Proposal for increasing diagnostic clarity in research and clinical practice by renaming and reframing atypical anorexia nervosa as "Restrictive Eating Disorder" (RED)

Guidelines for Rigorous and Reproducible Research on Other Specified Feeding or Eating Disorder: Commentary on Dang et al. (2024)

Dang et al.'s review concludes that atypical anorexia nervosa (atypical AN), purging disorder (PD), and night eating syndrome (NES) are clinically significant and severe eating disorders (EDs). However, findings are unlikely to alter their status in future editions of the DSM due to limitations in the literature to date. Guidelines are offered to promote rigorous and reproducible research on other specified feeding or eating disorder OSFED. First, published research diagnostic criteria for atypical AN, PD, and NES should be consistently used to ensure findings across studies reflect the same conditions. Second, operational definitions are recommended for "recurrent" as at least twice within a 3-month period, minimum duration as at least 1 month, and "significant weight loss" as >5% BMI reduction within 1 month. Third, Thomas's and Gydus's trumping scheme for differential diagnosis of OSFED subcategories is endorsed but should prioritize identifying treatment targets based on medical morbidity over mirroring existing diagnostic algorithms. Fourth, a systematic approach for establishing clinical significance is recommended that explicitly notes medical risk associated with malnutrition, purging and nonpurging behaviors, and relevance of marked distress related to binge eating and body image disturbance. Adoption of these guidelines will facilitate necessary research on clinical utility.

Identification of State Markers in Anorexia Nervosa: Replication and Extension of Inflammation-Associated Biomarkers Using Multiplex Profiling

Background

Proteomics offers potential for detecting and monitoring anorexia nervosa (AN) and its variant, atypical AN (atyp-AN). However, research has been limited by small protein panels, a focus on adult AN, and lack of replication.

Methods

In this study, we performed Olink multiplex profiling of 92 inflammation-related proteins in females with AN/atyp-AN (n = 64), all of whom were ≤90% of expected body weight, and age-matched healthy control individuals (n = 44).

Results

Five proteins differed significantly between the primary AN/atyp-AN group and the healthy control group (lower levels: HGF, IL-18R1, TRANCE; higher levels: CCL23, LIF-R). The expression levels of 3 proteins (lower IL-18R1, TRANCE; higher LIF-R) were uniquely disrupted in participants with AN in our primary model. No unique expression levels emerged for atyp-AN. In the total sample, 12 proteins (ADA, CD5, CD6, CXCL1, FGF-21, HGF, IL-12B, IL18, IL-18R1, SIRT2, TNFSF14, TRANCE) were positively correlated with body mass index and 5 proteins (CCL11, FGF-19, IL8, LIF-R, OPG) were negatively correlated with body mass index in our primary models.

Conclusions

Our results replicate the results of a previous study that demonstrated a dysregulated inflammatory status in AN and extend those results to atyp-AN. Of the 17 proteins correlated with body mass index, 11 were replicated from a previous study that used similar methods, highlighting the promise of inflammatory protein expression levels as biomarkers of AN disease monitoring. Our findings underscore the complexity of AN and atyp-AN by highlighting the inability of the identified proteins to differentiate between these 2 subtypes, thereby emphasizing the heterogeneous nature of these disorders.

Is there a basis for a weight cut-off point? A large-scale investigation of atypical anorexia and anorexia nervosa subtypes among patients at a residential treatment centre

OBJECTIVE

There is debate surrounding how to differentiate between anorexia nervosa (AN) and atypical AN (atypAN) as diagnostic entities, and whether a distinction based on BMI is warranted. Better understanding eating disorder (ED) and emotional symptoms across atypAN and AN subtypes [AN-restricting (AN-R), AN-binge/purge (AN-BP)], with and without controlling for BMI, can elucidate how atypAN differs from AN subtypes and whether there is a basis for a BMI cut-off.

METHODS

1810 female patients at an ED treatment centre completed intake surveys. ANCOVAs assessed differences across AN-R (n = 853), AN-BP (n = 726), and atypAN (n = 231) groups on ED, depressive, and anxiety symptoms, anxiety sensitivity, experiential avoidance, and mindfulness, with and without controlling for BMI.

