New perspectives on the role of biological factors in anorexia nervosa: Brain volume reduction or oxidative stress, which came first?

Anorexia nervosa (AN) is an eating disorder (ED) that has seen an increase in its incidence in the last thirty years. Compared to other psychosomatic disorders, ED can be responsible for many major medical complications, moreover, in addition to the various systemic impairments, patients with AN undergo morphological and physiological changes affecting the cerebral cortex. Through immunohistochemical studies on portions of postmortem human brain of people affected by AN and healthy individuals, and western blot studies on leucocytes of young patients and healthy controls, this study investigated the role in the afore-mentioned processes of altered redox state. The results showed that the brain volume reduction in AN could be due to an increase in the rate of cell death, mainly by apoptosis, in which mitochondria, main cellular organelles affected by a decreased dietary intake, and a highly compromised intracellular redox balance, may play a pivotal role.

Influence of the gut microbiome on appetite-regulating neuropeptides in the hypothalamus: Insight from conventional, antibiotic-treated, and germ-free mouse models of anorexia nervosa.

Recent research highlights the profound impact of the gut microbiome on neuropsychiatric disorders, shedding light on its potential role in shaping human behavior. In this study, we investigate the role of the gut microbiome in appetite regulation using activity-based anorexia (ABA) mouse model of anorexia nervosa (AN) - a severe eating disorder with significant health consequences. ABA was induced in conventional, antibiotic-treated, and germ-free mice. Our results show the clear influence of the gut microbiome on the expression of four orexigenic (neuropeptide Y, agouti-related peptide, melanin-concentrating hormone, and orexin) and four anorexigenic peptides (cocaine- and amphetamine-regulated transcript, corticotropin-releasing hormone, thyrotropin-releasing hormone, and pro-opiomelanocortin) in the hypothalamus. Additionally, we assessed alterations in gut barrier permeability. While variations were noted in germ-free mice based on feeding and activity, they were not directly attributable to the gut microbiome. This research emphasizes that the gut microbiome is a pivotal factor in AN's appetite regulation beyond just dietary habits or physical activity.

Racial, Ethnic, and Sex Differences in Eating Disorder Onset Among U.S. Military Service Members.

Bulimia nervosa (BN) and binge eating disorder (BED) are the most prevalent eating disorders (EDs) among military personnel. Although sex differences are noted in ED prevalence in military and civilian samples, mixed findings have emerged when evaluating racial and ethnic differences. The present study examined independent associations and interactions between sex, race, ethnicity, and probable BED and BN onset. The sample included 91,413 and 96,245 service members from the Millennium Cohort Study for BED and BN analyses, respectively. Up to four datapoints (from 2001-2013) were used to conduct longitudinal complementary log-log regression analyses, as participants were followed until the outcome occurred or until study completion. BN was more likely among women than men, and no sex difference emerged for BED onset. BN was more likely among Hispanic/Latinx, Multiracial, Black, and Asian/Pacific Islander (API) while BED was less likely among Black and API versus non-Hispanic/Latinx White (NHW) service members. Interactions revealed greater likelihood of BN in Hispanic/Latinx service members was driven by men. Additional efforts are needed amongst racially and ethnically diverse groups in preventing and detecting EDs in military personnel. Future intersectionality research could elucidate systemic inequities and other contributing factors to ED onset to inform prevention and treatment efforts.

Targeting the orexin/hypocretin system for the treatment of neuropsychiatric and neurodegenerative diseases: From animal to clinical studies.

Orexins (also known as hypocretins) are neuropeptides located exclusively in hypothalamic neurons that have extensive projections throughout the central nervous system and bind two different G protein-coupled receptors (OX1R and OX2R). Since its discovery in 1998, the orexin system has gained the interest of the scientific community as a potential therapeutic target for the treatment of different pathological conditions. Considering previous basic science research, a dual orexin receptor antagonist, suvorexant, was the first orexin agent to be approved by the US Food and Drug Administration to treat insomnia. In this review, we discuss and update the main preclinical and human studies involving the orexin system with several psychiatric and neurodegenerative diseases. This system constitutes a nice example of how basic scientific research driven by curiosity can be the best route to the generation of new and powerful pharmacological treatments.

From awareness to action: an urgent call to reduce mortality and improve outcomes in eating disorders.

High mortality rates and poor outcomes from eating disorders, especially anorexia nervosa, are largely preventable and require urgent action. A national strategy to address this should include prevention; early detection; timely access to integrated physical and psychological treatments; safe management of emergencies; suicide prevention; and investment in training, services and research.

