Reward responsivity and habit formation in the co-occurrence of restrictive eating and nonsuicidal self-injury.

Dysfunctions in reward and/or habit formation have been proposed as factors contributing individually to the maintenance of restrictive eating and nonsuicidal self-injury (NSSI). However, despite the high comorbidity between these behaviors, the associations between reward and habit formation in their co-occurrence remains unclear. This study examined self-reported reward responsivity and habit strength among individuals with co-occurring restrictive eating and NSSI (Comorbid group; n = 108) and those with one behavior only (One-behavior group; n = 113). Hierarchical logistic regression analyses assessed the association between reward and habit features and the co-occurrence of restrictive eating and NSSI, accounting for the effects of impulsivity (a characteristic commonly considered to underlie co-occurring disordered eating and NSSI). Partial correlations examined the relationships between these features and the severity of eating disorder and NSSI symptoms, also controlling for impulsivity. Lower reward responsivity was associated with the co-occurrence of restrictive eating and NSSI, even after accounting for impulsivity (p = 0.017). In exploratory analyses, this relationship was no longer significant after accounting for self-reported depression. No significant associations were found regarding habit formation and restrictive eating and NSSI co-occurrence. Lower reward responsivity was linked to increased NSSI frequency and versatility in both groups and associated with severity of eating pathology in the Comorbid group (ps < 0.05). Our findings suggest that blunted reward responsivity may relate to the co-occurrence of restrictive eating, NSSI, and depressive symptoms, as well as the severity of restrictive eating and NSSI. Reward disturbances may serve as a crucial target in the treatment of multiple self-destructive behaviors.

Naturalistic symptom trajectories of atypical anorexia nervosa, anorexia nervosa, and bulimia nervosa in a prospective cohort study of United States college students.

OBJECTIVE: Research on the natural course of symptoms of atypical anorexia nervosa (AN) relative to AN and bulimia nervosa (BN) is limited yet needed to inform nosology and improve understanding of atypical AN. This study aimed to 1) characterize trajectories of eating disorder and internalizing (anxiety, depression) symptoms in college students with and without a history of atypical AN, AN, and BN; and 2) compare sex and race/ethnicity distributions across groups. METHOD: United States college students who participated in Spit for Science™, a prospective cohort study, were classified as having a history of atypical AN (n = 125), AN (n = 160), BN (n = 617), or as non-eating-disorder controls (NCs, n = 5876). Generalized and linear mixed-effects models assessed group differences in eating and internalizing symptom trajectories, and logistic regression compared groups on sex and race/ethnicity distributions. RESULTS: Atypical AN participants demonstrated elevated eating disorder and internalizing symptoms compared to NCs during college, but less severe symptoms than AN and BN participants. Although all eating disorder groups showed signs of improvement in fasting and driven exercise, purging and depression remained elevated. Atypical AN participants showed increasing anxiety and stable binge-eating trajectories compared to AN and/or BN participants. The atypical AN group comprised significantly more people of color than the AN group. DISCUSSION: Findings underscore that atypical AN is a severe psychiatric disorder. As atypical AN may present as less severe than AN and BN and disproportionately affects people of color, clinicians should be mindful of biases that could delay diagnosis and care. PUBLIC SIGNIFICANCE: College students with histories of atypical AN, AN, and BN demonstrated improvements in fasting and driven exercise and stable purging and depression levels. Atypical AN students showed worsening anxiety and stable binge-eating trajectories compared to favorable changes among AN and BN students. A higher percentage of atypical AN (vs. AN) students were people of color. Findings may improve the detection of atypical AN in college students.

The explore/exploit trade-off: An ecologically valid and translational framework that can advance mechanistic understanding of eating disorders.

