An empirical study of the typology of bulimic symptoms in young Portuguese women

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.

Empirically derived classes of eating pathology in male and female college students

BACKGROUND

The empirical structure of eating disorder (ED) pathology has often been studied in female, clinical samples, leaving questions about the structure of ED pathology in males and nonclinical samples.

METHOD

A latent class analysis was performed on data combined from two different studies (N = 1,751) using the behavioral items in the Eating Disorder Examination Questionnaire (EDE-Q; binge eating, self-induced vomiting, laxative use, and excessive exercise), with the addition of an item representing restraint. Validation analyses examined weight, shape, and eating concern among the classes.

RESULTS

Three similar classes emerged for both the men and women's models: very low ED behaviors, binge eating, and high ED behaviors.

DISCUSSION

These results suggest that binge eating occurs within the context of lower symptom and higher symptom presentations, and that the empirical structure of ED symptoms does not differ in men and women in the nonclinical population. Further research is needed to clarify whether ED phenotypes differ in men and women.

Do recognizable lifetime eating disorder phenotypes naturally occur in a culturally asian population? A combined latent profile and taxometric approach

BACKGROUND

We examined whether empirically derived eating disorder (ED) categories in Hong Kong Chinese patients (N = 454) would be consistent with recognizable lifetime ED phenotypes derived from latent structure models of European and American samples.

METHOD

We performed latent profile analysis (LPA) using indicator variables from data collected during routine assessment, and then applied taxometric analysis to determine whether latent classes were qualitatively versus quantitatively distinct.

RESULTS

Latent profile analysis identified four classes: (i) binge/purge (47%); (ii) non-fat-phobic low-weight (34%); (iii) fat-phobic low-weight (12%); and (iv) overweight disordered eating (6%). Taxometric analysis identified qualitative (categorical) distinctions between the binge/purge and non-fat-phobic low-weight classes, and also between the fat-phobic and non-fat-phobic low-weight classes. Distinctions between the fat-phobic low-weight and binge/purge classes were indeterminate.

CONCLUSION

Empirically derived categories in Hong Kong showed recognizable correspondence with recognizable lifetime ED phenotypes. Although taxometric findings support two distinct classes of low weight EDs, LPA findings also support heterogeneity among non-fat-phobic individuals.

Affect regulation and purging: An ecological momentary assessment study in purging disorder

Research suggests that affect may play an important role in the propensity to purge among women with purging disorder (PD). However, prior work has been constrained to cross-sectional or laboratory designs, which impact temporal interpretations and ecological validity. This study examined negative affect (NA) and positive affect (PA) in triggering and maintaining purging in PD using ecological momentary assessment. Women with PD (N = 24) made multiple daily ratings of affect and behavior for 2 weeks. Multilevel models examined associations between affect and purging at different levels of analysis, including a novel analytic approach to address the specificity of changes in affect relative to purging behavior by comparing trajectories of change on purge versus nonpurge days. For trajectories of affect over time, NA increased before purging and decreased following purging on purge days; however, only the decrease in NA following purging was significantly different from the trajectory of NA on nonpurge days. Conversely, PA failed to increase before purging on purge days compared with a matched time-point on nonpurge days. These findings suggest unique roles of PA in triggering and NA in maintaining purging in PD and support models in which purging functions to regulate affect. For comparisons of ratings before and after purging, NA increased and PA decreased after purging, highlighting how different analytic strategies produce different findings requiring integration into affect regulation models. These data provide insight into why women with PD purge after consuming normal amounts of food, a crucial first step for developing effective interventions.

A latent class analysis to empirically describe eating disorders through developmental stages

OBJECTIVES

The current standards for classifying eating disorders were primarily informed by adult, clinical study populations, while it is unknown whether an empirically based classification system can be supported across preadolescence through young adulthood. Using latent class analyses, we sought to empirically classify disordered eating in females from preadolescence to young adulthood, and assess the association between classes and adverse outcomes.

METHOD

Latent class models were fit using observations from the 9,039 girls participating in the growing up today study, an on-going cohort following participants annually or biennially since 1996 when they were ages 9-14 years. Associations between classes and drug use, binge drinking, and depressive symptoms were assessed using generalized estimating equations.

