Personality disorder--not otherwise specified evidence of validity and consideration for DSM-5.

Personality disorder-not otherwise specified (PD-NOS) has received little study despite being a very prevalent diagnosis of personality disorder (PD). Although some studies suggest that PD-NOS is intermediate in severity between subjects with, and without, formal PD, studies examining a comprehensive set of measures and control subjects have not been reported. Nearly 800 subjects were studied with semi-structured diagnostic interviews and with a variety of measures of temperament, character, and specific dimensions of personality and behavior. The subjects were divided into healthy controls (n = 176), Axis I controls (n = 87), PD subjects (n = 344) and PD-NOS subjects (n = 177). Subjects who met General Diagnostic Criteria for Personality Disorder (GDCPD), but not criteria for any one, specific PD, were designated as PD-NOS. On nearly all measures, PD-NOS differed from Healthy and from Axis I Controls in the direction of more pathology. Although subjects meeting criteria for specific PDs appeared more pathological than PD-NOS, this was always due to severity of PD as reflected by the Structured Interview for the Diagnosis of DSM Personality 4 severity score. When compared with subjects with only one specific PD diagnosis, subjects with PD-NOS did not differ in any way. When diagnosed by GDCPD, subjects with PD-NOS are similar to subjects with specific personality disorders and differ, as expected, from Healthy and Axis I Controls on measures of psychosocial function and on various dimensions of personality and related behavior. Accordingly, PD-NOS by GDCPD is as valid a PD as any other specific PD by DSM criteria.