In reply
The commentaries1,2 and letters addressing our recent ARCHIVES article3 come when both the World Health Organization and American Psychiatric Association are beginning to evaluate evidence requiring revisions of their diagnosis and classification systems.4,5 Because these systems now both contain explicit mental disorder diagnostic criteria, which constitute testable hypotheses for both validity and clinical utility, research evidence is available to guide future revisions. Validity in this context means the ability of criteria to differentiate psychopathology from normal human states based on structural pathology, statistical deviance from physiologic norms, pathognomonic symptom presentation, and syndromal patterns.5(ppxxi-xxii) The Robins and Guze6 approach for testing validity includes assessments of clinical utility for predicting clinical course, treatment response, and familial or genetic risk.