A mechanistic staging model of reward processing alterations in individuals with binge-type eating disorders

Momentary mechanisms of binge-eating symptoms using ecological momentary assessment: The moderating role of food addiction

OBJECTIVE

Food addiction (FA) shows phenotypic and diagnostic overlap with eating disorders characterised by binge eating, though it is unknown how momentary processes driving binge-eating symptoms differ by FA. The present study examined the possible moderating influence of FA severity on momentary mechanisms underlying binge-eating symptomatology using ecological momentary assessment (EMA).

METHOD

Adults (N = 49, mean age = 34.9 ± 12.1, cis-gender female = 77.1%) who met criteria for FA and/or binge-eating disorder completed baseline measures including the Yale Food Addiction Scale (YFAS) followed by a 10-day EMA protocol. Generalised linear mixed models assessed main effects of YFAS, momentary antecedents (affect, impulsivity, food cue exposure, appetite, and eating expectancies) and two-way interactions between YFAS and within-person antecedents.

RESULTS

FA severity moderated momentary associations between food cue exposure and subsequent binge-eating symptoms: the association was stronger among participants with lower but not higher YFAS scores. No other interactions were significant.

CONCLUSIONS

Some functional associations underlying binge-eating symptoms vary based on individuals' level of FA symptoms. Future research to further understand how observed associations may differ amongst diverse populations and over course of illness may also inform future prevention and interventions.

Examining neural responses to anticipating or receiving monetary rewards and the development of binge eating in youth. A registered report using data from the Adolescent Brain Cognitive Development (ABCD) study

Binge eating is characterized as eating a large amount of food and feeling a loss of control while eating. However, the neurobiological mechanisms associated with the onset and maintenance of binge eating are largely unknown. Recent neuroimaging work has suggested that increased responsivity within reward regions of the brain to the anticipation or receipt of rewards is related to binge eating; however, limited longitudinal data has precluded understanding of the role of reward responsivity in the development of binge eating. The current study used data from the Adolescent Brain and Cognitive Development® (ABCD) longitudinal study dataset to assess whether heightened neural responses to different phases of reward processing (reward anticipation and receipt) (1) differentiated individuals with binge eating from matched controls, and (2) predicted the onset of binge eating in an "at risk" sample. Consistent with hypotheses, heightened neural responsivity in the right caudate and bilateral VS during reward anticipation differentiated youth with and without binge eating. Moreover, greater VS response to reward anticipation predicted binge eating two years later. Neural responses to reward receipt also were consistent with hypotheses, such that heightened VS and OFC responses differentiated youth with and without binge eating and predicted the presence of binge eating two years later. Findings from the current study suggest that hypersensitivity to rewards may contribute to the development of binge eating during early adolescence.

Alcohol use disorder and body mass index show genetic pleiotropy and shared neural associations

Background

The prevalence of co-occurring heavy alcohol consumption and obesity is increasing in the United States. Despite neurobiological overlap in the regulation of alcohol consumption and eating behavior, alcohol- and body mass index (BMI)-related phenotypes show no or minimal genetic correlation. We hypothesized that the lack of genetic correlation is due to mixed effect directions of variants shared by AUD and BMI.

Methods

We applied MiXeR, to investigate shared genetic architecture between AUD and BMI in individuals of European ancestry. We used conjunctional false discovery rate (conjFDR) analysis to detect loci associated with both phenotypes and their directional effect, Functional Mapping and Annotation (FUMA) to identify lead single nucleotide polymorphisms (SNPs), Genotype-Tissue Expression (GTEx) samples to examine gene expression enrichment across tissue types, and BrainXcan to evaluate the shared associations of AUD and BMI with brain image-derived phenotypes.

Results

MiXeR analysis indicated polygenic overlap of 80.9% between AUD and BMI, despite a genetic correlation (r g ) of -.03. ConjFDR analysis yielded 56 lead SNPs with the same effect direction and 76 with the opposite direction. Of the 132 shared lead SNPs, 53 were novel for both AUD and BMI. GTEx analyses identified significant overexpression in the frontal cortex (BA9), hypothalamus, cortex, anterior cingulate cortex (BA24), hippocampus, and amygdala. Amygdala and caudate nucleus gray matter volumes were significantly associated with both AUD and BMI in BrainXcan analyses.

