The Hidden Psychometric Model Underlying the DSM: What Happens When It Fails to Fit Psychiatric Data
Diagnostic criteria for a DSM psychiatric diagnosis are typically met by within-criterion symptom counts. Simple sym ptom counts treat each symptom as though it has equal priority (or “weight”) in reflecting underlying disorder severity. In clinical practice, many practitioners understand that “some symptoms matter more than others” (1). Two patients who have the same number of symptoms, but a different pattern of those symptoms, will likely have different underlying disorder severities (2). Thus, a