In 1973, psychologist David Rosenhan published "On Being Sane in Insane Places" — one of the most devastating critiques of psychiatric diagnosis ever conducted.

The Study

Rosenhan and seven associates had themselves admitted to 12 different psychiatric hospitals by falsely reporting hearing a voice saying "thud", "empty", and "hollow." All were admitted; 11 were diagnosed with schizophrenia. They then behaved completely normally.

The Results

• None of the pseudopatients were detected by staff as sane — despite all acting normally from day one
• They were held for 7–52 days (average 19 days)
• Real patients frequently identified them as impostors; staff never did
• Normal behaviors like note-taking were recorded in charts as symptoms

The Follow-Up

When hospitals challenged Rosenhan to send more pseudopatients (they would identify them this time), Rosenhan agreed — then sent nobody. Hospitals flagged 41 out of 193 admissions as likely pseudopatients. The false positive rate was enormous.

Legacy

The Rosenhan experiment exposed how diagnostic labels, once applied, shape everything observed thereafter — and accelerated reform of psychiatric diagnosis systems.

Reference:

Wikipedia: Rosenhan Experiment

https://en.wikipedia.org/wiki/Rosenhan_experiment