Not niche: eating disorders as an example in the dangers of overspecialisation.

Labelling specific psychiatric concerns as 'niche' topics relegated to specialty journals obstructs high-quality research and clinical care for these issues. Despite their severity, eating disorders are under-represented in high-impact journals, underfunded, and under-addressed in psychiatric training. We provide recommendations to stimulate broad knowledge dissemination for under-acknowledged, yet severe, psychiatric disorders.

Shared genetic influences between eating disorders and gastrointestinal disease in a large, population-based sample of adult women and men.

BACKGROUND: Some preliminary research suggests higher rates of gastrointestinal disease in individuals with eating disorders (EDs). However, research is limited, and it remains unknown what etiologic factors account for observed associations. This was the first study to examine how EDs and dimensional ED symptoms (e.g. body dissatisfaction, binge eating) are phenotypically and etiologically associated with gastrointestinal disease in a large, population-based twin sample. METHODS: Adult female (N = 2980) and male (N = 2903) twins from the Michigan State University Twin Registry reported whether they had a lifetime ED (anorexia nervosa, bulimia nervosa, or binge-eating disorder) and completed a measure of dimensional ED symptoms. We coded the presence/absence of lifetime gastrointestinal disease (e.g. inflammatory bowel disease) based on responses to questions regarding chronic illnesses and medications. We first examined whether twins with gastrointestinal disease had higher rates of EDs and ED symptoms, then used correlated factors twin models to investigate genetic and environmental contributions to the overlap between disorders. RESULTS: Twins with gastrointestinal disease had significantly greater dimensional ED symptoms (ß = 0.21, p < 0.001) and odds of a lifetime ED (OR 2.90, p = 0.001), regardless of sex. Shared genetic factors fully accounted for the overlap between disorders, with no significant sex differences in etiologic associations. CONCLUSIONS: Comorbidity between EDs and gastrointestinal disease may be explained by overlap in genetic influences, potentially including inflammatory genes implicated in both types of disorders. Screening for gastrointestinal disease in people with EDs, and EDs in those with gastrointestinal disease, is warranted.

Using machine learning with passive wearable sensors to pilot the detection of eating disorder behaviors in everyday life.

BACKGROUND: Eating disorders (ED) are serious psychiatric disorders, taking a life every 52 minutes, with high relapse. There are currently no support or effective intervention therapeutics for individuals with an ED in their everyday life. The aim of this study is to build idiographic machine learning (ML) models to evaluate the performance of physiological recordings to detect individual ED behaviors in naturalistic settings. METHODS: From an ongoing study (Final N = 120), we piloted the ability for ML to detect an individual's ED behavioral episodes (e.g. purging) from physiological data in six individuals diagnosed with an ED, all of whom endorsed purging. Participants wore an ambulatory monitor for 30 days and tapped a button to denote ED behavioral episodes. We built idiographic (N = 1) logistic regression classifiers (LRC) ML trained models to identify onset of episodes (~600 windows) v. baseline (~571 windows) physiology (Heart Rate, Electrodermal Activity, and Temperature). RESULTS: Using physiological data, ML LRC accurately classified on average 91% of cases, with 92% specificity and 90% sensitivity. CONCLUSIONS: This evidence suggests the ability to build idiographic ML models that detect ED behaviors from physiological indices within everyday life with a high level of accuracy. The novel use of ML with wearable sensors to detect physiological patterns of ED behavior pre-onset can lead to just-in-time clinical interventions to disrupt problematic behaviors and promote ED recovery.

Change in food choice during acute treatment and the effect on longer-term outcome in patients with anorexia nervosa.

BACKGROUND: Restriction of food intake is a central pathological feature of anorexia nervosa (AN). Maladaptive eating behavior and, specifically, limited intake of calorie-dense foods are resistant to change and contribute to poor long-term outcomes. This study is a preliminary examination of whether change in food choices during inpatient treatment is related to longer-term clinical course. METHODS: Individuals with AN completed a computerized Food Choice Task at the beginning and end of inpatient treatment to determine changes in high-fat and self-controlled food choices. Linear regression and longitudinal analyses tested whether change in task behavior predicted short-term outcome (body mass index [BMI] at discharge) and longer-term outcome (BMI and eating disorder psychopathology). RESULTS: Among 88 patients with AN, BMI improved significantly with hospital treatment (p < 0.001), but Food Choice Task outcomes did not change significantly. Change in high-fat and self-controlled choices was not associated with BMI at discharge (r = 0.13, p = 0.22 and r = 0.10, p = 0.39, respectively). An increase in the proportion of high-fat foods selected (ß = 0.91, p = 0.02) and a decrease in the use of self-control (ß = -1.50, p = 0.001) predicted less decline in BMI over 3 years after discharge. CONCLUSIONS: Short-term treatment is associated with improvement in BMI but with no significant change, on average, in choices made in a task known to predict actual eating. However, the degree to which individuals increased high-fat choices during treatment and decreased the use of self-control over food choice were associated with reduced weight loss over the following 3 years, underscoring the need to focus on changing eating behavior in treatment of AN.

