The Great Pretender: The Undercover Mission That Changed Our Understanding of Madness – an amazing new release and bestselling memoir. As her previous work Brain on Fire investigated the shocking mystery behind the dramatic experiment that revolutionized modern medicine (NPR), Cahalan digs into a whole new area here.

Doctors have struggled for centuries with the diagnosis, treatment, and other corners of insanity, and even the definition. 1970s’ Stanford psychologist David Rosenhan and seven others went undercover into asylums around America to test the labels psychiatry places on insanity labels. Forced to remain inside until they’d “proven” themselves sane, all eight emerged with alarming diagnoses and even more troubling stories of their treatment. This study cracked the field of psychiatry, closing down institutions and changing mental health diagnosis forever. But, as Cahalan’s explosive new research shows here, there is more here than we realize. What really happened in that study?