The explore/exploit trade-off is a decision-making process that is conserved across species and balances exploring unfamiliar choices of unknown value with choosing familiar options of known value to maximize reward. This framework is rooted in behavioral ecology and has traditionally been used to study maladaptive versus adaptive non-human animal foraging behavior. Researchers have begun to recognize the potential utility of understanding human decision-making and psychopathology through the explore/exploit trade-off. In this article, we propose that explore/exploit trade-off holds promise for advancing our mechanistic understanding of decision-making processes that confer vulnerability for and maintain eating pathology due to its neurodevelopmental bases, conservation across species, and ability to be mathematically modeled. We present a model for how suboptimal explore/exploit decision-making can promote disordered eating and present recommendations for future research applying this framework to eating pathology. Taken together, the explore/exploit trade-off provides a translational framework for expanding etiologic and maintenance models of eating pathology, given developmental changes in explore/exploit decision-making that coincide in time with the emergence of eating pathology and evidence of biased explore/exploit decision-making in psychopathology. Additionally, understanding explore/exploit decision-making in eating disorders may improve knowledge of their underlying pathophysiology, informing targeted clinical interventions such as neuromodulation and pharmacotherapy. PUBLIC SIGNIFICANCE STATEMENT: The explore/exploit trade-off is a cross-species decision-making process whereby organisms choose between a known option with a known reward or sampling unfamiliar options. We hypothesize that imbalanced explore/exploit decision-making can promote disordered eating and present preliminary data. We propose that explore/exploit trade-off has significant potential to advance understanding of the neurocognitive and neurodevelopmental mechanisms of eating pathology, which could ultimately guide revisions of etiologic models and inform novel interventions.

El balance entre explorar y explotar es un proceso de toma de decisiones que se conserva a través de las especies y equilibra la exploración de opciones desconocidas de valor desconocido con la elección de opciones familiares de valor conocido para maximizar la recompensa. Este marco está arraigado en la ecología del comportamiento y tradicionalmente se ha utilizado para estudiar el comportamiento de forrajeo no adaptativo versus adaptativo en animales no humanos. Los investigadores han comenzado a reconocer la utilidad potencial de entender la toma de decisiones humanas y la psicopatología a través del balance entre explorar y explotar. En este artículo, proponemos que el balance entre explorar y explotar ofrece promesas para avanzar en nuestra comprensión mecanicista de los procesos de toma de decisiones que confieren vulnerabilidad y mantienen la patología alimentaria debido a sus bases neurodesarrolladoras, su conservación a través de las especies y su capacidad de ser modelado matemáticamente. Presentamos un modelo de cómo la toma de decisiones subóptima entre explorar y explotar puede promover la alimentación disfuncional y presentamos recomendaciones para futuras investigaciones que apliquen este marco a la patología alimentaria. En conjunto, el balance entre explorar y explotar proporciona un marco translacional para expandir los modelos etiológicos y de mantenimiento de la patología alimentaria, dadas los cambios en el desarrollo de la toma de decisiones entre explorar y explotar que coinciden en el tiempo con la aparición de la patología alimentaria y la evidencia de una toma de decisiones entre explorar y explotar sesgada en la psicopatología. Además, comprender la toma de decisiones entre explorar y explotar en los trastornos alimentarios puede mejorar el conocimiento de su fisiopatología subyacente, informando intervenciones clínicas dirigidas como la neuromodulación y la farmacoterapia.

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.

A randomized, controlled pilot study of positive affect treatment adapted for anorexia nervosa.