RESULTS

Relative to AN-R, atypAN and AN-BP groups endorsed significantly higher ED and depressive symptoms, anxiety sensitivity, experiential avoidance, and significantly lower mindfulness (all p < 0.001), but atypAN and AN-BP groups did not differ from one another. When controlling for BMI, all previously significant differences between atypAN and AN-R did not remain significant.

CONCLUSION

Individuals with atypAN who have a higher BMI experience more pronounced ED and emotional symptoms, suggesting that relying solely on BMI as a marker of illness severity may be problematic.

There is nothing as inconsistent as the OSFED diagnostic criteria

Atypical anorexia nervosa (AAN), purging disorder (PD), night eating syndrome (NES), and subthreshold bulimia nervosa and binge-eating disorder (Sub-BN/BED) are the five categories that comprise the 'Other Specified Feeding or Eating Disorder' (OSFED) category in the Diagnostic and Statistical Manual for Mental Disorders (DSM-5). In this review, we examine problems with the diagnostic criteria that are currently proposed for the five OSFED types. We conclude that the existing diagnostic criteria for OSFED are deficient and fall short of accurately describing the complexity and individuality of those with these eating disorders (EDs). Therefore, to enhance the quality of life of people with OSFED, diagnostic criteria for the condition should be applied uniformly in clinical and research settings.

Dissecting the biology of feeding and eating disorders

Feeding and eating disorders (FEDs) are heterogenous and characterized by varying patterns of dysregulated eating and weight. Genome-wide association studies (GWASs) are clarifying their underlying biology and their genetic relationship to other psychiatric and metabolic/anthropometric traits. Genetic research on anorexia nervosa (AN) has identified eight significant loci and uncovered genetic correlations implicating both psychiatric and metabolic/anthropometric risk factors. Careful explication of these metabolic contributors may be key to developing effective and enduring treatments for devastating, life-altering, and frequently lethal illnesses. We discuss clinical phenomenology, genomics, phenomics, intestinal microbiota, and functional genomics and propose a path that translates variants to genes, genes to pathways, and pathways to metabolic outcomes to advance the science and eventually treatment of FEDs.

Comparisons between atypical anorexia nervosa and anorexia nervosa: Psychological and comorbidity patterns

OBJECTIVE

Literature comparing "atypical" anorexia nervosa (atypical AN) and anorexia nervosa (AN) suggests these diagnoses share significant similarities in eating disorder (ED) pathology and psychiatric comorbidities. This study evaluated potential differences in ED pathology, psychiatric comorbidity, associated mechanisms (i.e., ED fears and perfectionism), and demographic factors (i.e., ethnicity and age) between individuals with atypical AN and AN.

METHOD

Data from seven protocols were combined for a total 464 individuals diagnosed with atypical AN (n = 215) or AN (n = 249). Between-group differences in ED severity and behaviors, psychiatric comorbidities, ED fears, perfectionism, and demographic factors were assessed using t-tests, Wilcoxon rank-sum tests, and Fisher's exact test.

RESULTS

Participants with atypical AN reported higher levels of overvaluation of weight and shape than those with AN. Participants with AN scored higher on food-related fears (anxiety about eating, food avoidance behaviors, and feared concerns) and fears of social eating, as well as obsessive-compulsive symptoms. Participants with AN were more likely to identify as Asian or Pacific Islander. No other statistically significant differences were found between groups for overall ED severity, ED behaviors, psychiatric comorbidities, general ED fears, perfectionism, or demographic factors.

DISCUSSION

Overall, results support previous literature indicating limited differences between individuals with atypical AN and AN, though individuals with atypical AN reported more overvaluation of weight and shape and those with AN reported higher food and social eating fears and obsessive-compulsive symptoms. Relatively few overall differences between atypical AN and AN highlight the importance of exploring dimensional conceptualizations of AN as an alternative to the current categorical conceptualization.

PUBLIC SIGNIFICANCE

This study assessed differences among individuals with atypical anorexia nervosa and anorexia nervosa in eating disorder severity and behaviors, comorbid psychiatric diagnoses, associated mechanisms, and demographic factors. Few differences emerged, though participants with atypical anorexia nervosa reported more overvaluation of weight and shape, while those with anorexia nervosa reported more food and social eating fears and higher obsessive-compulsive symptoms. Results support exploration of these diagnoses as a spectrum disorder.

