Mutually exclusive diagnosis harms patients by hiding causal links between overlapping disorders.

Evidence

In short, the reality of diseases as well as the methodology of classification produces all kinds of boundary problems. It is more realistic and probably better for the patient to be realistic about multiple disorders. It is quite possible that one disorder is a major cause of another related one. It could well be that the one that seems less important is actually causing the one that has a higher percentage of symptoms. Dichotomizing and using mutually exclusive categories serve no one very well, except perhaps for the practicalities of getting insurance, and perhaps as a timesaver for clinicians. — Gary Goertz, Social Science Concepts and Measurement, 1259

Categorization

• ADDENDUM: Extends the taxonomy-critique theme into applied medicine, paralleling the book’s broader argument that category systems distort what they describe.