There’s an interesting post from Duncan Double, MD titled Why does the APA need new editions of DSM?
Dr. Double is a psychiatrist and a member of the Critical Psychiatry Network. In his current article, Dr. Double expresses the hope that there won’t be a DSM-6, essentially on the grounds that none of the revisions up to this time has resulted in any increase in validity. So each revision, in effect, replaces an invalid old manual with an invalid new one.
Dr. Double’s final two sentences express the matter very well:
“However, despite all the DSM revisions, there’s no getting away from the poor validity and reliability of psychiatric diagnosis. That’s its nature and psychiatry’s wishful failed ambition needs to be recognised for what it is.”
In other words, psychiatric diagnosis is intrinsically (in its nature) invalid.