OBJECTIVE: Novel treatments for adults with anorexia nervosa (AN) are sorely needed. Although psychological interventions have been developed for AN, none have been identified as superior to one another or nonspecific treatments. Common comorbidities (e.g., mood and anxiety disorders) are rarely targeted in AN treatments, possibly impairing long-term clinical improvement. AN is associated with reward processing dysfunctions paralleling those identified in affective disorders; however, few treatments directly target these processes. METHOD: We adapted Positive Affect Treatment, a neuroscience-informed behavioral treatment developed for affective disorders, to the treatment of AN (PAT-AN). Adults with AN (N = 20) were randomized to 20 weeks of PAT-AN or waitlist to investigate the feasibility, acceptability, preliminary efficacy, and target engagement (on reward mechanisms) of PAT-AN. RESULTS: PAT-AN demonstrated strong retention (100%) and acceptability ratings (M = 5.67-5.95 on a 7-point scale). BMI (p = .006) and eating disorder symptoms (p < .001) improved over PAT-AN sessions. The PAT-AN group showed medium to large pre-to-post-treatment improvements in BMI, eating disorder symptoms and impairment, depressive and anxiety symptoms, and some reward indices (ds = .56-.87); changes were largely sustained at 3-month follow-up. Waitlist showed negligible changes (ds < .20) on nearly all measures. DISCUSSION: PAT-AN holds promise as an innovative treatment with capability to simultaneously improve eating disorder symptoms, affective symptoms, and underlying reward mechanisms. Findings should be interpreted cautiously due to small sample size and permitted concurrent enrollment in other treatments. Future, larger-scale research is warranted to establish the efficacy of PAT-AN. PUBLIC SIGNIFICANCE: This study provided a preliminary evaluation of Positive Affect Treatment for anorexia nervosa (PAT-AN), a novel, neuroscience-informed treatment aimed at increasing rewarding life experiences outside of one's eating disorder. Initial results suggest that PAT-AN is considered acceptable and may alleviate eating disorder, depressive, and anxiety symptoms. Therefore, this study presents promising data on a treatment that may hold potential for improving the lives of individuals with this disorder.

Learned industriousness as a translational mechanism in anorexia nervosa.

It remains unexplained why some behaviours persist despite being non-hedonic and ostensibly aversive. This phenomenon is especially baffling when such behaviours are taken to excess in the form of psychopathology. Anorexia nervosa is one psychiatric disorder in which effortful behaviours that most people find unpleasant (suchas restrictive eating) are persistently performed. We propose thatthe social psychology theory of learned industriousness providesa novel mechanistic account for such phenomena. This theoryposits that high-effort behaviour can be conditioned to acquire secondary reinforcing properties through repeated pairing with reward. Accordingly, effort sensations become less aversive andmore appetitive, increasing willingness to engage in effortful behaviour. In this Perspective, we review pre-clinical behaviouraland biological data that support learned industriousness, contrast learned industriousness with other models of non-hedonic persistence (such as habit learning), highlight evidence that supports learned industriousness in individuals with anorexia nervosa and consider implications of the model, including translation to other psychiatric presentations.

Development of transdiagnostic clinical risk prediction models for 12-month onset and course of eating disorders among adolescents in the community.

OBJECTIVE: To develop and internally validate risk prediction models for adolescent onset and persistence of eating disorders. METHODS: N = 963 Australian adolescents (11-19 years) in the EveryBODY Study cohort completed online surveys in 2018 and 2019. Models were built to predict 12-month risk of (1) onset, and (2) persistence of a DSM-5 eating disorder. RESULTS: Onset Model. Of the n = 687 adolescents without an eating disorder at baseline, 16.9% were identified with an eating disorder after 12 months. The prediction model was based on evidence-based risk factors for eating disorder onset available within the dataset (sex, body mass index percentile, strict weight loss dieting, history of bullying, psychological distress, weight/shape concerns). This model showed fair discriminative performance (mean AUC = .75). The most important factors were psychological distress, weight and shape concerns, and female sex. Diagnostic Persistence Model. Of the n = 276 adolescents with an eating disorder at baseline, 74.6% were identified as continuing to meet criteria for an eating disorder after 12 months. The prediction model for diagnostic persistence was based on available evidence-based risk factors for eating disorder persistence (purging, distress, social impairment). This model showed poor discriminative performance (mean AUC = .65). The most important factors were psychological distress and self-induced vomiting for weight control. DISCUSSION: We found preliminary evidence for the utility of a parsimonious model for 12-month onset of an eating disorder among adolescents in the community. Future research should include additional evidence-based risk factors and validate models beyond the original sample. PUBLIC SIGNIFICANCE: This study demonstrated the feasibility of developing parsimonious and accurate models for the prediction of future onset of an eating disorder among adolescents. The most important predictors in this model included psychological distress and weight and shape concerns. This study has laid the ground work for future research to build and test more accurate prediction models in diverse samples, prior to translation into a clinical tool for use in real world settings to aid decisions about referral to early intervention.

Difficulties with positive emotion regulation in anorexia nervosa.