Investigating change in network structure of eating disorder symptoms after delivery of a smartphone app-based intervention.

BACKGROUND: Eating disorder (ED) research has embraced a network perspective of psychopathology, which proposes that psychiatric disorders can be conceptualized as a complex system of interacting symptoms. However, existing intervention studies using the network perspective have failed to find that symptom reductions coincide with reductions in strength of associations among these symptoms. We propose that this may reflect failure of alignment between network theory and study design and analysis. We offer hypotheses for specific symptom associations expected to be disrupted by an app-based intervention, and test sensitivity of a range of statistical metrics for identifying this intervention-induced disruption. METHODS: Data were analyzed from individuals with recurrent binge eating who participated in a randomized controlled trial of a cognitive-behavioral smartphone application. Participants were categorized into one of three groups: waitlist (n = 155), intervention responder (n = 49), and intervention non-responder (n = 77). Several statistical tests (bivariate associations, network-derived strength statistics, network invariance tests) were compared in ability to identify change in network structure. RESULTS: Hypothesized disruption to specific symptom associations was observed through change in bivariate correlations from baseline to post-intervention among the responder group but were not evident from symptom and whole-of-network based network analysis statistics. Effects were masked when the intervention group was assessed together, ignoring heterogeneity in treatment responsiveness. CONCLUSION: Findings are consistent with our contention that study design and analytic approach influence the ability to test network theory predictions with fidelity. We conclude by offering key recommendations for future network theory-driven interventional studies.

Lisdexamfetamine maintenance treatment for binge-eating disorder following successful treatments: randomized double-blind placebo-controlled trial.

BACKGROUND: Controlled research examining maintenance treatments for responders to acute interventions for binge-eating disorder (BED) is limited. This study tested efficacy of lisdexamfetamine (LDX) maintenance treatment amongst acute responders. METHODS: This prospective randomized double-blind placebo-controlled single-site trial, conducted March 2019 to September 2023, tested LDX as maintenance treatment for responders to acute treatments with LDX-alone or with cognitive-behavioral therapy (CBT + LDX) for BED with obesity. Sixty-one (83.6% women, mean age 44.3, mean BMI 36.1 kg/m2) acute responders were randomized to LDX (N = 32) or placebo (N = 29) for 12 weeks; 95.1% completed posttreatment assessments. Mixed-models and generalized-estimating equations comparing maintenance LDX v. placebo included main/interactive effects of acute (LDX or CBT + LDX) treatments to examine their predictive/moderating effects. RESULTS: Relapse rates (to diagnosis-level binge-eating frequency) following maintenance treatments were 10.0% (N = 3/30) for LDX and 17.9% (N = 5/28) for placebo; intention-to-treat binge-eating remission rates were 59.4% (N = 19/32) and 65.5% (N = 19/29), respectively. Maintenance LDX and placebo did not differ significantly in binge-eating but differed in weight-loss and eating-disorder psychopathology. Maintenance LDX was associated with significant weight-loss (-2.3%) whereas placebo had significant weight-gain (+2.2%); LDX and placebo differed significantly in weight-change throughout treatment and at posttreatment. Eating-disorder psychopathology remained unchanged with LDX but increased significantly with placebo. Acute treatments did not significantly predict/moderate maintenance-treatment outcomes. CONCLUSIONS: Adults with BED/obesity who respond to acute lisdexamfetamine treatment (regardless of additionally receiving CBT) had good maintenance during subsequent 12-weeks. Maintenance lisdexamfetamine, relative to placebo, did not provide further benefit for binge-eating but was associated with significantly better eating-disorder psychopathology outcomes and greater weight-loss.

The natural course of binge-eating disorder: findings from a prospective, community-based study of adults.

