not play as large a role on the overall development of the next edition of the diagnostic manual as suggested by First et al. However, clinical utility concerns have been repeatedly raised as a major reason for retaining the existing personality disorder diagnoses (Benjamin, 1993; Frances, 1993; Shedler & Westen, 2004). Verheul’s critique of the existing literature is accurate in its conclusion that there have, as yet, been very few systematic studies assessing the clinical utility of a dimensional classification of personality disorder, and certainly no studies that attempt to address the concerns raised by First et al., Rounsaville et al. (2002), and others.
Consider, for example, the five-factor model (FFM). There is a substantial amount of research supporting its reliability and validity as a dimensional model of personality structure (Mullins-Sweatt & Widiger, in press) and quite a number of studies have suggested that the existing categorical diagnoses can be understood as maladaptive variants of the domains and facets of the FFM (Livesley, 2001-a; Saulsman & Page, 2004; Widiger & Costa, 2002). However, there have been only four studies to date that have even examined the ability of practicing clinicians to use the FFM (i.e., Blais, 1997; Samuel & Widiger, 2004; Sprock, 2002, 2003).
Blais (1997) asked 100 clinicians to describe one of their clients who carried a primary diagnosis of personality disorder with respect to the five domains of the FFM and the 10 DSM-IV personality disorders. Blais found extensive agreement among the clinicians’ FFM ratings for each particular DSM personality disorder. Blais concluded, “despite the concerns raised by Benjamin (1993), these data suggest that clinicians can meaningfully apply the FFM to their patients and that the FFM of personality has utility for improving our understanding of the DSM personality disorders” (p. 392).