RESULTS

Across age groups, there was evidence of six classes: a large asymptomatic class, a class characterized by shape/weight concerns, a class characterized by overeating without loss of control, and three resembling full and subthreshold binge eating disorder, purging disorder, and bulimia nervosa. Relative prevalences of classes varied across developmental stages, with symptomatic classes increasing in prevalence with increasing age. Symptomatic classes were associated with concurrent and incident drug use, binge drinking, and high depressive symptoms.

DISCUSSION

A classification system resembling broader definitions of DSM-5 diagnoses along with two further subclinical symptomatic classes may be a useful framework for studying disordered eating among adolescent and young adult females.

Response patterns on interview and questionnaire versions of the Eating Disorder Examination and their impact on latent structure analyses

OBJECTIVE

The purpose of this investigation was to compare the latent structures of the interview (EDE) and questionnaire (EDE-Q) versions of the Eating Disorder Examination.

METHODS

Participants were 280 children, adolescents, and young adults seeking eating disorder treatment. Two separate latent structure analyses (LSAs) were conducted; one used variables from the EDE as indicators and the other used the corresponding variables from the EDE-Q as indicators.

RESULTS

The EDE and EDE-Q models both yielded four-class solutions. Three of the four classes from the EDE-Q model demonstrated moderate to high concordance with their paired class from the EDE model. Using the EDE-Q to detect the EDE, the sensitivity and specificity of measuring certain classes varied from poor (18.6%) to excellent (93.7%). The overall concordance was moderate (κ=.49).

DISCUSSION

These data suggest that LSAs using the EDE and EDE-Q may be directly compared; however, differences between results may represent inconsistencies in response patterns rather than true differences in psychopathology.

A Monte Carlo investigation of factors influencing latent class analysis: an application to eating disorder research

OBJECTIVE

Latent class analysis (LCA) has frequently been used to identify qualitatively distinct phenotypes of disordered eating. However, little consideration has been given to methodological factors that may influence the accuracy of these results.

METHOD

Monte Carlo simulations were used to evaluate methodological factors that may influence the accuracy of LCA under scenarios similar to those seen in previous eating disorder research.

RESULTS

Under these scenarios, the aBIC provided the best overall performance as an information criterion, requiring sample sizes of 300 in both balanced and unbalanced structures to achieve accuracy proportions of at least 80%. The BIC and cAIC required larger samples to achieve comparable performance, while the AIC performed poorly universally in comparison. Accuracy generally was lower with unbalanced classes, fewer indicators, greater or nonrandom missing data, conditional independence assumption violations, and lower base rates of indicator endorsement.

DISCUSSION

These results provide critical information for interpreting previous LCA research and designing future classification studies.

Latent class analysis of eating and impulsive behavioral symptoms in Taiwanese women with bulimia nervosa

OBJECTIVE

The implications of impulsivity in its relationship with binge-eating or purging behaviors remain unclear. This study examined the patterns of eating behaviors and co-morbid impulsive behaviors in individuals with bulimia nervosa n optimally homogeneous classes using latent class analysis (LCA).

METHODS

All participants (n=180) were asked to complete a series of self-reported inventories of impulsive behaviors and other psychological measures. Information regarding the lifetime presence of symptoms of eating disorder was assessed by clinical interviews. LCA was conducted using eating disorder symptoms, impulsive behaviors, and the number of purging methods.

RESULTS

Three latent classes of bulimic women were identified. These were women who exhibited relatively higher rates of purging, symptoms of impulsive behavior, and multiple purging methods (17.8%), women who used no more than one purging method with a low occurrence of impulsive behavior (41.7%), and women who showed higher rates of purging behaviors and the use of multiple purging methods with a low rate of impulsive behavior (41.7%). The impulsive sub-group had comparable severity of eating-related measures, frequency of binge-eating, and higher levels of general psychopathology than that of the other two sub-groups.

