Final answer:
David Rosenhan's experiment involved eight 'fake patients' who were not recognized as impostors and were diagnosed with psychiatric conditions. Their experiences highlighted issues in psychiatric diagnosis and treatment, and questioned the reliability of mental health institutions in differentiating sanity from insanity.
Step-by-step explanation:
The case you're referring to involves David Rosenhan's famous experiment on the legitimacy of psychiatric diagnoses. In this study, none of the eight "fake patients" were immediately recognized as impostors. Instead, they were admitted to various psychiatric hospitals with psychiatric diagnoses.
Despite only simulating symptoms of auditory hallucinations initially, all were admitted and prescribed psychiatric medications. Their imposture went largely undetected by hospital staff, but interestingly, some actual patients suspected their ruse. The study criticized early psychiatric practices and highlighted the dangers of dehumanization and labeling in mental health institutions. It suggested that psychiatric diagnoses could be unreliable and questioned the validity of psychiatric institutions' ability to distinguish between sanity and insanity.