“Mentally healthy in place of the insane” is what David Rosenhan—a professor of psychology and law at Stanford University—called his exposé article. Before him, journalists and psychiatrists had repeatedly penetrated psychiatric institutions undercover, but for the first time such an operation was carried out on such a large scale and accompanied by the collection of detailed empirical data—and its result was the publication in the leading scientific journal “Science.”
Rosenhan’s study became “a sword that pierced the very heart of psychiatry”: it undermined its authority, sparked fierce debates among psychiatrists, and influenced the development of a new system for diagnosing mental illnesses. Its significance is hard to overestimate, but decades later, when there were almost no living witnesses to the famous experiment, Susanna Cahalan took it on to investigate Rosenhan’s story.
She was led down this path by another “great impostor”—autoimmune encephalitis, a disease whose symptoms mimicked schizophrenia and bipolar disorder, but were caused by physical causes—obvious dysfunctions of the body. Her turn to the Rosenhan experiment is an attempt to answer the main question that matters to her: if sanity and insanity exist, how can we tell them apart?