CONCLUSION

This study provides empirical support for the existence of an impulsive subgroup with distinctive features among a non-Western group of BN patients. This study also suggests that mechanisms other than impulse dysregulation may exist for the development of binge-eating and purging behaviors in bulimia nervosa patients, or the mechanisms contributing to binge-eating and impulsive behaviors may be different.

Clinical significance and distinctiveness of purging disorder and binge eating disorder

OBJECTIVE

In the DSM-IV, individuals with binge eating disorder (BED) and those with purging disorder (PD) receive a diagnosis of eating disorder not otherwise specified (EDNOS), suggesting no meaningful differences between clinical presentations. This article compares PD and BED on eating disorder severity and comorbid disorders.

METHOD

Individuals with PD (n = 33), DSM-IV BED (n = 23 with BMI >30 kg/m(2) , and n = 18 with BMI between 18.5 and 26.5 kg/m(2) ), and noneating disorder controls (n = 35) completed SCID-I interviews and questionnaires.

RESULTS

Eating disorder groups reported significantly greater depression, body dissatisfaction, and dietary restraint and more Axis I disorders compared with controls. Compared with both the obese and normal weight BED groups, PD reported significantly greater dietary restraint and body dissatisfaction. Compared with obese BED, PD reported lower prevalence of impulse control disorders.

DISCUSSION

Findings support differentiating among EDNOS based on behavioral presentation in both research and future nosological schemes such as the DSM-V.

A latent profile analysis of the typology of bulimic symptoms in an indigenous Pacific population: evidence of cross-cultural variation in phenomenology

BACKGROUND

Previous efforts to derive empirically based eating disorder (ED) typologies through latent structure modeling have been limited by the ethnic and cultural homogeneity of their study populations and their reliance on DSM-IV ED signs and symptoms as indicator variables.

METHOD

Ethnic Fijian schoolgirls (n=523) responded to a self-report battery assessing ED symptoms, herbal purgative use, co-morbid psychopathology, clinical impairment, cultural orientation, and peer influences. Participants who endorsed self-induced vomiting or herbal purgative use in the past 28 days (n=222) were included in a latent profile analysis (LPA) to identify unique subgroups of bulimic symptomatology.

RESULTS

LPA identified a bulimia nervosa (BN)-like class (n=86) characterized by high rates of binge eating and self-induced vomiting, and a herbal purgative class (n=136) characterized primarily by the use of indigenous Fijian herbal purgatives. Both ED classes endorsed greater eating pathology and general psychopathology than non-purging participants, and the herbal purgative class endorsed greater clinical impairment than either the BN-like or non-purging participants. Cultural orientation did not differ between the two ED classes.

CONCLUSIONS

Including study populations typically under-represented in mental health research and broadening the scope of relevant signs and symptoms in latent structure models may increase the generalizability of ED nosological schemes to encompass greater cultural diversity.

Stability and change in patterns of concerns related to eating, weight, and shape in young adult women: a latent transition analysis

Although college women are known to be at high risk for eating-related problems, relatively little is known about how various aspects of concerns related to eating, weight, and shape are patterned syndromally in this population. Moreover, the extent to which various patterns represent stable conditions or transitory states during this dynamic period of development is unclear. The present study used latent class and latent transition analysis (LCA/LTA) to derive syndromes of concerns related to eating, weight, and shape and movement across these syndromes in a sample of 1,498 women ascertained as first-time freshmen and studied over 4 years. LCA identified 5 classes characterized by (a) no obvious pathological eating-related concerns (prevalence: 28%-34%); (b) a high likelihood of limiting attempts (prevalence: 29%-34%); (c) a high likelihood of overeating and binge eating (prevalence: 14%-18%); (d) a high likelihood of limiting attempts and overeating or binge eating (prevalence: 14%-17%); and (e) pervasive bulimic like concerns (prevalence: 6%-7%). Membership in each latent class tended to be stable over time. When movement occurred, it tended to be to a less severe class. These findings indicate that there are distinct, prevalent, and relatively stable forms of eating-related concerns in college women.

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

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.

Diagnostic classification of eating disorders in children and adolescents: how does DSM-IV-TR compare to empirically-derived categories?

