Your argument is highly misleading, First, Rosenhan was commenting on the state of psychiatry at the time rather than making a universal statement. Second, the Diagnostic and Statistical Manual of Mental Disorders (DSM)--today regarded as the Bible of psychiatry--was not written yet, meaning that psychiatry was at a state where repeatable metrics had not been defined and ratified for everyday use by medical professionals. In fact, Rosenhan's experiment was one of the catalysts that led to the creation of the DSM. Your comment supports a sentiment that is vastly outdated and no longer supported by the current state of psychiatric research.

"Your comment supports a sentiment that is vastly outdated and no longer supported by the current state of psychiatric research."

[Citation needed]

I am no psychiatrist, but from what I've read, the current consensus indicates that psychiatric orders can be detected using reasonable criteria. The widespread use of the DSM demonstrates this idea. The DSM is occasionally updated, and each revision reflects the changing ideas about psychiatry.

Source: http://www.nytimes.com/2012/05/12/us/dsm-revisions-may-sharp...

40 years ago psychiatry was very different than it is today.

"40 years ago psychiatry was very different than it is today."

[Citation needed]