Subtypes of schizophrenia: descriptive models.

Descriptive approaches to subtyping schizophrenia use symptoms, signs, and functioning characteristics as diagnostic criteria. Such approaches often appear superficially to be obvious, simple, and atheoretical; in reality, however, there are many ways in which descriptive data can be selected and organized to subtype patients. This report describes these various approaches. Selection of diagnostic criteria can focus primarily either on cross-sectional or longitudinal characteristics of patients. Alternative ways of organizing descriptive data include typological and dimensional approaches and two increasingly common complex models, multiaxial and hierarchical subtyping. Examples and implications of these alternative approaches are described, and methods for choosing among them are suggested.