Stanford psychology and law professor David Rosenhan could transfix an audience in a crowded lecture hall with just a few words.

“What is abnormality?” he would ask undergraduate students, his deep and resonant golden voice building and booming. “What are we here for? Some things will be black … Others will be white. But be prepared for shades of gray.”

Rosenhan would know. His own life, as I would later find out, was filled with shades of gray.

He wasn’t particularly attractive — the word often used to describe him was “balding” — but there was something magnetic, even seductive, about him, especially in front of a crowd.

His students called it a gift, describing his ability to “rivet a group of two to three hundred students with dynamic lectures that are full of feeling and poetry.” One student recalled how Rosenhan opened one of his lectures while sitting on a student’s lap — as a way to test the class’ reaction to abnormal behavior.

His research work was also groundbreaking. In 1973, Rosenhan published the paper “On Being Sane in Insane Places” in the prestigious journal Science, and it was a sensation. The study, in which eight healthy volunteers went undercover as “pseudopatients” in 12 psychiatric hospitals across the country, discovered harrowing conditions that led to national outrage. His findings helped expedite the widespread closure of psychiatric institutions across the country, changing mental health care in the US forever.

Fifty years later, I tried to find out how Rosenhan had convinced his subjects to go undercover as psychiatric patients and discovered a whole lot more. Yes, Rosenhan had charm. He had charisma. He had chutzpah to spare. And, as I eventually uncovered, he was also not what he appeared to be.

I stumbled across Rosenhan and his study six years ago while on a book tour for my memoir “Brain on Fire,” which chronicled my experiences with a dangerous misdiagnosis, when doctors believed that my autoimmune disorder was a serious mental illness. After my talk, a psychologist and researcher suggested that I could be considered a “modern-day pseudopatient” from Rosenhan’s famous study.

Reading the study for the first time that night in my hotel room, I was struck by its opening words: “If sanity and insanity exist, how shall we know them?” Psychiatry had been struggling throughout its history to answer this question, and Rosenhan’s paper, with its rigorous data collection, exposed the deep limitations in our attempt to answer it.

Rosenhan’s eight healthy pseudopatients allegedly each followed the same script to gain admittance to psychiatric hospitals around the country. They each told doctors that they heard voices that said, “Thud, empty, hollow.” Based on this one symptom alone, the study claimed, all of the pseudopatients were diagnosed with a mental illness — mostly schizophrenia.

And once they were labeled with a mental illness, it became impossible to prove otherwise. All eight were kept hospitalized for an average of 19 days — with the longest staying an unimaginable 52. They each left “against medical advice,” meaning the doctors believed that they were too sick to leave. A total of 2,100 pills — serious psychiatric drugs — reportedly were prescribed to these otherwise healthy individuals.

At the time, the collective American imagination was deeply suspicious of psychiatry and its institutions. It was the era of Ken Kesey’s “One Flew Over the Cuckoo’s Nest” and movies like “Shock Corridor” and “The Snake Pit.” Rosenhan — who was both an insider who studied abnormal psychology, and an outsider who was a psychologist rather than a psychiatrist — was the perfect person to pull back the curtain on psychiatry’s secrets.

His paper had an outsize impact and sparked further movements in the mental health world — helping to debunk Freudian psychoanalysis, medicalizing psychiatry and pushing for mental health patients’ rights, to name just a few. His conclusions were “like a sword plunged into the heart of psychiatry,” an article in the Journal of Nervous and Mental Diseases observed three decades later.

When I read his paper, I recognized my own experience with misdiagnosis in those nine pages. I saw the power of labels, the feeling of depersonalization as a psychiatric patient, the hopelessness.

I wanted to learn more about the study, about the participants who, at the urging of the charismatic Rosenhan, would put their lives on the line to volunteer for such a treacherous assignment.

So I was surprised to find that so little had been written about his study beyond the piece in Science. None of the pseudopatients had gone public and Rosenhan, sadly, had died in 2012. Instead, I started talking to the people who’d been closest to him during his life and career to try to understand the professor who had accomplished such a coup.

“He had a twinkle,” Florence Keller, a close friend, recalled.

“If [a] party were dead, he would walk in and all of a sudden the party would come alive,” his son Jack Rosenhan recounted.

“I think he always made people feel special,” his research assistant Nancy Horn said.

Disappointed that I could never meet him myself, I was thrilled when Keller introduced me to a treasure trove of documents he had left behind — including many never before seen: his unpublished book, diary entries and reams of correspondence.

The first pseudopatient — “David Lurie” in his notes — was very clearly Rosenhan himself.

“It all started out as a dare,” Rosenhan told a local newspaper. “I was teaching psychology at Swarthmore College, and my students were saying that the course was too conceptual and abstract. So I said, ‘OK, if you really want to know what mental patients are like, become mental patients.’ ”

Soon after that, Rosenhan went undercover for nine days at Haverford State Hospital in Haverford, Pa., in February 1969. His diary and book describe a host of indignities: soiled bathrooms without doors, inedible food, sheer boredom and ennui, rank disregard by the staff and doctors. Rosenhan even witnessed an attendant sexually assault one of the more disturbed patients. The only time Rosenhan was truly “seen” as a human by the staff was when an attendant mistook him for a doctor.

The experience was harrowing. After nine days, he pushed for a release and made sure that his undergraduate students — who were planning to follow him as undercover patients into the hospital — would not be allowed to go. Colleagues described a shaken, changed man after his experience.

