Elizabeth closed her eyes and was immediately inside the nauseating memory. Half an hour earlier, she'd swallowed a capsule filled with grayish crystals of MDMA. Before that, her therapist, Holly, had painted circles on the ground around her with burnt sweet-grass. The smell lingered. Elizabeth (that's a pseudonym) felt her legs start to shake. She was stretched back on an unfamiliar futon with her feet together and her knees open in a butterfly position. She saw Holly to her left, still and steady, watching. As Elizabeth closed her eyes again, her mind shoved her straight into reliving her rape.

"Trauma is the way into the self, and the way out. To be free, to come to terms with our lives, we have to have a direct experience of ourselves as we really are, warts and all," writes Mark Epstein, a psychotherapist who combines the teachings of Sigmund Freud and the Buddha, in his book, The Trauma of Everyday Life. Confronting and even embracing trauma isn't a new concept, and it's never been an easy one. But Holly (also a pseudonym) is one of a number of practitioners who believe that hallucinogenic drugs offer a tool with which to face particularly difficult trauma or anxiety.

Holly is a licensed marriage and family therapist with a robust private practice. She uses a blend of techniques and traditions in her therapy sessions: Jungian talk therapy, Reiki, Somatic therapy, Hakomi, and—secretly and illegally—psychedelic-assisted therapy.

Hallucinogenic therapy, a longstanding underground therapeutic movement, is now reaching research institutions like Johns Hopkins. Studies explore the ability of psychedelics to amplify access to thoughts and feelings. Research results are promising enough that the Food and Drug Administration recently designated MDMA-assisted psychotherapy a "breakthrough therapy" for post-traumatic stress disorder, which essentially fast-tracks the last phase of clinical trials before medicalization.

Holly operates outside the framework of legal research work. She counts herself as a member of "The Underground," a quiet community of illicit, therapeutic psychedelic use. She risks her license when she takes clients on psychedelic trips, but does so because she so strongly believes that this type of therapy can be a transformational experience. She's borne witness to enough of those to convince her it works. And if patients want out of stubborn pain, she would feel wrong withholding the therapy that works.

Holly abides by firm guidelines for her psychedelic-assisted therapy. She combines knowledge from indigenous tradition, current legal research protocol, and time-tested field findings to direct her practice. Those principles are not universal—some therapists are looser with their interpretations.

In her normal course of three preparation sessions, she asks about her patients' medical history: Any heart conditions? Taking any medications that affect blood pressure? Yes answers would disqualify a patient for psychedelic use in her practice. MDMA increases heart rate. She probes into their psychological state: Any signs of paranoia or schizophrenia? Because psychedelics can destabilize the perception of reality, those without what Holly calls "a strong sense of self" may have a bad reaction.

Holly uses psychedelics with patients only once or twice in the course of her work with them. When she does, it's usually MDMA, which she finds works well for dealing with trauma. In some cases, she'll move on to psilocybin, which she uses for deeper exploration and for depression and anxiety.

Holly uses psychedelics with patients only once or twice in the course of her work with them.

It is the work after the trip, according to Holly and many other Underground therapists, that is often the most important part. She says the benefit doesn't come from the peaks of trips; in fact, jumping from one peak experience to another is harmful. Post-trip sessions, called integration, involve translating the feelings and insights from the psychedelic experience into everyday life.

Integration can mean continued therapy sessions. It can involve writing a letter, having a conversation or confrontation, or starting a mediation practice. In integration, a patient digests the trauma that once shocked their system with the stability that they learned on their trip.

For Holly, that trauma came as a child, when she was molested by someone close but unrelated to her. Her family didn't handle it well—or at all. "Any kid is going to take it upon themselves, that it's their fault, they did something wrong," Holly says. "That was just my ongoing narrative."

Through guided MDMA-assisted therapy, she revisited that early trauma and the narrative that emanated from it. Her year of work came from integrating what she learned from one particular revelation. "In a single session, we were able to get to the point in my history where I had some memory that started the belief," she says. They plunged into her recollections and explored. It was as if the memory of her molestation was a heavy object on a pedestal before her. Holly inspected it like an artifact of her ancestors, connected to her, but removed of the pain of carrying it around.

"Oh yes, that happened," she says, closing her eyes. "That's so sad for that little girl."

Her inner conversation continues: "Yes, it was really complex for the family to deal with it. They didn't know what they were doing."

The anger, what she calls a "ball of trauma energy," is not embedded in the memory anymore. And that means that how she interacts with her family, or with people she previously mistrusted, has changed. Objectivity has become a real tool with which to see the most painful of circumstances.

