Comorbid features in bulimics before and after therapy: are they explained by axis II diagnoses, secondary effects of bulimia, or both?

This study evaluated the extent to which personality disorder (PD) diagnoses drawn in active bulimics explained pretreatment and posttreatment comorbid features, once possible secondary effects of bulimia nervosa (BN) on the mental status were controlled. We used structured interviews to assign axis II diagnoses to 73 DSM-III-R bulimics, and then examined whether or not classification into borderline PD (BPD), other PD (OPD), or no PD (NPD) groups (a) predicted pretreatment and posttreatment differences in comorbid symptoms, and (b) explained the severity of comorbid symptoms independent of effects attributable to BN sequelae. Groups never differed on eating-symptom measures, with all showing satisfactory average improvements over 3 months. However, on pretreatment and posttreatment comorbid symptoms, BPD subjects displayed more depression, reliance on maladaptive defenses, and other pathological features than did other groups. More importantly, after controlling for the effects of possible sequelae of BN on comorbid symptoms at each point in time, a borderline/nonborderline distinction always explained significant residual proportions of variance in comorbid symptoms. These findings suggest that despite tendencies for BN to exacerbate concurrent symptoms, axis II diagnoses remain meaningful as indicators of comorbid features.