Predictors of psychopathology response in atypical anorexia nervosa following inpatient treatment: A propensity score matching study of weight suppression and weight loss speed

INTRODUCTION

This study examines weight suppression (WS) and weight loss speed (WLS) in atypical anorexia nervosa (AN) and its implications for treatment outcomes, compared to people with AN and bulimia nervosa (BN).

METHOD

A mixed cross-sectional and prospective design was employed, assessing WS and WLS in people with atypical AN, AN, and BN. Participants were matched for age, gender, age of onset, and disorder duration. Clinical measurements and eating disorders questionnaire (EDE-Q) scores were employed to evaluate the response to treatment.

RESULTS

Individuals with atypical individuals exhibited WS patterns similar to AN, distinct from BN. Rapid WLS predicted clinical responses in atypical AN and BN, underscoring its treatment relevance. Atypical AN showed higher eating psychopathology scores than AN or BN, emphasizing the need for a reframed diagnosis.

DISCUSSION

Understanding atypical AN's connection to restrictive behaviors and weight loss informs screening, assessment, and treatment practices. Recognition of atypical AN's severity and adoption of tailored approaches are essential for recovery. This study highlights the significance of WS and WLS in atypical AN treatment outcomes, offering insights into clinical practice and care. The proposal to reframe atypical AN as a restrictive eating disorder emphasizes its clinical relevance.

PUBLIC SIGNIFICANCE STATEMENT

The phenomenon of weight suppression, involving the discrepancy between past highest weight and current weight, has garnered attention due to cultural pressures emphasizing fitness and appearance. This study focuses on its implications in atypical anorexia nervosa, aiming to uncover the relationship between WS, its speed, and treatment outcomes. The investigation contributes insights into tailored interventions for atypical anorexia nervosa and enriches the understanding of this complex disorder's dynamics.

An examination of adults with atypical anorexia nervosa at admission to treatment at higher levels of care: An attempt to increase diagnostic clarity

OBJECTIVE

Anorexia nervosa (AN) is a serious illness with a high mortality rate and multiple physiological complications. The vague definition of atypical AN allows for subjective interpretation. This retrospective study aimed to focus future research on the operational definition of atypical AN by examining four factors associated with atypical AN at admission to higher level of care treatment.

METHODS

Adults with atypical AN (n = 69) were examined within sample analyses among four groups: (1) >10% versus ≤10% weight loss; (2) weight loss within the previous 3 months versus >3 months; (3) engaging in purging behaviors versus absence of purging behaviors; and (4) endorsing versus not endorsing significant cognitive aspects of AN.

RESULTS

Patients with atypical AN endorsed elevated ED cognitions on the Eating Disorder Examination-Questionnaire and depressive symptoms; a lack of association was found between weight loss severity and weight loss time frame with depressive symptoms, eating concern, and restraint. Purging behavior was associated with a higher expected body weight percentage (%EBW) and dietary restraint, while greater AN cognitions were associated with a higher EBW and weight loss percentage. Few patients demonstrated bradycardia, hypophosphatemia, or amenorrhea.

DISCUSSION

This study demonstrated the severity of ED cognitions and depressive symptoms in this atypical AN sample and provided directions for future studies in the nosology of atypical AN. It may be important to distinguish between individuals with atypical AN who are purging and those who are not. Atypical AN was associated with a low frequency of physiological disturbances.

PUBLIC SIGNIFICANCE

This study provides further clarification regarding the operational definition of atypical AN; currently, a constellation of symptoms under Other Specified Feeding or Eating Disorders. This study was consistent with previous research in reporting severe eating disorder cognitions in adults with atypical AN, and noted the potential importance of distinguishing a purging distinction. A minority of patients in this study had physiological impairments.

