Personality disorders in a total population twin cohort with eating disorders

Findings regarding the occurrence of personality disorders (PDs) in eating disorders (EDs) have been contradictory. Most previous studies have been clinic-based. The aims of the current study were to assess the prevalence of PD in ED in a population-based twin group and to establish the distribution of PD in three subgroups of ED. A two-step screening and diagnostic study of ED was performed in a large Danish twin population. Axis I and axis II DSM-III-R and DSM-IV ED diagnoses were made on the basis of results obtained at clinical investigations and interviews. Forty-nine percent of the participants with ED had at least one PD, compared to 26% in those with no ED (P <.001). Cluster C PD was the most common type of PD in all subgroups of ED, and cluster B PD was found only in participants with bulimic symptoms. Genetic factors appeared to contribute significantly to the variance of cluster C PD in ED, which was evaluated as a possibly important background factor in ED.