Purging Disorder: Diagnostic Considerations, Mechanisms, and Treatment Implications

Purging disorder (PD) is a potentially debilitating eating disorder that is characterized by recurrent purging behaviors including self-induced vomiting or misuse of laxatives, diuretics, or other medications to influence shape or weight in the absence of objective binge eating. Evidence is mixed as to whether PD is more, less, or equally severe relative to other eating disorders that involve purging. Some researchers have questioned whether PD should be considered a unique diagnosis at all given the mixed evidence on the specificity of PD compared to other eating disorders. Yet, PD is common with lifetime prevalence rates ranging from 4 to 6%, and up to 7% of patients who present for treatment for an eating disorder having a diagnosis of PD. PD is also associated with a number of medical and psychiatric issues. Both psychological (emotion regulation, body dissatisfaction, trait anxiety, and cognitive restraint) and biological (satiety) factors have been identified as potential mechanisms in the development and maintenance of PD. In comparison to bulimia nervosa (BN) in which purging is used specifically to compensate for food eaten during an objective binge episode, in PD, purging may represent a persistent weight control strategy. Little has been written about whether or how treatment should differ for PD based on this functional distinction. Specific treatments for PD have not been developed and compared to existing evidence-based treatments making it difficult to know if treatment outcomes could be optimized by prioritizing the specific mechanisms (e.g., cognitive restraint, trait anxiety, satiety) that drive purging in PD.