I dug deeper. If his own students were forbidden from pursuing the experiment after this dismaying event, who were the others who had willingly followed in Rosenhan’s footsteps? Why did they put their mental health — even their lives — on the line for this experiment?

The further I explored, the greater my concerns. With the exception of one paper defending “On Being Sane in Insane Places,” Rosenhan never again published any studies on psychiatric hospitalization, even though this subject made him an international success.

He had also landed a lucrative book deal and had even written eight chapters, well over a hundred pages of it. But then Rosenhan suddenly refused to turn over the manuscript. Seven years later, his publisher sued him to return his advance. Why would he have given up on the subject that made him famous?

I also started to uncover serious inconsistencies between the documents I had found and the paper Rosenhan published in Science. For example, Rosenhan’s medical record during his undercover stay at Haverford found that he had not, as he had written in his published paper, only exhibited one symptom of “thud, empty, hollow.” Instead, he had told doctors that he put a “copper pot” up to his ears to drown out the noises and that he had been suicidal. This was a far more severe — and legitimately concerning — description of his illness than he had portrayed in his paper.

Rosenhan, I began to realize, may have been the ultimate unreliable narrator. It’s possible some pseudopatients he mentioned in his study never existed at all. - Susannah Cahalan, author of “The GreatPretender,” on famed psychology professor David Rosenhan

Meanwhile, I looked for the seven other pseudopatients and spent the next months of my life chasing ghosts. I hunted down rumors, pursuing one dead end after the next. I even hired a private detective, who got no further than I had.

After years of searching, I found only one pseudopatient who participated in the study and whose experience matched that of Rosenhan: Bill Underwood, who’d been a Stanford graduate student at the time.

The only other participant I discovered, Harry Lando, had a vastly different take. Lando had summed up his 19-day hospitalization at the US Public Health Service Hospital in San Francisco in one word: “positive.”

Even though he too was misdiagnosed with schizophrenia, Lando felt it was a healing environment that helped people get better.

“The hospital seemed to have a calming effect. Someone might come in agitated and then fairly quickly they would tend to calm down. It was a benign environment,” Lando, now a psychology professor at the University of Minnesota, recalled in an interview.

But instead of incorporating Lando into the study, Rosenhan dropped him from it.

Lando felt it was pretty obvious what had happened, and I agree: His data — the overall positive experience of his hospitalization — didn’t match Rosenhan’s thesis that institutions are uncaring, ineffective and even harmful places, and so they were discarded.

“Rosenhan was interested in diagnosis, and that’s fine, but you’ve got to respect and accept the data, even if the data are not supportive of your preconceptions,” Lando told me.

Rosenhan, I began to realize, may have been the ultimate unreliable narrator. And I believe it’s possible some of the other pseudopatients he mentioned in his study never existed at all.

As a result, I am now seriously questioning a study I had once admired and had originally planned to celebrate. In my new book “The Great Pretender” (Grand Central Publishing), out this week, I paint the picture of a brilliant but flawed psychologist who was likely also a fabulist.

It wasn’t what I intended, and I feel conflicted about my findings. I have so enjoyed dropping into Rosenhan’s world and getting to know his mind and his loved ones — but I have no doubt that his creation, one that touches all of our lives, is flimsy at best. And it’s time for the world to see the study for what it really is.

It’s not the first time a paper published by an esteemed journal has been called into serious question, or even exposed as an outright lie. There was Dutch social psychologist Diederik Stapel, once renowned for finding a correlation between filthier train platforms and racist views at an Utrecht station, who is now infamous for inventing data.

Philip Zimbardo, the architect of the famous prison study, which took place in Stanford’s basement in 1971, has also come under fire. Zimbardo and his researchers recruited students and assigned them roles as “inmates” or “guards.” Guards abused inmates; inmates reacted as real prisoners. A 2018 Medium piece tracked down the original participants in that study and exposed serious issues — including the fact that Zimbardo had coached the guards into behaving aggressively.

Psychologist Peter Gray told me that he sees the work of researchers such as Zimbardo and Rosenhan as prime examples of studies that “fit our biases … There is a kind of desire to expose the problems of society but in the process cut corners or even make up data.”

This may explain Rosenhan. He saw real problems in society: The country was warehousing very sick people in horror houses pretending to be hospitals, our diagnostic systems were flawed and psychiatrists in many ways had too much power — and very little substance. He saw how psychiatric labels degraded people and how doctors see patients through the prism of their mental illness. All of this was true. In many ways, it is still true.

But the problem is that scientific research needs to be sound. We cannot build progress on a rotten foundation.

In disregarding Lando’s data and inventing other facts, Rosenhan missed an opportunity to create something three-dimensional, something a bit messier but more honest. Instead, he helped perpetuate a dangerous half-truth.

And today, what we have is a mental health crisis of epic proportions. Over 100,000 people with serious mental illnesses live on the streets, while we are chronically short of safe housing and hospital beds for the sickest among us.

Had Rosenhan been more measured in his treatment of the hospitals, had he included Lando’s data, there’s a chance a different dialogue, less extreme in its certainty, would have emerged from his study, and maybe, just maybe, we’d be in a better place.

Susannah Cahalan is the author of “The Great Pretender” about famed psychology professor David Rosenhan, whom she discovered while on a book tour for her memoir, “Brain on Fire.” The book chronicled her experiences with doctors who believed her autoimmune disorder was a serious mental illness.