Understanding community provider practices in diagnosing and treating atypical anorexia nervosa: A mixed methods study

OBJECTIVE

There is a lack of consensus in defining "significant weight loss" when diagnosing atypical anorexia nervosa (atypical AN) and no guidelines exist for setting target weight (TW). The current study aimed to identify community providers' practices related to the diagnosis of atypical AN and the determination of TW. A secondary aim was to evaluate whether professional discipline impacted "significant weight loss" definitions.

METHOD

A variety of providers (N = 141; 96.4% female) completed an online survey pertaining to diagnostic and treatment practices with atypical AN. Descriptive statistics were computed to characterize provider-based practices and Fisher's exact tests were used to test for differences in diagnostic practices by professional discipline. Thematic analysis was used to examine open-ended questions.

RESULTS

Most (63.97%) providers diagnosed atypical AN in the absence of any weight loss if other AN criteria were met, but doctoral-level psychologists and medical professionals were less likely to do so compared to nutritional or other mental health professionals. Most providers found weight gain was only sometimes necessary for atypical AN recovery. Qualitative responses revealed providers found atypical AN to be a stigmatizing label that was not taken seriously. Providers preferred to use an individualized approach focused on behaviors, rather than weight when diagnosing and treating atypical AN.

DISCUSSION

Lack of diagnostic clarity and concrete treatment guidelines for atypical AN may result in substantial deviations from the DSM-5-TR criteria in real-world practice. Clinically useful diagnostic definitions for restrictive eating disorders and evidence-based treatment guidelines for TW and/or other relevant recovery metrics are needed.

PUBLIC SIGNIFICANCE

The current study found variability in how community providers diagnose and determine target recovery weight for atypical anorexia nervosa (atypical AN). Many providers viewed the diagnosis of atypical AN as stigmatizing and preferred to focus on behaviors, rather than weight. This study underscores the importance of creating a clinically useful diagnostic definition and guidelines for recovery for atypical AN backed by empirical evidence that providers may implement in practice.

Time to revisit the definition of atypical anorexia nervosa

In this special issue, international researchers investigate how atypical anorexia nervosa (atypical AN) differs from anorexia nervosa (AN) and other eating disorders with respect to demographics, psychological and physiological morbidity, as well as treatment course and outcome. Manuscripts in this special issue report that atypical AN is associated with substantial medical and psychological morbidity, and the majority of studies find few differences between atypical AN and AN. While much remains to be learned about the long-term course and treatment response of individuals with atypical AN to psychological and pharmacological interventions, the evidence supports conceptualization of atypical AN as part of a spectrum-based restrictive eating disorder. These findings together with the potentially stigmatizing use of the term "atypical" suggest it may be time to revise the existing definition of atypical AN.

Compensatory eating disorder and full threshold DSM eating disorders: A comparison of eating-disorder-related psychiatric impairment and symptomatology

INTRODUCTION

Compensatory eating disorder (CED) is a newly proposed 'other specified feeding and eating disorder' characterized by recurrent non-purging compensatory behaviors (e.g., compulsive exercise and/or food restriction), overvaluation of weight/shape, the absence of objective binge-eating episodes, and the absence of low weight or recent significant weight loss. This study compared individuals with CED to individuals with anorexia nervosa (AN), bulimia nervosa (BN), or binge-eating disorder (BED) on measures of psychiatric impairment, eating-disorder (ED) symptomatology, and comorbid internalizing disorders.

METHOD

Adults (N = 187) with CED, AN, BN, or BED completed measures of ED-related-psychiatric impairment and ED symptomatology. Structured clinical interviews were administered to assess ED and internalizing-disorder diagnoses.

RESULTS

Linear regression models were fit to compare the CED group to full-threshold ED groups on psychiatric impairment, body dissatisfaction, cognitive restraint, negative attitudes towards obesity, and weight suppression. A chi-square difference test examined group differences on internalizing-disorder prevalence. Results indicated that the CED group had high levels of psychiatric impairment, yet psychiatric impairment was significantly lower in the CED group compared to other groups. The AN group had significantly lower body dissatisfaction than the CED group. Individuals with CED had similar cognitive restraint, negative attitudes towards obesity, internalizing psychopathology, and weight suppression compared to other ED groups.