Conclusions

More than half of variants significantly associated with AUD and BMI had opposite directions of effect for the traits, supporting our hypothesis that this is the basis for their lack of genetic correlation. Follow-up analyses identified brain regions implicated in executive functioning, reward, homeostasis, and food intake regulation. Together, these findings clarify the extensive polygenic overlap between AUD and BMI and elucidate several overlapping neurobiological mechanisms.

Staging models in eating disorders: A systematic scoping review of the literature

Eating Disorders (ED) are characterized by low remission rates, treatment drop-out, and residual symptoms. To improve assessment and treatment of ED, the staging approach has been proposed. This systematic scoping review is aimed at mapping the existing staging models that explicitly propose stages of the progression of ED. A systematic search of PubMed, PsycINFO, Scopus was conducted with the terms staging, anorexia nervosa, bulimia nervosa, binge-eating disorders, eating disorders. Eleven studies met inclusion criteria presenting nine ED staging models, mostly for anorexia nervosa. Three were empirically tested, one of which was through an objective measure specifically developed to differentiate between stages. Most staging models featured early stages in which the exacerbation of EDs unfolds and acute phases are followed by chronic stages. Intermediate stages were not limited to acute stages, but also residual phases, remission, relapse, and recovery. The criteria for stage differentiation encompassed behavioral, psychological, cognitive, and physical features including body mass index and illness duration. One study recommended stage-oriented interventions. The current review underscores the need to empirically test the available staging models and to develop and test new proposals of staging models for other ED populations. The inclusion of criteria based on medical features and biomarkers is recommended. Staging models can potentially guide assessment and interventions in daily clinical settings.

Task-Evoked Neural Activity During Reward Anticipation and Inhibitory Control in Preadolescent Binge Eating Disorder

PURPOSE

Behavioral features of binge eating disorder (BED) suggest abnormalities in reward and inhibitory control. Studies of adult populations suggest functional abnormalities in reward and inhibitory control networks. Despite behavioral markers often developing in children, the neurobiology of pediatric BED remains unstudied.

METHODS

Fifty eight preadolescent children (aged 9-10 years) with BED and 68 age, body mass index and developmentally matched control children were extracted from the 3.0 baseline (Year 0) release of the Adolescent Brain Cognitive Development Study. We investigated task-evoked blood-oxygen-level-dependent response during functional magnetic resonance imaging, as participants completed the monetary incentive delay task and the stop signal task. We indexed group differences in regions of interest in the reward (orbitofrontal cortex, nucleus accumbens) and inhibitory control (dorsolateral prefrontal cortex, anterior cingulate cortex).

RESULTS

No significant group differences emerged during tasks of inhibitory control among children with BED and children without BED. Similarly, no significant group differences emerged during the anticipation or receipt of reward among children with BED and children without BED.

DISCUSSION

Preadolescent children with BED do not demonstrate abnormal neural activity in prominent nodes of reward or inhibitory control circuitry during tasks of inhibitory control, reward anticipation, and reward receipt, relative to children without BED who also had a similar body mass index.

Neurocognitive reward processes measured via event-related potentials are associated with binge-eating disorder diagnosis and ecologically-assessed behavior