Individuals with anorexia nervosa (AN) have well-documented difficulties regulating negative emotions, but less is known about positive emotion regulation in this population. To address this gap, we compared responses on the Difficulties in Emotion Regulation Scale-Positive questionnaire and the traditional DERS questionnaire (measuring negative affect dysregulation) between females with AN (n = 30) and demographically-matched controls without an eating disorder history (NC; n = 30) and examined relations between positive emotion regulation and clinical symptoms. Results indicated that individuals with AN demonstrated greater difficulty regulating negative (p < 0.001, d = 2.75) and positive (p < 0.001, d = 1.08) emotions compared to NC participants. Specifically, the AN group reported heightened positive emotion nonacceptance (p = 0.004, d = 0.78) and impulsivity (p = 0.003, d = 0.81). Greater positive emotion nonacceptance was associated with higher anxiety (p = 0.015) and depression (p = 0.022) among individuals with AN. Unexpectedly, more positive emotion impulsivity was associated with less restrictive eating in AN (p < 0.001). Findings were largely maintained even after controlling for negative emotion dysregulation and psychotropic medication use. The results suggest that reducing shame related to positive emotions could improve mood in AN; alternatively, relinquishing control when experiencing positive emotion could reduce restriction. More research is warranted on positive emotion regulation as a treatment target for AN.

Is the effect of menu energy labelling on consumer behaviour equitable? A pooled analysis of twelve randomized control experiments.

Menu energy labelling has been implemented as a public health policy to promote healthier dietary choices and reduce obesity. However, it is unclear whether the influence energy labelling has on consumer behaviour differs based on individuals' demographics or characteristics and may therefore produce inequalities in diet. Data were analysed from 12 randomized control trials (N = 8508) evaluating the effect of food and drink energy labelling (vs. labelling absent) on total energy content of food and drink selections (predominantly hypothetical) in European and US adults. Analyses examined the moderating effects of participant age, sex, ethnicity/race, education, household income, body mass index, dieting status, food choice motives and current hunger on total energy content of selections. Energy labelling was associated with a small reduction (f2 = 0.004, -50 kcal, p < 0.001) in total energy selected compared to the absence of energy labelling. Participants who were female, younger, white, university educated, of a higher income status, dieting, motivated by health and weight control when making food choices, and less hungry, tended to select menu items of lower energy content. However, there was no evidence that the effect of energy labelling on the amount of energy selected was moderated by any of the participants' demographics or characteristics. Energy labelling was associated with a small reduction in energy content of food selections and this effect was similar across a range of participants' demographics and characteristics. These preliminary findings suggest that energy labelling policies may not widen existing inequalities in diet.

Utility of Downstream Biomarkers to Assess and Optimize Intranasal Delivery of Oxytocin.

Oxytocin (OT), a mammalian neurohormone associated with social cognition and behavior, can be administered in its synthetic form intranasally (IN) and impact brain chemistry and behavior. IN-OT shows potential as a noninvasive intervention for disorders characterized by social challenges, e.g., autism spectrum disorder (ASD) and anorexia nervosa (AN). To evaluate IN-OT's efficacy, we must quantify OT uptake, availability, and clearance; thus, we assessed OT levels in urine (uOT) before and after participants (26 ASD, 7 AN, and 7 healthy controls) received 40 IU IN-OT or placebo across two sessions using double-blind, placebo-controlled crossover designs. We also measured uOT and plasma (pOT) levels in a subset of participants to compare the two sampling methods. We found significantly higher uOT and pOT following intranasal delivery of active compound versus placebo, but analyses yielded larger effect sizes and more clearly differentiated pre-post-OT levels for uOT than pOT. Further, we applied a two-step cluster (TSC), blinded backward-chaining approach to determine whether active/placebo groups could be identified by uOT and pOT change alone; uOT levels may serve as an accessible and accurate systemic biomarker for OT dose-response. Future studies will explore whether uOT levels correlate directly with behavioral targets to improve dosing for therapeutic goals.

Biased and inflexible interpretations of ambiguous social situations: Associations with eating disorder symptoms and socioemotional functioning.