OBJECTIVE

The purpose of this study was to empirically derive eating disorder phenotypes in a clinical sample of children and adolescents using latent profile analysis (LPA), and to compare these latent profile (LP) groups to the DSM-IV-TR eating disorder categories.

METHOD

Eating disorder symptom data collected from 401 youth (aged 7 through 19 years; mean 15.14 +/- 2.35 years) seeking eating disorder treatment were included in LPA; general linear models were used to compare LP groups to DSM-IV-TR eating disorder categories on pretreatment and outcome indices.

RESULTS

Three LP groups were identified: LP1 (n = 144), characterized by binge eating and purging ("Binge/purge"); LP2 (n = 126), characterized by excessive exercise and extreme eating disorder cognitions ("Exercise-extreme cognitions"); and LP3 (n = 131), characterized by minimal eating disorder behaviors and cognitions ("Minimal behaviors/cognitions"). Identified LPs imperfectly resembled DSM-IV-TR eating disorders. LP1 resembled bulimia nervosa; LP2 and LP3 broadly resembled anorexia nervosa with a relaxed weight criterion, differentiated by excessive exercise and severity of eating disorder cognitions. The LP groups were more differentiated than the DSM-IV-TR categories across pretreatment eating disorder and general psychopathology indices, as well as weight change at follow-up. Neither LP nor DSM-IV-TR categories predicted change in binge/purge behaviors. Validation analyses suggest these empirically derived groups improve upon the current DSM-IV-TR categories.

CONCLUSIONS

In children and adolescents, revisions for DSM-V should consider recognition of patients with minimal cognitive eating disorder symptoms.

The validity and clinical utility of purging disorder

OBJECTIVE

To review evidence of the validity and clinical utility of Purging Disorder and examine options for the Diagnostic and Statistical Manual of Mental Disorders fifth edition (DSM-V).

METHOD

Articles were identified by computerized and manual searches and reviewed to address five questions about Purging Disorder: Is there "ample" literature? Is the syndrome clearly defined? Can it be measured and diagnosed reliably? Can it be differentiated from other eating disorders? Is there evidence of syndrome validity?

RESULTS

Although empirical classification and concurrent validity studies provide emerging support for the distinctiveness of Purging Disorder, questions remain about definition, diagnostic reliability in clinical settings, and clinical utility (i.e., prognostic validity).

DISCUSSION

We discuss strengths and weaknesses associated with various options for the status of Purging Disorder in the DSM-V ranging from making no changes from DSM-IV to designating Purging Disorder a diagnosis on equal footing with Anorexia Nervosa and Bulimia Nervosa.

The relationship between eating disorder not otherwise specified (EDNOS) and officially recognized eating disorders: meta-analysis and implications for DSM

Eating disorder not otherwise specified (EDNOS) is the most prevalent eating disorder (ED) diagnosis. In this meta-analysis, the authors aimed to inform Diagnostic and Statistical Manual of Mental Disorders revisions by comparing the psychopathology of EDNOS with that of the officially recognized EDs: anorexia nervosa (AN), bulimia nervosa (BN), and binge eating disorder (BED). A comprehensive literature search identified 125 eligible studies (published and unpublished) appearing in the literature from 1987 to 2007. Random effects analyses indicated that whereas EDNOS did not differ significantly from AN and BED on eating pathology or general psychopathology, BN exhibited greater eating and general psychopathology than EDNOS. Moderator analyses indicated that EDNOS groups who met all diagnostic criteria for AN except for amenorrhea did not differ significantly from full syndrome cases. Similarly, EDNOS groups who met all criteria for BN or BED except for binge frequency did not differ significantly from full syndrome cases. Results suggest that EDNOS represents a set of disorders associated with substantial psychological and physiological morbidity. Although certain EDNOS subtypes could be incorporated into existing Diagnostic and Statistical Manual of Mental Disorders (4th ed.; American Psychiatric Association, 1994) categories, others-such as purging disorder and non-fat-phobic AN-may be best conceptualized as distinct syndromes. (PsycINFO Database Record (c) 2009 APA, all rights reserved).