Forced to remain inside until they'd "proven" themselves sane, all eight emerged with alarming diagnoses and even more troubling stories of their treatment. Rosenhan's study broke open the field of psychiatry, closing down institutions and changing mental health diagnosis forever. But, as Cahalan's new research shows, very little in this saga is exactly as it seems. What really happened behind those closed asylum doors, and what does it mean for our understanding of mental illness today?