CONCLUSION

Individuals with CED had substantial ED psychopathology and internalizing-disorder prevalence, comparable to individuals with full-threshold EDs. Individuals with CED had high levels of psychiatric impairment, but their impairment was lower than individuals with full-threshold EDs. Our results indicate that CED is a clinically significant disorder.

Conceptualisation of severe and enduring anorexia nervosa: a qualitative meta-synthesis

BACKGROUND

Severe and enduring anorexia nervosa (SE-AN) is amongst the most impairing of all mental illnesses. Collective uncertainties about SE-AN nosology impacts treatment refinement. Qualitative research, particularly lived experience literature, can contribute to a process of revision and enrichment of understanding the SE-AN experience and further develop treatment interventions. Poor outcomes to date, as evidenced in clinical trials and mortality for people with SE-AN (1 in 20) demonstrate the need for research that informs conceptualisations and novel treatment directions. This interpretative, meta-ethnographic meta-synthesis aimed to bridge this gap.

METHODS

A systematic search for qualitative studies that explored the AN experiences of people with a duration of greater than 3 years was undertaken. These studies included those that encompassed phenomenology, treatment experiences and recovery.

RESULTS

36 papers, comprising 382 voices of SE-AN experiences informed the meta-ethnographic findings. Four higher order constructs were generated through a synthesis of themes and participant extracts cited in the extracted papers: (1) Vulnerable sense of self (2) Intra-psychic processes (3) Global impoverishment (4) Inter-psychic temporal processes. Running across these meta-themes were three cross cutting themes (i) Treatment: help versus harm, (ii) Shifts in control (iii) Hope versus hopelessness. These meta-themes were integrated into conceptualisations of SE-AN that was experienced as a recursive process of existential self-in-relation to other and the anorexia nervosa trap.

CONCLUSIONS

The alternative conceptualisation of SE-AN proposed in this paper poses a challenge to current conceptualisations of AN and calls for treatments to engage with the complex intra and inter-psychic processes of the SE-AN, more fully. In doing so, clinicians and researchers are asked to continue to be bold in testing novel ideas that may challenge our own rigidity and attachment to dominant paradigms to best serve the individual person with SE-AN. The 'global impoverishment of self', found in this synthesis of AN experiences, should inform proposed diagnostic criteria for SE-AN.

Identification of State Markers in Anorexia Nervosa: Replication and Extension of Inflammation Associated Biomarkers Using Multiplex Profiling in Anorexia Nervosa and Atypical Anorexia Nervosa

Proteomics provides an opportunity for detection and monitoring of anorexia nervosa (AN) and its related variant, atypical-AN (atyp-AN). However, research to date has been limited by the small number of proteins explored, exclusive focus on adults with AN, and lack of replication across studies. This study performed Olink Proseek Multiplex profiling of 92 proteins involved in inflammation among females with AN and atyp-AN (N = 64), all < 90% of expected body weight, and age-matched healthy controls (HC; N=44). After correction for multiple testing, nine proteins differed significantly in the AN/atyp-AN group relative to HC group ( lower levels: CXCL1, HGF, IL-18R1, TNFSF14, TRANCE; higher levels: CCL23, Flt3L, LIF-R, MMP-1). The expression levels of three proteins ( lower IL-18R1, TRANCE; higher LIF-R) were uniquely disrupted in females with AN. No unique expression levels emerged for atyp-AN. Across the whole sample, twenty-one proteins correlated positively with BMI (ADA, AXIN1, CD5, CD244, CD40, CD6, CXCL1, FGF-21, HGF, IL-10RB, IL-12B, IL18, IL-18R1, IL6, LAP TGF-beta-1, SIRT2, STAMBP, TNFRSF9, TNFSF14, TRAIL, TRANCE) and six (CCL11, CCL23, FGF-19, IL8, LIF-R, OPG) were negatively correlated with BMI. Overall, our results replicate the prior study demonstrating a dysregulated inflammatory status in AN, and extend these results to atyp-AN (AN/atyp-AN all < 90% of expected body weight). Of the 27 proteins correlated with BMI, 18 were replicated from a prior study using similar methods, highlighting the promise of inflammatory protein expression levels as biomarkers of disease monitoring. Additional studies of individuals across the entire weight spectrum are needed to understand the role of inflammation in atyp-AN.