BACKGROUND: Epidemiological data offer conflicting views of the natural course of binge-eating disorder (BED), with large retrospective studies suggesting a protracted course and small prospective studies suggesting a briefer duration. We thus examined changes in BED diagnostic status in a prospective, community-based study that was larger and more representative with respect to sex, age of onset, and body mass index (BMI) than prior multi-year prospective studies. METHODS: Probands and relatives with current DSM-IV BED (n = 156) from a family study of BED ('baseline') were selected for follow-up at 2.5 and 5 years. Probands were required to have BMI > 25 (women) or >27 (men). Diagnostic interviews and questionnaires were administered at all timepoints. RESULTS: Of participants with follow-up data (n = 137), 78.1% were female, and 11.7% and 88.3% reported identifying as Black and White, respectively. At baseline, their mean age was 47.2 years, and mean BMI was 36.1. At 2.5 (and 5) years, 61.3% (45.7%), 23.4% (32.6%), and 15.3% (21.7%) of assessed participants exhibited full, sub-threshold, and no BED, respectively. No participants displayed anorexia or bulimia nervosa at follow-up timepoints. Median time to remission (i.e. no BED) exceeded 60 months, and median time to relapse (i.e. sub-threshold or full BED) after remission was 30 months. Two classes of machine learning methods did not consistently outperform random guessing at predicting time to remission from baseline demographic and clinical variables. CONCLUSIONS: Among community-based adults with higher BMI, BED improves with time, but full remission often takes many years, and relapse is common.

Socioeconomic inequity in the utilization of healthcare among people with eating disorders in Australia.

BACKGROUND: Little is known about socioeconomic equity in access to healthcare among people with eating disorders in Australia. This study aims to measure the extent of inequity in eating disorder-related healthcare utilization, analyze trends, and explore the sources of inequalities using New South Wales (NSW) administrative linked health data for 2005 to 2020. METHODS: Socioeconomic inequities were measured using concentration index approach, and decomposition analysis was conducted to explain the factors accounting for inequality. Healthcare utilization included: public inpatient admissions, private inpatient admissions, visits to public mental health outpatient clinics and emergency department visits, with three different measures (probability of visit, total and conditional number of visits) for each outcome. RESULTS: Private hospital admissions due to eating disorders were concentrated among individuals from higher socioeconomic status (SES) from 2005 to 2020. There was no significant inequity in the probability of public hospital admissions for the same period. Public outpatient visits were utilized more by people from lower SES from 2008 to 2020. Emergency department visits were equitable, but more utilized by those from lower SES in 2020. CONCLUSIONS: Public hospital and emergency department services were equitably used by people with eating disorders in NSW, but individuals from high SES were more likely to be admitted to private hospitals for eating disorder care. Use of public hospital outpatient services was higher for those from lower SES. These findings can assist policymakers in understanding the equity of the healthcare system and developing programs to improve fairness in eating disorder-related healthcare in NSW.

Mechanisms underlying the development of eating disorders and disordered eating in adolescent females with type 1 diabetes.

OBJECTIVE: People with Type 1 diabetes (T1D) face an increased risk of eating disorders/disordered eating (ED/DE), with adolescents being particularly vulnerable. Empirical knowledge on the mechanisms underlying development of ED/DE in T1D is crucial for evolving prevention strategies. RESEARCH DESIGN AND METHODS: Fourteen semi-structured interviews with adolescent females with T1D and ED/DE between 14 and 18 years were conducted and analyzed using reflexive thematic analysis. RESULTS: Analyses identified four main themes; 'Interconnected afflictions', 'Judgment', 'Feeling Different', and 'Chaos & Control', These themes explore the interconnectedness of T1D and ED/DE, with shame and guilt emerging as common underlying mechanism. The development of a biopsychosocial model was based on the integration of these data with existing models. CONCLUSIONS: The study extends previous developmental pathways of ED/DE in adolescents with T1D. We propose a biopsychosocial model that incorporates various factors: predisposing factors such as parental management of T1D and weight gain during adolescence; precipitating factors including comments on weight, frequency of weighing, perceptions of surveillance; the perpetuating bilateral influence of ED/DE and T1D and finally highlighting the protective mechanisms of disease acceptance encompassing parental handling of diagnosis and the contribution of healthcare professionals (HCP's) role in psychoeducation. The present study highlight the vulnerability of adolescence in the presence of T1D, particularly concerning issues related to eating, weight, and body. It offers clinically relevant insights, with the aim to improve communication and management strategies for this very specific group.

