We believe that a systematic approach, using diagnostic classification by criteria, enhances psychiatric research that, in turn, leads to an increase in accuracy of that classification. Also, using diagnostic criteria to arrive at a psychiatric diagnosis serves as a safeguard against bias in diagnostic impression when a major psychiatric symptom dominates the clinical picture.
Some of the conclusions arrived at by our studies were the following: (1) Most patients whose conditions were undiagnosed by clinical impression were diagnosed when systematically studied, using criteria for diagnostic classification; and (2) With the exception of antisocial personality, we could not classify personality disorders by criteria; rather, most of these patients met the criteria for one or more psychiatric disorders.
Amos Welner, Jay L. Liss, Eli Robins. A Systematic Approach for Making a Psychiatric Diagnosis. Arch Gen Psychiatry. 1974;31(2):193–196. doi:10.1001/archpsyc.1974.01760140045007