A cluster analysis of purging disorder: Validation analyses with eating disorder symptoms, general psychopathology and personality.

Objectives: To assess the natural grouping of Purging Disorder (PD) patients based on purging symptomatology and to evaluate the derived classes (a) against each other and (b) to a control group on a range of clinical and psychological measures.

Method: Participants included 223 PD women consecutively admitted to a tertiary ED treatment centre and 822 controls. Purging behaviours (self-induced vomiting, laxative and diuretic use) were used as indicators, while the EDI-2 (ED symptoms), the SCL-90-R (general psychopathology), and the TCI-R (personality traits) were used as validators.

Results: Three distinct PD clusters emerged: Cluster 1 (only self-induced vomiting), Cluster 2 (self-induced vomiting and laxative use) and Cluster 3 (all purging methods). Significant differences between Cluster 1 and Cluster 3 were found for the EDI-2 drive for thinness and perfectionism subscales, and the TCI-persistence scale. All clusters differed significantly from the controls on all the EDI-2 and the SCL-90-R scales, but findings for the TCI-R scales were less consistent.

Conclusions: This study adds to a growing literature on the validity and distinctiveness of PD and provides evidence of dimensional symptom differences amongst PD clusters.