BACKGROUND: Research indicates that difficulties across multiple socioemotional functioning domains (e.g., social emotion expression/regulation, response to social elicitors of emotion) and negatively biased interpretations of ambiguous social situations may affect eating disorder symptoms. The impact of inflexible interpretations of social situations on eating disorder symptoms is less clear. The present study therefore examined relations between inflexible and biased social interpretations, socioemotional functioning, and eating disorder symptoms. METHOD: A total of 310 participants from the general population, recruited from an online crowdsourcing platform, completed measures of socioemotional functioning (e.g., rejection sensitivity, negative social exchange), eating disorder symptoms, and positive and negative interpretation bias and inflexibility on a single measurement occasion. RESULTS: Socioemotional functioning impairments (Pillai's trace = 0.11, p < .001), but not negative (ß = .07, p = .162) or positive (ß = -.01, p = .804) interpretation bias or inflexible interpretations (ß = .04, p = .446), were associated with eating disorder symptoms in multiple regression models. In network analyses controlling statistically for multiple markers of socioemotional functioning, eating disorder symptoms were directly associated with negative (but not positive) interpretation bias. Inflexible interpretations were indirectly linked to symptoms via co-dampening of positive emotions. Exploratory causal discovery analyses suggested that several socioemotional functioning variables (social anxiety, depression, negative social exchange) may cause eating disorder symptoms. CONCLUSIONS: Consistent with cognitive-interpersonal models of disordered eating, our results suggest that less accurate (biased, inflexible) interpretations of social information contribute to patterns of cognition (anxious anticipation of rejection) and emotion regulation (down-regulation of positive social emotion) thought to encourage disordered eating. PUBLIC SIGNIFICANCE: This study suggests that less accurate interpretations of ambiguous social information encourage anxious anticipation of rejection and downregulation of positive social emotions, both of which are thought to promote eating disorder symptoms. Knowledge provided by this study about the likely relations between interpretive processes, social/emotional functioning, and eating disorder symptoms may help inform treatments for eating disorders, particularly those that attempt to modify patterns of interpretation.

Beyond Description and Deficits: How Computational Psychiatry Can Enhance an Understanding of Decision-Making in Anorexia Nervosa.

PURPOSE OF REVIEW: Despite decades of research, knowledge of the mechanisms maintaining anorexia nervosa (AN) remains incomplete and clearly effective treatments elusive. Novel theoretical frameworks are needed to advance mechanistic and treatment research for this disorder. Here, we argue the utility of engaging a novel lens that differs from existing perspectives in psychiatry. Specifically, we argue the necessity of expanding beyond two historically common perspectives: (1) the descriptive perspective: the tendency to define mechanisms on the basis of surface characteristics and (2) the deficit perspective: the tendency to search for mechanisms associated with under-functioning of decision-making abilities and related circuity, rather than problems of over-functioning, in psychiatric disorders. RECENT FINDINGS: Computational psychiatry can provide a novel framework for understanding AN because this approach emphasizes the role of computational misalignments (rather than absolute deficits or excesses) between decision-making strategies and environmental demands as the key factors promoting psychiatric illnesses. Informed by this approach, we argue that AN can be understood as a disorder of excess goal pursuit, maintained by over-engagement, rather than disengagement, of executive functioning strategies and circuits. Emerging evidence suggests that this same computational imbalance may constitute an under-investigated phenotype presenting transdiagnostically across psychiatric disorders. A variety of computational models can be used to further elucidate excess goal pursuit in AN. Most traditional psychiatric treatments do not target excess goal pursuit or associated neurocognitive mechanisms. Thus, targeting at the level of computational dysfunction may provide a new avenue for enhancing treatment for AN and related disorders.

The role of rumination and positive beliefs about rumination in eating pathology.

