Or at least that's the version told in Adam Curtis' documentary The Trap (part 1)[1] which engages in Curtis's usual enthusiasm for fashioning a sweeping historical narrative out of somewhat sparse materials - in this case presenting the "Thud" experiment and its followup as a pivot point in the tale of how R. D. Laing's anti-psychiatry ironically led to the advent of the DSM IV era.
However that may be, if Curtis' account of the followup is correct it seems harder to argue the diagnostic prowess of the psychiatrists was not open to question, regardless of the status of the original experiment.
1: In the section beginning here: https://youtu.be/y97Ywl7RtUw?t=2204
The reason is simple. This article is pure propaganda along the lines of the book "The great pretender" by Susannah Cahalan.
The experiment might have flaws, but this second part is conclusive and no critics ever address it.
This is just another brick on the long propaganda road to a destination that is very worrisome.
'a hospital' - which hospital?
Makes sense to carefully re-examine the other claims of the paper.