85 What the FFM can do well is explain the diagnostic cooccurrence.73,86,87 For example, Lynam and Widiger indicated that the extent to which the personality check details disorders shared FFM traits explained much of the co-occurrence among the diagnostic categories. They produced FFM profiles for each DSM-IV-TR personality disorder, and then indicated empirically that the extent of overlap among the FFM traits that

defined each disorder accounted for much of their diagnostic co-occurrence. For example, the avoidant and schizoid personality disorders share traits of introversion; dependent and Inhibitors,research,lifescience,medical avoidant share traits of agreeableness; and most of the personality disorders contain a considerable amount of neuroticism. The “overlap among FFM profiles reproduced well the covariation obtained for the schizoid, schizotypal, antisocial, borderline, histrionic, narcissistic, avoidant, Inhibitors,research,lifescience,medical and compulsive personality disorders aggregated across several sets of studies.”73, p410 Poor results were obtained for only one personality disorder, dependent, precisely because its FFM description provided considerably more differentiation from other personality disorders than is in fact found using the DSM-IV-TR criterion sets. Discriminant validity would clearly be better with the

factor-analytically based FFM constructs relative to the Inhibitors,research,lifescience,medical explicitly overlapping syndromes of the DSM-IV-TR. Some of the FFM facets do correlate with other domains Inhibitors,research,lifescience,medical (eg, the angry hostility of neuroticism correlates with antagonism; and the excitement-seeking of extraversion correlates with low conscientiousness), but the five domains of the FFM are much less correlated than the 10 personality disorders (or the three clusters) of the DSM-IV-TR. Samuel Inhibitors,research,lifescience,medical and Widiger88 demonstrated this empirically in a direct comparison of the FFM and DSM-IV-TR models of classification across four methods of assessment: self-report, semistructured interview, peer report, and clinician rating. Gender bias within the personality

disorder nomenclature has been a heated issue for quite some time.89 The differential sex ADP ribosylation factor prevalence rates that have been reported were also difficult to justify in the absence of any theoretical basis for knowing what differential sex prevalence should be obtained. In contrast, the FFM has proved useful in helping to explain and understand gender differences in personality90,91 and can help explain as well the gender differences in personality disorder.92 Lynam and Widiger93 demonstrated that the differential sex prevalence rates obtained for the DSM-IV-TR personality disorders are well explained if these disorders are understood as maladaptive variants of the domains and facets of the FFM.