Models of scientific progress and the role of theory in taxonomy development: a case study of the DSM.

The proliferation of categories in recent editions of the Diagnostic and Statistical Manual of Mental Disorders (e.g., 4th ed.; DSM; American Psychiatric Association, 1994) is discussed as an indication that the underlying classification scheme is inadequate and unlikely to produce the scientific progress originally envisioned. In any nosological system, it eventually becomes necessary to reduce the number of categories by an organizing theory that describes the fundamental principles underlying the taxonomy. The DSM has put itself in an awkward position by claiming to be atheoretical. Although taking such a tack had historical advantages to promote the acceptability of the 3rd edition of the DSM, it now limits the progression of science. It is argued that the DSM should not be used as the basis for guiding scientific research programs because it emphasizes primarily behavioral topography rather than providing an explicit theory that would allow for an evaluation of scientific progress. Theoretically driven taxonomies should be allowed to compete on the basis of how successful they are at achieving their specified goals that might include illuminating etiology, course, and response to treatment. Such systems are not likely to attend primarily to behavioral topography alone and would probably organize behavior differently than the current categorical syndromes seen in the 4th edition of the DSM.