Profiles of disordered eating behaviour in type 1 diabetes using the DEPS-R and behaviour and glycaemic outcomes in a real-life setting.

AIMS: The Diabetes Eating Problems Survey - Revised (DEPS-R) is commonly used to assess disordered eating behaviour (DEB) in individuals with type 1 diabetes and has advantages compared to other measures not specifically tailored to diabetes. A score ≥20 on the DEPS-R is used to indicate clinically significant DEB; however, it does not distinguish between eating disorder (ED) phenotypes necessary to guide treatment decisions, limiting clinical utility. METHODS: The current study used latent class analysis to identify distinct person-centred profiles of DEB in adults with type 1 diabetes using the DEPS-R. Analysis of Variance with Games Howell post-hoc comparisons was then conducted to examine the correspondence between the profiles and binge eating, insulin restriction and glycaemic control (HbA1c, mean blood glucose, and percent time spent in hyperglycaemia) during 3 days of assessment in a real-life setting. RESULTS: Latent class analysis indicated a 4-class solution, with patterns of item endorsement suggesting the following profiles: Bulimia, Binge Eating, Overeating and Low Pathology. Differences in binge eating, insulin restriction and glycaemic control were observed between profiles during 3 days of at-home assessment. The Bulimia profile was associated with highest HbA1c and 3-day mean blood glucose. CONCLUSIONS: There are common patterns of responses on the DEPS-R that appear to reflect different ED phenotypes. Profiles based on the DEPS-R corresponded with behaviour in the real-life setting as expected and were associated with different glycaemic outcomes. Results may have implications for the use of the DEPS-R in research and clinical settings.

A cognitive behavioural model of the bidirectional relationship between disordered eating and diabetes self care in adult men with Type 1 diabetes mellitus.

AIMS: This qualitative study aimed to develop the first cognitive behavioural (CBT) model outlining the development and maintenance of disordered eating in adult men living with Type 1 diabetes to improve on previous theoretical models of Type 1 diabetes and disordered eating and to draw comparisons to women with Type 1 diabetes and disordered eating. METHODS: Twenty-seven men (n = 16 with Type 1 diabetes and disordered eating, n = 11 with Type 1 diabetes without disordered eating) participated in semi-structured interviews. Data were analysed using thematic analysis and individual CBT formulations were developed for each participant to inform the model. RESULTS: Men with Type 1 diabetes and disordered eating experience negative thoughts about food, insulin, weight/shape and diabetes itself, which cause negative emotions such as fear and vulnerability and difficulties with diabetes self care such as problems with hyper and hypoglycaemia and problems accessing structured education and technology result in men feeling more dissatisfied about their body weight/shape. CONCLUSIONS: This CBT model of disordered eating in men with Type 1 diabetes can guide new interventions.

Current perspectives on brain circuits involved in food addiction-like behaviors.

There is an emerging view that the increased availability of energy-dense foods in our society is contributing to excessive food consumption which could lead to food addiction-like behavior. Particularly, compulsive eating patterns are predominant in people suffering from eating disorders (binge-eating disorder, bulimia and anorexia nervosa) and obesity. Phenotypically, the behavioral pattern exhibits a close resemblance to individuals suffering from other forms of addiction (drug, sex, gambling). Growing body of evidence in neuroscience research is showing that excessive consumption of energy-dense foods alters the brain circuits implicated in reward, decision-making, control, habit formation, and emotions that are central to drug addiction. Here, we review the current understanding of the circuits of food addiction-like behaviors and highlight the future possibility of exploring those circuits to combat obesity and eating disorders.

Long-Term Dynamics of Serum α-MSH and α-MSH-Binding Immunoglobulins with a Link to Gut Microbiota Composition in Patients with Anorexia Nervosa.

INTRODUCTION: Immunoglobulins (Ig) reactive with α-melanocyte-stimulating hormone (α-MSH), an anorexigenic neuropeptide, are present in humans and were previously associated with eating disorders. In this longitudinal study involving patients with anorexia nervosa (AN), we determined whether α-MSH in serum is bound to IgG and analyzed long-term dynamics of both α-MSH peptide and α-MSH-reactive Ig in relation to changes in BMI and gut microbiota composition. METHODS: The study included 64 adolescents with a restrictive form of AN, whose serum samples were collected at hospital admission, discharge, and during a 1-year follow-up visit and 41 healthy controls, all females. RESULTS: We found that in both study groups, approximately 40% of serum α-MSH was reversibly bound to IgG and that levels of α-MSH-reactive IgG but not of α-MSH peptide in patients with AN were low at hospital admission but recovered 1 year later. Total IgG levels were also low at admission. Moreover, BMI-standard deviation score correlated positively with α-MSH IgG in both groups studied but negatively with α-MSH peptide only in controls. Significant correlations between the abundance of specific bacterial taxa in the gut microbiota and α-MSH peptide and IgG levels were found in both study groups, but they were more frequent in controls. CONCLUSION: We conclude that IgG in the blood plays a role as an α-MSH-binding protein, whose characteristics are associated with BMI in both patients with AN and controls. Furthermore, the study suggests that low production of α-MSH-reactive IgG during the starvation phase in patients with AN may be related to altered gut microbiota composition.

