, their very existence, to quote William James again, “forbid[s] a premature closing of our accounts with reality.”

Stephen Ross is one such researcher. A psychiatrist specializing in addiction at Bellevue, he directed an NYU trial using psilocybin to treat the existential distress of cancer patients, to which I will return later; since then, he has turned to the treatment of alcoholics with psychedelics, what had been perhaps the single most promising area of clinical research in the 1950s. When several years ago an NYU colleague mentioned to Ross that LSD had once been used to treat thousands of alcoholics in Canada and the United States (and that Bill Wilson, the founder of Alcoholics Anonymous, had sought to introduce LSD therapy into AA in the 1950s), Ross, who was in his thirties at the time, did some research and was “flabbergasted” by all that he—as an expert on the treatment of alcoholism—did not know and hadn’t been told. His own field had a secret history.

“I felt a little like an archaeologist, unearthing a completely buried body of knowledge. Beginning in the early fifties, psychedelics had been used to treat a whole host of conditions,” including addiction, depression, obsessive-compulsive disorder, schizophrenia, autism, and end-of-life anxiety.

“There had been forty thousand research participants and more than a thousand clinical papers! The American Psychiatric Association had whole meetings centered around LSD, this new wonder drug.” In fact, there were six international scientific meetings devoted to psychedelics between 1950 and 1965. “Some of the best minds in psychiatry had seriously studied these compounds in therapeutic models, with government funding.” But after the culture and the psychiatric establishment turned against psychedelics in the mid-1960s, an entire body of knowledge was effectively erased from the fie...

As the literary theorists would say, the psychedelic experience is highly “constructed.” If you are told you will have a spiritual experience, chances are pretty good that you will, and, likewise, if you are told the drug may drive you temporarily insane, or acquaint you with the collective unconscious, or help you access “cosmic consciousness,” or revisit the trauma of your birth, you stand a good chance of having exactly that kind of experience.

Psychologists call these self-fulfilling prophecies “expectancy effects,” and they turn out to be especially powerful in the case of psychedelics.

Another challenge was the irrational exuberance that seemed to infect any researchers who got involved with LSD, an enthusiasm that might have improved the results of their experiments at the same time it fueled the skepticism of colleagues who remained psychedelic virgins.

Humphry Osmond wrote that the extraordinary promise of LSD was to allow the therapist who took it to “enter the illness and see with a madman’s eyes, hear with his ears, and feel with his skin.”

LSD research would eventually give an important boost to the nascent field. The fact that such a vanishingly small number of LSD molecules could exert such a profound effect on the mind was an important clue that a system of neurotransmitters with dedicated receptors might play a role in organizing our mental experience. This insight eventually led to the discovery of serotonin and the class of antidepressants known as SSRIs.

The idea that an LSD experience could mimic the DTs “seemed so bizarre that we laughed uproariously,” Hoffer recalled years later. “But when our laughter subsided, the question seemed less comical and we formed our hypothesis …: would a controlled LSD-produced delirium help alcoholics stay sober?” Here was an arresting application of the psychotomimetic paradigm: use a single high-dose LSD session to induce an episode of madness in an alcoholic that would simulate delirium tremens, shocking the patient into sobriety. Over the next decade, Osmond and Hoffer tested this hypothesis on more than seven hundred alcoholics, and in roughly half the cases, they reported, the treatment worked: the volunteers got sober and remained so for at least several months. Not only was the new approach more effective than other therapies, but it suggested a whole new way to think about psychopharmacology. “From the first,” Hoffer wrote, “we considered not the chemical, but the experience as a key factor in therapy.” This novel idea would become a central tenet of psychedelic therapy.

And yet, successful as the new therapy seemed to be, there was a nagging little problem with the theoretical model on which it was based. When the therapists began to analyze the reports of volunteers, their subjective experiences while on LSD bore little if any resemblance to the horrors of the DTs, or to madness of any kind. To the contrary, their experiences were, for the most part, incredibly—and bafflingly—positive. When Osmond and Hoffer began to catalog their volunteers’ session reports, “psychotic changes”—hallucinations, paranoia, anxiety—sometimes occurred, but there were also descriptions of, say, “a transcendental feeling of being united with the world,” one of the most common feelings reported. Rather than madness, most volunteers described sensations such as a new ability “to see oneself objectively”; “enhancement in the sensory fields”; profound new understandings “in the field of philosophy or religion”; and “increased sensitivity to the feelings of others.”fn3 In spite of the powerful expectancy effect, symptoms that looked nothing like those of insanity were busting through the researchers’ preconceptions.

one of the best ways to avoid a bad session was the presence of an engaged and empathetic therapist, ideally someone who had had his or her own LSD experience.

But however it worked, it worked, or certainly seemed to: by the end of the decade, LSD was widely regarded in North America as a miracle cure for alcohol addiction.

Critics of treating alcoholics with LSD concluded that the treatment didn’t work as well under rigorously controlled conditions, which was true enough, while supporters of the practice concluded that attention to set and setting was essential to the success of LSD therapy, which was also true.

In the mid-1950s, Bill Wilson, the cofounder of Alcoholics Anonymous, learned about Osmond and Hoffer’s work with alcoholics. The idea that a drug could occasion a life-changing spiritual experience was not exactly news to Bill W., as he was known in the fellowship. He credited his own sobriety to a mystical experience he had on belladonna, a plant-derived alkaloid with hallucinogenic properties that was administered to him at Towns Hospital in Manhattan in 1934. Few members of AA realize that the whole idea of a spiritual awakening leading one to surrender to a “higher power”—a cornerstone of Alcoholics Anonymous—can be traced to a psychedelic drug trip.

Bill W. thought there might be a place for LSD therapy in AA, but his colleagues on the board of the fellowship strongly disagreed, believing that to condone the use of any mind-altering substance risked muddying the organization’s brand and message.

Yet when Cohen finally tried LSD himself in October 1955, he “was taken by surprise.” Expecting to find himself trapped inside the mind of a madman, Cohen instead experienced a profound, even transcendent sense of tranquillity, as if “the problems and strivings, the worries and frustrations of everyday life [had] vanished; in their place was a majestic, sunlit, heavenly inner quietude … I seemed to have finally arrived at the contemplation of eternal truth.” Whatever this was, he felt certain it wasn’t a temporary psychosis. Betty Eisner wrote that Cohen came to think of it instead as something he called “unsanity”: “a state beyond the control of the ego.”