PURPOSE: General and eating disorder (ED)-specific ruminations have been identified as key factors that may contribute to eating pathology. Positive beliefs about rumination (e.g., "Ruminating helps me to prevent future mistakes") may impact this association. However, the effect of positive beliefs about rumination on the links between rumination and ED symptom severity has not been investigated. This study sought to clarify relations between rumination and ED symptom severity and to evaluate the potential moderating effect of positive beliefs about rumination on these associations. METHODS: During a laboratory visit, undergraduate participants (N = 473, MAge = 18.90 ± 2.27, MBMI = 23.45 kg/m2 ± 4.31, 54.8% female) completed an online battery of questionnaires assessing general and ED-specific ruminative processes (e.g., brooding, reflection), positive beliefs about rumination, and global ED symptoms. Hierarchical multiple regression analyses assessed the unique contributions of specific ruminative processes, and the moderating effect of positive beliefs on associations between ruminative processes and ED symptom severity. RESULTS: Hierarchical multiple regression results suggest that, after controlling for gender and BMI, ED-specific brooding, b = 1.32, SE = 0.13, ß = 0.46, p < 0.0001, and reflection, b = 1.44, SE = 0.33, ß = 0.19, p < 0.0001, accounted for unique variance in ED symptom severity. Moderation model results indicate that, at low levels of general reflection, b = - 0.06, SE = 0.02, ß = - 0.51, p = 0.003, and ED-specific reflection, b = - 0.15, SE = 0.03, ß = - 0.59, p < 0.0001, increased positive beliefs about rumination were associated with greater ED symptom severity. CONCLUSION: Findings suggest ED-specific rumination accounts for ED symptom severity above and beyond general rumination, and that rumination-related expectancies influence the association between reflection and ED symptom severity. LEVEL OF EVIDENCE: Level III, evidence obtained from a well-designed cohort study.

Computational validity: using computation to translate behaviours across species.

We propose a new conceptual framework (computational validity) for translation across species and populations based on the computational similarity between the information processing underlying parallel tasks. Translating between species depends not on the superficial similarity of the tasks presented, but rather on the computational similarity of the strategies and mechanisms that underlie those behaviours. Computational validity goes beyond construct validity by directly addressing questions of information processing. Computational validity interacts with circuit validity as computation depends on circuits, but similar computations could be accomplished by different circuits. Because different individuals may use different computations to accomplish a given task, computational validity suggests that behaviour should be understood through the subject's point of view; thus, behaviour should be characterized on an individual level rather than a task level. Tasks can constrain the computational algorithms available to a subject and the observed subtleties of that behaviour can provide information about the computations used by each individual. Computational validity has especially high relevance for the study of psychiatric disorders, given the new views of psychiatry as identifying and mediating information processing dysfunctions that may show high inter-individual variability, as well as for animal models investigating aspects of human psychiatric disorders. This article is part of the theme issue 'Systems neuroscience through the lens of evolutionary theory'.

Functional assessment of restrictive eating: A three-study clinically heterogeneous and transdiagnostic investigation.

Restrictive eating is common and associated with negative psychological outcomes across the life span and eating disorder (ED) severity levels. Little is known about functional processes that maintain restriction, especially outside of narrow diagnostic categories (e.g., anorexia nervosa). Here, we extend research on operant four-function models (identifying automatic negative, automatic positive, social negative, and social positive reinforcement functions) that have previously been applied to nonsuicidal self-injury (NSSI), binge eating, and purging to restricting. We assessed restrictive eating functions in three samples: clinically heterogeneous adolescents (Study 1: N = 457), transdiagnostic adults (Study 2: N = 145), and adults with acute or recently weight-restored anorexia nervosa (Study 3: N = 45). Study 1 indicated the four-function model was a good fit for restricting (root mean square error of approximation [RMSEA] = .06, Tucker-Lewis index [TLI] = .88). This factor structure replicated in Study 2 (comparative fit index [CFI] = .97, RMSEA = .07, TLI = .97, standardized root mean square residual [SRMR] = .09). Unlike NSSI, binge eating, and purging, which have been found to primarily serve automatic negative reinforcement functions, all three present studies found automatic positive reinforcement was most highly endorsed (by up to 85% of participants). In Studies 1 and 3, automatic functions were associated with poorer emotion regulation (ps < .05). In Study 1, social functions were associated with less social support (ps < .001). Across studies, automatic functions were associated with greater restriction ps < .05). Functions varied slightly by ED diagnosis. Across ED presentation, severity, and developmental stage, restrictive eating may be largely maintained by automatic positive reinforcement, with some variability across presentations. Continued examination of restrictive eating functions will establish processes that maintain restriction, allowing more precise treatment targeting for these problematic behaviors. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

An empirical taxonomy of reward response patterns in a transdiagnostic eating disorder sample.

