Internal consistency, intercriterion overlap and diagnostic efficiency of criteria sets for DSM-IV schizotypal, borderline, avoidant and obsessive-compulsive personality disorders

Objective: To evaluate performance characteristics of DSM-IV Personality Disorders (PDs) criteria. Method: Six hundred and sixty-eight adults recruited for the Collaborative Longitudinal Personality Disorders Study (CLPS) were assessed with diagnostic interviews. Results: Within-category inter-relatedness was evaluated by Cronbach's alpha and median intercriterion correlations (MIC). Cronbach's alpha ranged from 0.47 to 0.87 (median=0.71); seven of the 10 PDs had alphas greater than 0.70. Between-category criterion overlap was evaluated by 'inter-category' intercriterion correlations between all PD pairs (ICMIC). ICMIC values (median=0.08) were lower than MIC values (median=0.23). Diagnostic efficiency statistics (sensitivity, specificity, positive predictive power and negative predictive power were calculated for schizotypal, borderline, avoidant and obsessive-compulsive PDs. Conclusion: DSM-IV PID criteria sets have some convergent validity and discriminant validity: criteria for individual PDs correlate better with each other than with criteria for other PDs. Diagnostic efficiency statistics provide guidance regarding usefulness of criteria for inclusion or exclusion.