MDMA therapy first began in the 1970s, building upon previous experiments from the 1950s and '60s using another hallucinogen: LSD. But by the 1980s, amid Nancy Reagan's "Just Say No" campaign, any kind of drug used in public was a target for criminalization. In California, The Underground worked quietly to spread the use of MDMA. They called the drug "Adam" as code—Adam, the primal innocent.

Some were deterred by the risks associated when, in 1984, the Drug Enforcement Administration placed MDMA on the schedule of illicit substances. Others who had been using the substance in their sessions continued to do so quietly. Practitioners who led the early movement crafted what amounted to lineages of practice, and small clusters of followers took on their various approaches. Others shifted their focus to funding federally sanctioned research. In 1992, the FDA approved a basic human clinical trial of the psychological and physiological effects of MDMA, but the first therapeutic research didn't formally begin in the United States until 2004.

One 2014 study measured the changes in participants' emotions on MDMA. Nineteen participants submitted six of their favorite memories and six of their worst memories. Once they ingested either MDMA or a placebo, they were cued to remember these different memories. Participants on MDMA rated good memories as more positive and intense than the patients given the placebo; MDMA patients also found their worst memories to be less negative than placebo patients.

More intriguing is what showed up on fMRI scans during the study. Images that measured blood flow in the brain while a participant did a task showed major activation in response to favorite memories and less activity in response to worst memories. Not only did MDMA change the way blood flow waxed and waned, but it also changed where blood flow took place. In response to happy memories, more blood swirled around the hippocampus, the center of emotion, memory, and unconscious body function (like breathing and digestion). Essentially, MDMA was able to make good thoughts stronger and bad thoughts weaker.

"You can get to content that usually would have heightened defenses," Holly says of psychedelic therapy. "It's assisted therapy. It's really all it is." A 2016 study in the Journal of Psychotherapy Integration found that, for successful psychotherapy outcomes, "the most important common factor was the therapeutic alliance," meaning the relationship between the patient and therapist.

"That kind of opening to access of thoughts and feelings can be disturbing if too much comes too quickly and one isn't in a setting to help guide and contain that."

"I'm back in the room." Elizabeth, eyes closed, told Holly, who replied with a gentle nudge, "What do you see?" It was dark, but Elizabeth could feel the comforter underneath her; she could smell the room, the college stench, the sweaty fabric and skin. It was a mute memory; the room was silent but for the echo of her own sharp breathing. She could feel the motion of her hips without the pain of the penetration. She could also open her eyes and be back in the basement studio, warm with Holly's presence.

"That kind of opening to access of thoughts and feelings can be disturbing if too much comes too quickly and one isn't in a setting to help guide and contain that," says David Presti, a neurobiologist and psychologist at the University of California–Berkeley who has closely followed the research in psychedelic science for 30 years. "That's presumably why psychedelics used in a casual way can lead to so-called bad trips or cause people to be overwhelmed with anxiety. In cases where people who are psychologically stable are given these substances in a therapeutic setting, the results are uniformly positive."

Yet others have been critical of the excitement over psychedelic therapy research. Richard Friedman, professor of clinical psychiatry and the director of the psychopharmacology clinic at Cornell Medical School, says that his concern with using MDMA to facilitate therapy rests on the very quality that underground therapists utilize it for: that patients feel receptive and open to experiences they ordinarily might not be.

He describes the anticipation that comes when you see the bud of a rose. One day it might bloom on its own. But perhaps, out of curiousness and eagerness, you pry its petals open. "Great," he says. "Now you've got a rose. Sort of a half-dead rose, but you've got it." Friedman analogizes the rose to the brain: "You have bypassed the person's inclinations and resistance to get material."

Holly sees those inclinations and resistance differently. She doesn't think you maim the rose by freeing it—if that liberation comes under the right conditions and is followed by thoughtful integration. She thinks that the trappings of the mind often prevent people from accessing who they really are. And after seeing many patients experience relief, Holly says she's compelled to continue.

Elizabeth will come back to Holly's office, far from the rented basement. Holly will sit steadily in a dark leather armchair. They'll talk beneath the protective hum of a sound machine near Holly's door. They'll unpack memories and discuss how to best integrate Elizabeth's newfound objective compassion. They think of it as a tool, a pair of eyeglasses to reach for when things get blurry.

After the appointment, Holly will take notes that make no mention of Elizabeth's MDMA-assisted session. She keeps her practices separate. Psychedelic therapy is only for those who ask, and who come to her by word of mouth from highly trusted colleagues. She realizes there are rigid flowers she can't help to bloom, and tight knots she can't help to untangle. She wonders what it would be like for more people to have less pain, thorns and all.