On Being Sane in Insane Places

In 1972, a psychologist named David Rosenhan convinced some of his friends to fake their way into psychiatric wards across the US. When Rosenhan's experiment On Being Sane in Insane Places, was published in Science, it outraged the world of psychiatry. It is very interesting reading, especially the sections on depersonalization and also analysis of the time that is actually spent with the patients by doctors and nurses. I suggest you read the whole thing as it is only 13 pages long and written in easy language. The only one of the participants that was not classed schizophrenic was the one that checked into an expensive private hospital.

According to the Wikipedia article on Rosenhan's experiment several other psychiatry bias experiments were later conducted:

Maurice K. Temerlin split 25 psychiatrists into two groups and had them listen to an actor portraying a character of normal mental health. One group was told that the actor "was a very interesting man because he looked neurotic, but actually was quite psychotic" while the other was told nothing. Sixty percent of the former group diagnosed psychoses, most often schizophrenia, while none of the control group did so.

Loring and Powell gave 290 psychiatrists a transcript of a patient interview and told half of them that the patients were black and the other half white; they concluded of the results that "Clinicians appear to ascribe violence, suspiciousness, and dangerousness to black clients even though the case studies are the same as the case studies for the white clients".

Lauren Slater says in her 2004 book Opening Skinner's Box that she repeated Rosenhan's study, by presenting at the emergency rooms of different hospitals with a single auditory hallucination. She writes that she was not admitted to any of them but was instead given prescriptions for antipsychotics and antidepressants, and was also occasionally diagnosed with post-traumatic stress disorder. She makes the connection between her being repeatedly diagnosed as such and the vast majority of pseudopatients in the original experiment being diagnosed as schizophrenic; she suggests that certain mental illnesses become "fashionable" over time.