Reward response patterns may contribute to risk and maintenance of eating disorders (EDs), and there may be clinically meaningful heterogeneity in behavioral responses to different actual and anticipated rewards across ED diagnoses. We used an empirical approach to classify individuals with EDs based on self-reported tendencies for responding to reward-related stimuli. Latent profile analysis was conducted in a transdiagnostic ED sample (N = 104) using Temperament and Character Inventory (Cloninger et al., 1993) subscales to categorize participants on reward responses of behavioral activation towards immediate, hedonic rewards (Novelty Seeking subscale), persistence towards long-term rewards (Persistence subscale), and maintenance by social rewards (Reward Dependence subscale) rewards. Two profiles were identified: (1) Behavioral Activation group (elevated Novelty Seeking; n = 62); and (b) Behavioral Persistence group (elevated Persistence; n = 42). Generalized linear models comparing profiles showed that frequency of these reward response profiles did not differ in probable AN, BN, or OSFED groups; however, individuals with probable BED more often demonstrated the Behavioral Activation profile (p = .041). These profiles exhibited comparable ED severity, but different presentations. Across probable ED diagnoses, the Behavioral Activation group reported greater binge eating (p = .006, d = 0.32) and had higher BMIs (p = .001, d = 0.57); the Behavioral Persistence group endorsed greater driven exercise (p = .042, d = 0.33). Categorization by activation to novel, immediate rewards versus persistence towards long-term rewards was associated with different symptoms across diagnoses, potentially supporting the role of specific reward response profiles in ED phenomenology.

Adapting a neuroscience-informed intervention to alter reward mechanisms of anorexia nervosa: a novel direction for future research.

Accumulating psychobiological data implicate reward disturbances in the persistence of anorexia nervosa (AN). Evidence suggests that individuals with AN demonstrate decision-making deficits similar to those with mood and anxiety disorders that cause them to under-respond to many conventionally rewarding experiences (e.g., eating, interacting socially). In contrast, unlike individuals with other psychiatric disorders, individuals with AN simultaneously over-respond to rewards associated with eating-disorder behaviors (e.g., restrictive eating, exercising). This pattern of reward processing likely perpetuates eating-disorder symptoms, as the rewards derived from eating-disorder behaviors provide temporary relief from the anhedonia associated with limited responsivity to other rewards. Positive Affect Treatment (PAT) is a cognitive-behavioral intervention designed to target reward deficits that contribute to anhedonia in mood and anxiety disorders, including problems with reward anticipation, experiencing, and learning. PAT has been found to promote reward responsivity and clinical improvement in mood and anxiety disorders. This manuscript will: (1) present empirical evidence supporting the promise of PAT as an intervention for AN; (2) highlight nuances in the maintaining processes of AN that necessitate adaptations of PAT for this population; and (3) suggest future directions in research on PAT and other reward-based treatments that aim to enhance clinical outcomes for AN.

Past research has shown that people with anorexia nervosa (AN) have trouble experiencing positive emotions in response to many common life events (e.g., socializing, winning money). This tendency to under-respond to positive events is similar to that found in people with mood and anxiety disorders. However, people with AN also appear to feel more positive emotions when they think about or engage in eating-disorder behaviors (e.g., cutting back on their eating, exercising, thinking about being very thin). For this reason, people with AN may continually turn to eating-disorder behaviors, rather than other actions, to feel good about themselves and their lives. In this paper, we describe a new treatment, Positive Affect Treatment (PAT), that we believe has the potential to help individuals with AN gain more happiness and fulfillment from their lives outside of their eating disorder. Our expectation is that such a change may result in individuals with AN no longer needing their eating disorder to feel good.

Neurobiological and Psychological Maintenance Mechanisms Associated with Anticipatory Reward in Bulimia Nervosa.

