The impact of classification on psychopharmacology and biological psychiatry.

Nosological classification in psychiatry, as it is currently applied, does not facilitate biological and psychopharmacological research. • Syndromal acuity has disappeared. Consequently, it is impossible to determine: (i) vi/hether a particular drug affects a particular symptom configuration; (ii) what exactly the behavioral correlate of a particular biological disturbance is. The problem of unfocused diagnoses is greatly magnified by the phenomenon called comorbidity. • The boundary between distress and disorder is illdefined. • Symptom configuration and certain nonsymptomatological variables such as duration and severity are prematurely linked, so as to conceptualize categorical entities. The validity of those constructs has not been sufficiently demonstrated. This undermines the validity of biological studies and leads to “nosologomania,” ie, an ever-growing series of undervalidated psychiatric “disorders.” • Symptoms are grouped horizontally as if they all had the same diagnostic “valence.” This, however, is highly unlikely. • The nosological disease model is unconditionally and uncritically accepted. Alternative models are ignored, particularly the reaction-form model, though it has substantial heuristic value, and deserves to be thoroughly scrutinized. (Research) strategies to remedy this situation are pointed out.