This paper deals with the fate of eight pseudopatients who had themselves admitted to psychiatric institutions in the early 1970s. The psuedopatients (many of who were involved in the profession of psychiatry or psychology) were thus labelled a specific way upon entry and their behavior (which was "normal" following their admittance) was interpreted with that category in mind. For example, the pseudopatients took a lot of notes during their time at the various facilities and this was commented on by the staff as an indication of their insanity! So the question becomes can we tell the sane from the insane? Apparently the field of psychiatry couldn't in 1973.
Whether a paper this old (it was published in 1973) reflects the current state of psychiatry, etc. I can't say. I do wonder whether a similar experiment produced today would bring about the same result? I think that it is likely that it would. Anyone have any evidence for a conclusion opposite this one?