Diagnostic approaches to schizotypal personality disorder: a historical perspective.

The goal of this article is to provide a historical perspective on the DSM-III concept of schizotypal personality disorder. It is argued that two major traditions have influenced our conceptualization of this diagnostic entity. The first or familial approach emphasizes the characteristic traits found in the deviant but nonpsychotic relatives of schizophrenics. The second or clinical approach focuses on patients who appear to demonstrate the fundamental symptoms of schizophrenia without psychotic symptoms or severe personality deterioration. A review of these two traditions concludes that while similar in some regards, they also differ in important ways in their views on the characteristics of the true "schizotype." The impact of these two traditions is then traced through the Danish Adoption Studies of Kety et al. to the development of the DSM-III criteria for schizotypal personality by Spitzer, Endicott, and Gibbon. Finally, the article reviews recent studies on the validity of specific criteria for schizotypal personality disorder (SPD) and reassesses the conceptual issue about the nature of the relationship of SPD to schizophrenia on the one hand and to other personality disorders on the other.