Two-tier diagnosing in psychiatry.

This article addresses the question: what is the most productive way to systematize abnormal behavior in order to study its biological roots? Though nosology still occupies the premier position in biological psychiatry, it is, in and by itself, a treacherous beacon. Syndromal organization of psychopathology is likewise seriously flawed. A functional organization of psychopathology is considered the most appropriate framework for biological research and a plea is made for a two-tier diagnostic system of psychiatric disorders. Tier one comprises the nosological diagnosis, and tier two a detailed depiction of the component psychological dysfunctions. Such a two-tier diagnostic system would bring psychopathology onto a true scientific footing.