Daily Relationship Functioning and Disordered Eating Behaviors Among Sexual Minority Women in Same-Sex Relationships.

BACKGROUND AND PURPOSE: The present study aimed to examine associations between different types of relationship functioning and disordered eating behaviors (DEBs) in the everyday lives of sexual minority women in same-sex relationships-an at-risk population that has not been assessed in this context. METHODS: Participants included 321 young sexual minority women (Mage = 27.56, SD = 3.67) in same-sex relationships who completed surveys assessing their daily relationship functioning and DEB use each day for a 14-day daily diary period. Multilevel structural equation modeling was used to examine daily-, person-, and couple-level associations among women's daily relationship functioning (general relationship functioning, positive and negative relational behaviors they and, separately, their partners engaged in) and DEBs (overeating, loss of control eating, emotional eating, and dietary restriction). RESULTS: Results generally indicated that more positive and less negative daily relationship functioning across all assessed constructs was associated with less same-day emotional eating. In contrast, associations between all daily relationship functioning constructs and loss of control eating were not significant, nor were any relationship functioning-DEB associations at the couple level. More circumscribed patterns of association were identified for associations between the relationship functioning constructs, and overeating and dietary restriction. CONCLUSIONS: Collectively, these findings provide insight into how aspects of daily relationship functioning map onto sexual minority women's daily engagement in DEBs that are linked to poor health long-term, and directions for future research and clinical practice that may warrant consideration moving forward to help advance the evidence-base and care for this historically overlooked and underserved population.

The present study examined associations between different types of relationship functioning (e.g., general relationship functioning, positive and negative relational behaviors that participants and their partners engaged in during their interactions with one another) and disordered eating behaviors (DEBs) in the everyday lives of sexual minority women in same-sex relationships. Results generally indicated that on days when women reported more positive and less negative daily relationship functioning, they also reported less emotional eating that day. In contrast, associations between different types of daily relationship functioning and loss of control eating were not significant. Furthermore, associations between different types of daily relationship functioning relative to overeating and dietary restriction varied based on the type of relationship functioning and DEB under consideration. Collectively, these findings provide insight into how different types of daily relationship functioning map onto sexual minority women's daily engagement in DEBs that are linked to poor health long-term. These findings also provide directions for future research and clinical practice that may warrant consideration moving forward to help advance the evidence base and care for this historically overlooked and underserved population.

Altered learning from positive feedback in adolescents with anorexia nervosa.

OBJECTIVE: Anorexia nervosa (AN) is characterized by severe restriction of calorie intake, which persists despite serious medical and psychological sequelae of starvation. Several prior studies have identified impaired feedback learning among individuals with AN, but whether it reflects a disturbance in learning from positive feedback (i.e., reward), negative feedback (i.e., punishment), or both, and the extent to which this impairment is related to severity and duration of illness, has not been clarified. METHOD: Participants were female adolescents with AN (n = 76) and healthy teen volunteers (HC; n = 38) between the ages of 12-18 years who completed a probabilistic reinforcement learning task. A Bayesian reinforcement learning model was used to calculate separate learning rates for positive and negative feedback. Exploratory analyses examined associations between feedback learning and duration of illness, eating disorder severity, and self/parent reports of reward and punishment sensitivity. RESULTS: Adolescents with AN had a significantly lower rate of learning from positive feedback relative to HC. Patients and HC did not differ in learning from negative feedback or on overall task performance measures. Feedback learning parameters were not significantly associated with duration of illness, eating disorder severity, or questionnaire-based reports of reward and punishment sensitivity. CONCLUSION: Adolescents with AN showed a circumscribed deficit in learning from reward that was not associated with duration of illness or reported sensitivity to reward or punishment. Subsequent longitudinal research should explore whether differences in learning from positive feedback relate to course of illness in youth with AN.