In a strange sense, an admission of the arbitrary frailties of psychiatry. This was an attempt to 'standardize' descriptive diagnosis of syndromes and conditions, because shrinks basically diagnosed in haphazard ad hoc ways. Shrinks from different countries used different labels i.e. some called certain kind of manic depression schizophrenia, some called certain schizophrenia manic depression etc. They didn't agree so they had to create a system.
#humor