What does it take to be thought of as mentally ill? According to one of the most famous studies in psychiatry, very little. In 1973, the journal Science published “On Being Sane in Insane Places” by the Stanford psychologist David Rosenhan. The paper recounted how he and seven other researchers had gone separately to different psychiatric hospitals and presented a single symptom: hearing voices that said “thud, empty, hollow”. Based on this, they were all committed, most being diagnosed with schizophrenia, and spent an average of 19 days institutionalised against their wills. “We now know,” the paper alarmingly concluded, “that we cannot distinguish insanity from sanity.”

The paper made Rosenhan a celebrity and fed into the wider anti-psychiatry movement in the culture of the time: One Flew Over the Cuckoo’s Nest, RD Laing’s The Divided Self, and so forth. The message that the psychiatric emperor had no clothes spurred other researchers in a grand attempt to put the discipline back on a strictly scientific footing with the compilation of the first DSM (Diagnostic and Statistical Manual) for mental illness. Rosenhan, meanwhile, received a handsome book advance to expand on his research – but, oddly, he never finished that potentially very lucrative project.

Which was the first clue to the big problem in this whole story: that, according to Susannah Cahalan’s brilliant detective work detailed in this book, very little in the paper had happened in the way Rosenhan said it had. Some of his colleagues had suspected all along that the charismatic lecturer was also a “bullshitter”. One of the surviving “pseudopatients” tracked down by Cahalan was eliminated from the study because during his hospital stay he was treated very well and enjoyed the experience (partly because, he now guesses, he really was depressed at the time). Another had false details inserted in his account. And the rest, she concludes, were probably wholly fabricated.

This story is fascinating enough in itself, but as Cahalan points out, it also has relevance to the current “replication crisis” in psychology, where many celebrated findings have dissolved once other researchers attempt to repeat the experiments. But does it have anything to teach us specifically about psychiatry as it is practised today? Cahalan’s own view of the discipline has been coloured by her experience, detailed in her previous book Brain on Fire, of being treated as schizophrenic before it was discovered that she instead had an autoimmune inflammation of the brain, and from this unpleasant experience she has derived critical opinions of what she calls “the whole system” that treats mental illness.

She argues that the paper revealed a truth (about the unreliability of psychiatric diagnosis back then) even though it was fraudulent, and in some sense this is right, but it’s notable that she spices up her narrative with horrible stories from psychiatry’s dubious past (including the devastating lobotomy imposed on JFK’s sister Rosemary), without ever going into comparable detail about its numberless anonymous successes. Indeed, the most damning revelation of Rosenhan’s fraud, as she shows, is actually an example of psychiatry working exactly as we wish it should. Rosenhan got himself committed by going much further than sticking to the one symptom he describes having offered in his paper – voices saying “thud, empty, hollow”; he also told the admitting psychiatrist, Frank Bartlett, that he was sensitive to radio waves and could hear what people were thinking, and – most seriously – that he was suicidal. Cahalan discovered this by digging up Bartlett’s own notes of their first interview. As it turns out, committing Rosenhan was the only thing a responsible doctor could have done – and could still do today. As Cahalan herself comments: “Dr Bartlett wasn’t a bad doctor who made a bad decision … He was a good doctor who made the best call given the information he received.”

By the end of the book, she has adopted a more optimistic view, looking forward to new brain-scanning technologies and genetic research that might enhance our understanding of what can go wrong within the brain, the most complex object in the known universe. She does also finally concede that modern psychiatry helps untold numbers of ordinary people: psychiatric drugs “help many people lead full and meaningful lives”, she writes. “It would be folly to discount their worth.” But by the time of this grudging admission, pages from the end, this book might have been happily seized on by cultists and fearmongers who want to dismiss the discipline as a conspiracy cooked up by Big Pharma and the authoritarian state. The truth is that psychiatry, along with medicine in general, remains a highly imperfect science – but the book’s polemical implication that it has not moved on much since 1973 has the potential to be truly harmful to anyone thinking about seeking help now.

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