Diagnostic Criteria for the Borderline and Schizotypal Personality Disorders

Eighty-four inpatients were interviewed to evaluate systematically each of 81 symptoms for the 11 Diagnostic and Statistical Manual of Mental Disorders (DSM-III) personality disorders. The internal consistency and descriptive validity of the borderline and schizotypal symptoms were analyzed by calculating (a) their sensitivity, specificity, positive predictive power, and negative predictive power and (b) their correlation with the diagnoses' cutoff points and total number of symptoms. Despite a 40% overlap of the borderline and schizotypal diagnoses, none of the borderline and only two of the schizotypal symptoms correlated with the other disorder's criteria set. Most symptoms were successful as inclusion tests, but not as exclusion tests. Physically self-damaging acts and impulsivity were successful as both. The schizotypal's social-interpersonal symptoms were less efficient in differentiating schizotypal from borderline than the perceptual-cognitive. Implications of the analyses for a categorical versus dimensional model of classification and for the construction and evaluation of diagnostic criteria are discussed.