Comparing definitions of purging disorder on point prevalence and associations with external validators

Abstract

Objective-We varied two defining features of Purging Disorder (PD): breadth of "purging" behaviors (purging only [narrow] vs. purging and nonpurging [broad]) and minimum behavioral frequency (once vs. twice per week) to examine their impact on syndrome validity.Method-Survey data from 1736 women and 755 men were used for analyses.Results-PD point prevalence was higher in women versus men, and prevalence was lowest for the narrow definition requiring purging twice per week. The narrow definition was associated with significant psychosocial impairment and increased effect sizes in validation analyses. Changing minimum behavioral frequencies did not impact associations with external validators.Discussion-A broad definition of PD that included any compensatory behavior reduced distinctions between PD and normality. Reducing minimum frequency to once per week did not reduce homogeneity or evidence of syndrome severity. Purging once per week may represent the optimal starting point in defining the central behavioral feature of PD.Keywords purging disorder; EDNOS; classification; diagnostic validity; epidemiology Purging Disorder (PD) is characterized by recurrent purging after normal or small amounts of food among individuals with body image disturbance who are not underweight.1 PD is currently included as an example of an Eating Disorder Not Otherwise Specified (EDNOS) in the DSM-IV-TR,2 but recent research suggests that PD should be considered for inclusion as a separate provisional diagnostic category in need of further study in the DSM-V.3 , 4 Specifically, cross-sectional studies, laboratory research, and latent class analyses suggest that PD is distinct from normality1 , 5 -11 and Bulimia Nervosa. 1 , 5 , 8 , 11 -15 In addition, epidemiological studies indicate that PD affects between 1.1% to 5.3% of women in their lifetimes.7 , 16 Thus, introducing PD in the DSM-V has the potential to move a substantial proportion of individuals from the heterogeneous17 and overpopulated18 EDNOS category to a potentially meaningful diagnosis.Including PD in the DSM-V would facilitate research by providing an official definition for the syndrome. Currently, several different definitions have been used,3 , 4 ranging from a broadly defined syndrome that includes purging and nonpurging compensatory behaviors19 -22 to studies that restrict the term purging disorder to individuals who engage in self-induced vomiting or abuse of laxatives or diuretics. 1 , 8 , 9 , 16 , 23 Further, the minimum frequency of purging behaviors has not been well-defined. While several studies have METHOD ParticipantsUndergraduate men (n = 1200) and women (n = 2400) from a selective northeastern university were randomly selected in the springs of 1982,27 1992,28 and 200226 to complete a survey of health and eating patterns (see original reports for additional recruitment details). Overall, participation rates were high; 72% of women (n = 1736) and 63% of men (n = 755) completed the survey. Participants ranged in age from 16-45 years (M=20.0; SD=...

The validity and clinical utility of purging disorder

“…19 A recent article compared varying definitions of Purging Disorder in terms of resulting point prevalence estimates and evidence of syndrome validity using external validators. 20 Although a narrow definition which required purging through the use of self-induced vomiting, laxative or diuretic abuse to influence weight or shape resulted in the lowest point prevalence (and smallest sample size for analyses), this narrowly defined group demonstrated statistically significant differences from a non-eating disorder group on psychosocial adjustment. Moreover, large effect sizes were found for comparisons of this narrowly defined group and non-eating disorder controls across several external validators.…”

“…In addition, both definitions of Purging Disorder resulted in groups that differed significantly from those without eating disorders on psychosocial adjustment, with nearly equivalent effect sizes. 20 Thus, reducing the minimum purging frequency to once per week did not reduce the homogeneity or clinical significance of the syndrome and allowed more individuals to move from the relatively heterogeneous and uninformative diagnosis of EDNOS to a homogeneous Purging Disorder group.…”

“…To our knowledge, no study has compared individuals with Purging Disorder who have subjective binge episodes to those who do not. However, recent studies that have excluded individuals with any binge eating (subjective or objective) in their definitions of Purging Disorder 15,17,20 suggest that Purging Disorder without subjective binge episodes occurs in 0.6 to 0.8% of women. Thus, requiring subjective binge episodes for a diagnosis of Purging Disorder may leave many individuals who regularly purge for the purpose of weight or shape control in the EDNOS category.…”

“…Current (''point'') prevalence estimates in adult female samples have been quite similar across studies conducted in Australia (0.5%), 3 Canada (0.6%) 17 and in US college samples (0.6% and 0.8%). 15,20 Life-time prevalence estimates have been more variable, ranging from 1.1% in an Italian sample 49 to 5.3% in an Australian sample. 4 Developmental Considerations.…”

Demographic and clinical characteristics of individuals utilizing an internet‐based digital coaching program for recovering from binge eating

“…Our diagnoses needs to be considered tentative given that they were based on self-report and on a shorter time frame (28 days) than would be required for DSM-IV diagnoses. We note that selfreport based diagnoses are not uncommon in largescale studies 10,18,22,23 and that recent studies have used 28-day time frames. 18 Among women, aside from higher levels of restraint reported by those with BN, a variable not used for defining BN in our study, and higher mean BMI among those with BED, no significant differences were found when comparing those with BN versus BED.…”