The classification of personality disorder: II. The problem of diagnostic criteria

Although operational definitions have led to improved reliability of psychiatric diagnoses generally, this is not the case for personality disorders. It is suggested that this is due to a failure to develop definitions composed of criteria that can be reliably identified. Instead, extensive use is made of traits and other dispositions as criteria for assessing these conditions despite an extensive literature indicating that trait judgements are unreliable. The reasons for the low reliability of trait judgements are discussed, and the use of behavioral criteria is advocated as one way to increase diagnostic reliability. The results of a preliminary investigation show that the reliabilities of clinicians' judgements of the behaviors associated with Schizoid, Histrionic, and Compulsive Personality Disorders are comparable to the reliabilities of their judgements of the traits associated with these conditions. These results support the feasibility of developing behavioral criteria for assessing personality.