The purpose of this investigation is to identify the anticipatory reward mechanisms that maintain binge eating and purging in bulimia nervosa. Emerging data indicate the importance of reward and anticipatory processes as maintenance mechanisms of bulimia nervosa that can be targeted in treatment. The proposed research will identify neurobiological and psychological anticipatory mechanisms of binge eating and purging using functional magnetic resonance imaging (fMRI), and ecological momentary assessment (EMA) in the natural environment. In this investigation, 60 adults (30 with bulimia nervosa and 30 matched comparison participants) will undergo negative and positive mood inductions followed by an fMRI food selection task (and a comparison shopping task) to examine neurobiological and affective responses to food and non-food reward anticipation. Participants with bulimia nervosa will complete two weeks of EMA examining real-time affect changes in relation to the anticipation of binge eating and purging. These methods will facilitate rigorous assessment of the links between neurobiological (fMRI) and naturalistic (EMA) data in anticipatory reward processes. Findings from this investigation will inform the conceptualization and treatment of bulimia nervosa by identifying the role of reward anticipation in symptom maintenance, providing a crucial framework for targeting these anticipatory processes in existing and novel interventions.

Resting State Hypoconnectivity of Reward Networks in Binge Eating Disorder.

The clinical presentation of binge eating disorder (BED) and data emerging from task-based functional neuroimaging research suggests that this disorder may be associated with alterations in reward processing. However, there is a dearth of research investigating the functional organization of brain networks that mediate reward in BED. To address this gap, 27 adults with BED and 21 weight-matched healthy controls (WMC) completed a multimodel assessment consisting of a resting functional magnetic resonance imaging scan, behavioral tasks measuring reward-based decision-making (i.e., delay discounting and reversal learning), and self-report assessing clinical symptoms. A seed-based approach was employed to examine the resting state functional connectivity (rsFC) of the striatum (nucleus accumbens [NAcc] and ventral and dorsal caudate), a collection of regions implicated in reward processing. Compared with WMC, the BED group exhibited lower rsFC of striatal seeds, with frontal regions mediating executive functioning (e.g., superior frontal gyrus [SFG]) and posterior, parietal, and temporal regions implicated in emotional processing. Lower NAcc-SFG rsFC was associated with more difficulties with reversal learning and binge eating frequency in the BED group. Results suggest that hypoconnectivity of striatal networks that integrate self-regulation and reward processing may promote the clinical phenomenology of BED. Interventions for BED may benefit from targeting these circuit-based disturbances.

Mixture Modeling to Characterize Anorexia Nervosa: Integrating Personality and Eating Disorder Psychopathology.

BACKGROUND: Efforts to examine alternative classifications (e.g., personality) of anorexia nervosa (AN) using empirical techniques are crucial to elucidate diverse symptom presentations, personality traits, and psychiatric comorbidities. AIMS: The purpose of this study was to use an empirical approach (mixture modeling) to test an alternative classification of AN as categorical, dimensional, or hybrid categorical-dimensional construct based on the co-occurrence of personality psychopathology and eating disorder clinical presentation. METHODS: Patients with AN (N = 194) completed interviews and questionnaires at treatment admission and 3-month follow-up. Mixture modeling was used to test whether indicators best classified AN as categorical, dimensional, or hybrid. RESULTS: A four-latent class, one-latent dimension mixture model that was variant across groups provided the best fit to the data. Results suggest that all classes were characterized by low self-esteem and self-harming and suicidality tendencies. Individuals assigned to Latent Class 2 (LC2; n = 21) had a greater tendency toward being impulsive and easily angered and having difficulties controlling anger compared with those in LC1 (n = 84) and LC3 (n = 66). Moreover, individuals assigned to LC1 and LC3 were more likely to have a poor outcome from intensive treatment compared with those in LC4 (n = 21). Findings indicate that the dimensional aspect within each class measured frequency of specific eating disorder behaviors but did not predict treatment outcomes. CONCLUSIONS: These results emphasize the complexity of AN and the importance of considering how facets of clinical presentation beyond eating disorder behaviors may have different treatment and prognostic implications.