Personality disorder not otherwise specified: searching for an empirically based diagnostic threshold.

The purpose of this paper is to propose a method for empirically investigating diagnostic criteria for personality disorder not otherwise specified (PDNOS). From a large, nonclinical sample of military recruits and undergraduate students who were screened for personality disorders (PDs), 572 completed the Structured Interview for DSM-IV Personality. Data from the interviewed group were used to identify a diagnostic threshold for PDNOS by comparing those who did (n = 88) and did not (n = 484) qualify for a PD diagnosis. For both groups, subjective distress increased and measures of social and occupational functioning decreased as a function of the number of PD criteria met. A classification and regression tree modeling procedure was applied using self-report scores on measures of mood, anxiety, and personality traits to arrive at probabilities for predicting the presence of a PD diagnosis based on the pattern of reported traits present. These probabilities were then used to derive an empirically based diagnostic threshold for PDNOS. In this sample, the most appropriate threshold for a PDNOS diagnosis appears to be the presence of 10 PD criteria for a person who does not qualify for a diagnosis of any other specific form of PD. This definition identified 5.5% of the young adults who were interviewed in this study.