David Rosenhan suspected that American psychiatrists could not reliably distinguish between those who were mentally ill and those who were not.
He questioned whether the system used for classifying the mentally ill was at all valid or accurate.
He therefore decided to make two experiments to test his hypothesis.
Method/Design - Experiment 1
Two experiments. Both studies are 'field experiments' as they took place in real hospitals around the USA.
Experiment no. 1 involved eight 'pseudo patients' trying to gain admittance into twelve various mental hospitals. The mental hospitals knew nothing of the experiment. When interviewed, the pseudo-patients would claim to hear voices saying things such as "thud", "empty", "hollow".
Other than these symptoms, they were told to act as 'normal' as possible. Every single one was admitted into hopsital on the grounds of hearing voices alone. Even on the ward, their various activities such as pacing the corridors and writing notes were seen as signs of obsessive compulsive disorder (as opposed to the reality of plain boredom!)
Upon leaving the ward after a short while, they were still labelled with "Schizophrenia on remission" suggesting the impact a diagnosis of abnormality really has.
The other involved NO pseudo patients, although Rosenhan told the mental hospitals that he would be replicating the first study and sending one or more pseudo-patient within the next three months.
Using a ten-point scale, the doctors were asked to rate each patient's probability of actually being a pseudo-patient. Of nearly 200 patients, just under a quarter were confidently judged to be schizophrenic and an eighth suspected by at least one doctor.
From these findings, Rosenhan concluded that psychiatrists were not able to detect the sane from the insane and that therefore, psychiatric diagnosis was unreliable and invalid for today.
- Deception issues of the various mental hospitals involved and of the patients on the ward in the first experiment (who may have felt intruded upon or mimicked in some way)
- In terms of the second experiment, the doctors and nurses were made to fill out forms which were not even necessary as none of the following patients were indeed pseudo-patients. Time-consuming
- Lower ecological validity, considering there usually needs to be agreed assessment diagnostic criteria for a potential mental patient by two or more doctors and Rosenhan's experiment did not include this.
- Since this experiment, many fautls have been made right and perhaps the psychiatric classification system has improved because of such ground breaking findings.