Gender bias in diagnostic criteria for personality disorders: an item response theory analysis.

The issue of gender bias with regard to Diagnostic and Statistical Manual of Mental Disorders (DSM) personality disorder criteria has been controversial and widely debated. The current DSM (4th ed., text revision; DSM–IV–TR; American Psychiatric Association, 2000) makes no explicit statement regarding gender bias among the personality disorders (PDs), but it does suggest that six disorders (antisocial, narcissistic, obsessive-compulsive, paranoid, schizotypal, schizoid) are more frequently found in men. Three others (borderline, histrionic, dependent) are presumably more frequent in women. There are many ways to interpret differential prevalence rates as a function of gender (Corbitt & Widiger, 1995). Some critics have argued that they are an artifact of gender bias (Caplan, 1995; Kaplan, 1983; Walker, 1994). In other words, the PD criteria assume unfairly that stereotypical female characteristics are pathological. Widiger (1998) described six ways in which gender bias may be related to differential prevalence rates: biases in diagnostic constructs, diagnostic thresholds, sampling of the population, application of the diagnostic criteria, assessment instruments, and diagnostic criteria. Some evidence does support a link between diagnostic constructs and gender stereotypes (Rienzi & Scrams, 1991; Slavney, 1984), but diagnostic thresholds for PDs do not seem to be biased (Funtowicz & Widiger, 1995, 1999). Greater support has emerged for the argument that assessment instruments may contain gender bias, and clinicians may behave in a biased way when they apply PD criteria to men and women. Lindsay and Widiger (1995) found that items in several of the most widely used PD instruments are biased in the sense that they are endorsed more easily by men than by women. Further, research has shown that clinicians do not apply certain PD diagnoses (i.e., histrionic and antisocial) equally to men and women (Garb, 1997). The evidence is mixed with regard to diagnostic bias in the criteria themselves. Widiger (1998) defined criteria bias as the likelihood that men and women may exhibit the disorder differently because PD criteria include gender-related symptomatology. Anderson, Sankis, and Widiger (2001) conducted a study of potential sources of gender bias in the diagnostic criteria using two samples of professional clinicians from Division 12 of the American Psychological Association. In the first study, 181 clinical psychologists completed measures of statistical infrequency (i.e., how unlikely it would be to find that criterion in a male or female patient) and pathology (i.e., to what extent the presence of that criterion would indicate maladaptive behavior). Measures were collected for DSM–IV–TR antisocial, narcissistic, histrionic, and borderline criteria. Significant differences were found for the infrequency ratings with regard to the antisocial, histrionic, and narcissistic criteria sets (in sum, 14 of the 32 diagnostic criteria). Results were not significant for pathology ratings of the four criteria sets (and were significant for only three of the 32 criteria at α = .05). The second study was almost identical, except that criteria from the antisocial, histrionic, narcissistic, and dependent disorders were examined. Results were largely consistent with those of the first study. Infrequency was statistically different for the antisocial, narcissistic, and dependent criteria, but there were no differences by gender for pathology ratings on any of the four criteria sets. The authors concluded that the diagnostic criteria from these five disorders “have differential sex prevalence rates…. but professional clinicians who apply these diagnostic criteria to men and women do not perceive the diagnostic criteria as having different implications for maladaptivity or impairment” (Anderson et al., 2001, p. 667). Only one study has examined differential prevalence ratings on all DSM–IV–TR criteria as reported by participants using questionnaires (Morey, Warner, & Boggs, 2002). Gender differences reached significance for 9 of the 79 criteria. As in previous studies (Anderson et al., 2001; Sprock, Crosby, & Nielsen, 2001), participants were also asked to provide pathology ratings (e.g., “a man with this characteristic would have much more trouble functioning than a woman with this characteristic” and vice versa). Results were largely nonsignificant, but when a criterion was viewed as more problematic for one gender, it also tended to be more prevalent in that gender. Morey et al. (2002) concluded that extremes of sex-typed behaviors are viewed by others as most problematic, and “personality problems simply tend to manifest differently in men and women” (p. 62). Gender bias in the diagnostic criteria for borderline, schizotypal, avoidant, and obsessive-compulsive PDs has also been studied by Boggs et al. (2005). Using data from the Collaborative Longitudinal Personality Disorders Study, these investigators examined relations among diagnostic criteria (measured using semistructured diagnostic interviews) and levels of functional impairment in male and female patients. The data indicated relatively little evidence of gender bias. In other words, specific diagnostic criteria were associated with equivalent levels of impairment in men and women. In the current study, we investigated whether gender bias is associated with diagnostic criteria for PDs using differential item functioning (DIF), a psychometric method for evaluating whether a construct is expressed equivalently across different groups. Because it is assessed within an item response theory (IRT) framework, DIF can determine whether a person's response on an item (in this case, a PD criterion) depends on both his or her trait level (level of personality pathology) and group membership (gender). In other words, given the same level of personality pathology, are men more likely than women to endorse a PD criterion (or vice versa)?