In the late 2000s, when Ms. Mazel-Carlton was in her mid-20s, a new position arose in mental health: peer-support specialist, someone with what’s known as lived experience who works alongside practitioners. The idea is that peers can better win the trust of people who are struggling. This is a very important movement.

Hearing Voices Network support groups — which are somewhat akin to Alcoholics Anonymous meetings — for people with auditory and visual hallucinations. The groups, with no clinicians in the room, gathered on secondhand chairs and sofas in humble spaces rented by the alliance.

What psychiatry terms psychosis, the Hearing Voices Movement refers to as nonconsensus realities, and a bedrock faith of the movement is that filling a room with talk of phantasms will not infuse them with more vivid life or grant them more unshakable power. Instead, partly by lifting the pressure of secrecy and diminishing the feeling of deviance, the talk will loosen the hold of hallucinations and, crucially, the grip of isolation.

The hard evidence that the medications improve outcomes is murky. And it is countered by other studies suggesting that maintenance on the drugs may actually worsen outcomes and even cause brain atrophy, though these findings have been debated. The area is devoid of conclusive science, a failure that is a prominent part of a wider problem in biomedical psychiatry: its lack of progress in treating serious conditions, or even precisely diagnosing and comprehending them. “Something has gone wrong in contemporary academic and clinical psychiatry,” a 2019 lead opinion piece in The New England Journal of Medicine stated. “We are facing the stark limitations of biologic treatments,” it argued. “There is no comprehensive biologic understanding of either the causes or the treatments of psychiatric disorders.”

Last June, the World Health Organization published a 300-page directive on the human rights of mental-health clients — and despite the mammoth bureaucracy from which it emerged, it is a revolutionary manifesto on the subject of severe psychiatric disorders. It challenges biological psychiatry’s authority, its expertise and insight about the psyche. And it calls for an end to all involuntary or coercive treatment and to the dominance of the pharmaceutical approach that is foremost in mental health care across conditions, including psychosis, bipolar disorder, depression and a host of other diagnoses.

Michelle Funk, a former clinician and researcher who is leading the W.H.O’s work on mental-health policy, law and human rights and is the primary author of the report, spoke to me about the need for a radical change in prevailing clinical presumptions: “Practitioners cannot put their expertise above the expertise and experience of those they’re trying to support.”

Present methods can do damage and undermine outcomes not only through psychotropic side effects, and not only through the power imbalances of locked wards and court-ordered outpatient care and even seemingly benign practitioner-patient relationships, but also through a singular focus on reducing symptoms, a professional mind-set that leaves people feeling that they are seen as checklists of diagnostic criteria, not as human beings.

Mazel-Carlton has been a leader in running Hearing Voices Network groups and training others to do the same around the country, from Augusta, Maine, to Eureka, Calif. H.V.N. originated in the mid-’80s after a Dutch psychiatrist, Marius Romme, worked with a client, Patsy Hage, who was hallucinating and suicidal. Hage insisted that Romme pay attention to the content of her voices instead of dismissing what they said as meaningless. Romme went on to study hundreds of people like Hage, and in a 1989 paper in Schizophrenia Bulletin, he argued that practitioners should “accept the patient’s experience of the voices”; that “biological psychiatry” may not be “very helpful in coping with the voices because it, too, places the phenomenon beyond one’s grasp”; that practitioners should “stimulate the patient to meet other people with similar experiences”; and that patients benefited when they could “attribute some meaning to the voices.” Romme’s paper was mostly ignored, but Hearing Voices support groups cropped up, especially in Britain and across Europe. In the United States, it took much longer; some of the first were started by the alliance around 2008, four years before Mazel-Carlton began working there.

The W.H.O. report features another innovative approach, temporary residences called Soteria Houses. In Israel, Pesach Lichtenberg has founded two of a handful of such houses now operating around the world. At the outset of his career, Lichtenberg was taken with the promise of psychopharmacology. In the mid-1980s, he moved from New York City to Israel for his psychiatric training, and one day, as he made rounds with a senior colleague, a patient spoke “about demons and the messiah and so forth,” he told me. “I was fascinated. I’ve always had the problem of being intrigued. But as we walked away from this person, the senior psychiatrist said: ‘That’s not him. That’s his dopamine talking.’ It struck me as such a wonderful insight.” Lichtenberg laughed at himself almost bitterly. “Today I’m ashamed that I could think this way.”

For 25 years, Lichtenberg ran the psych ward at a Jerusalem hospital. He described his patients as sodden with medication. “Half the dose was to calm the patient, and the rest was to assuage the anxiety of the staff,” he said. Then, in 2016, utterly disillusioned, he opened his first Soteria House in Jerusalem. He was inspired by a book about the Soteria origin story by Loren Mosher, a former head of schizophrenia research at the N.I.M.H., who was appalled by psychiatry’s heavy reliance on antipsychotics. He established a pair of treatment houses in the Bay Area in the 1970s that minimized medication and prioritized two words, “being with,” as the main treatment philosophy.

Clinicians are present but sidelined, hierarchies of knowledge are banished, medication is a secondary option, mostly to be avoided unless residents arrive already on drug regimens, and “being with” is carried out above all by melavim, companions — paid interns whose ameliorative mission is simply to be engaged, empathetic and curious, to leave residents feeling less alien, less alone.

Daniel Bergner is a contributing writer for the magazine. This article is adapted from his book “The Mind and the Moon: My Brother’s Story, the Science of Our Brains, and the Search for Our Psyches,” published this month by Ecco.