Altered reward processing has been implicated in the onset and maintenance of binge-eating disorder (BED). However, it is unclear which precise neurocognitive reward processes may contribute to BED. In the present study, 40 individuals with BED and 40 age-, sex-, and BMI-matched controls completed a reward (incentive delay) task while their neural activity was recorded using electroencephalography (EEG). Individuals with BED also completed a 10-day ecological momentary assessment (EMA) protocol assessing binge-eating behavior in the natural environment. Event-related potential (ERP) analysis of the EEG indicated that individuals with BED had stronger anticipatory (CNV) and outcome-related (RewP) neural reward activity to food and monetary rewards, compared to controls. However, within the BED group, greater frequency of binge eating during the EMA protocol was associated with stronger anticipatory (CNV) but weaker outcome-related (RewP) neural reward activity. These associations within the BED group were unique to food, and not monetary, rewards. Although preliminary, these results suggest that both anticipatory ("wanting") and outcome ("liking") reward processes may be generally amplified in BED. However, they also suggest that among individuals with BED, disorder severity may be associated with increased anticipatory reward processes ("wanting"), but relatively decreased reward-outcome processing ("liking"), of food rewards specifically.

The relationship between difficulties in the regulation of positive and negative emotions and binge-eating symptoms in young adults

It is well-established that binge-eating (BE) is linked to emotion regulation (ER) difficulties. However, research to date has focused almost exclusively on difficulties regulating negative emotions, with little attention to the relationship between positive emotion dysregulation and BE. Further, research is inconclusive regarding which specific facets of ER difficulties are most strongly associated with BE behaviour. Therefore, the current study examined whether difficulties regulating both negative as well as positive emotions explained unique variance in BE among young adults. The study also aimed to identify which particular dimensions of negative and positive ER difficulties were most strongly related to BE symptoms. Participants (N = 449) ages 18-25 completed self-report measures of difficulties regulating positive and negative emotions, BE symptoms, and psychological distress. Hierarchical regression analyses showed that BE was related to difficulties regulating both positive emotions and negative emotions, after controlling for psychological distress and BMI. Lack of emotional clarity and lack of access to ER strategies when faced with strong negative emotions were the facets of negative ER difficulties most strongly associated with BE. Impulsivity when experiencing strong positive emotions was the facet of positive ER difficulties most strongly associated with BE. These findings support the ER model of BE and suggest that difficulties regulating both positive and negative emotions contribute to BE among young adults.

Clinical staging across eating disorders: a scoping review protocol

INTRODUCTION

Clinical staging models in psychiatry assert that there are earlier, less severe or more malleable forms of illness that are distinguishable from later, more chronic forms of illness, and that these stages may have different prognostic and treatment implications. Previous reviews on clinical staging in eating disorders (EDs) suggest a staging heuristic could be useful for anorexia nervosa, but less research is available on how this applies to other EDs. An up-to-date review is required to synthesise new and heterogenous avenues of research. This scoping review aims to explore the extent and types of evidence in relation to illness staging for EDs and how these concepts are associated with treatment response and outcomes.

METHODS AND ANALYSIS

This protocol was developed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocol extension for Scoping Reviews checklist and the Joanna Briggs Institute Reviewer's Manual. We will consider any documents providing evidence for clinical staging such as those which describe full or partial staging models, for all EDs, across various domains of assessment and functioning. Participants will include clinical or non-clinical population samples with full-syndrome EDs or disordered eating behaviour. PubMed, PsycINFO, MEDLINE and Web of Science databases will be systematically searched for relevant literature. Two authors will export documents and screen titles, abstracts and full texts. Data will be extracted into a charting form drafted by the authors. A narrative summary of the documents will be conducted in line with the study aims. Finally, clinical and research recommendations will be outlined.

ETHICS AND DISSEMINATION

Ethical approval will not be required to synthesise published and unpublished literature. The study will be published in a peer-reviewed journal and shared at conferences, via social media, and in other communications.

Neuronal activity and reward processing in relation to binge eating

PURPOSE OF REVIEW

Studies increasingly show the importance of reward processing in binge eating and provide evidence of associated changes in the neurobiological reward system. This review gives an up-to-date overview of the neurobiological substrates of reward processing subconstructs in binge eating. Neural findings are linked to different behavioral theories and the clinical relevance is discussed.

RECENT FINDINGS

Increased neural responses in the orbitofrontal cortex, anterior cingulate cortex as well as striatum during anticipation and receipt of food rewards are found in association to binge eating. Increased model-free learning is also found and associated with altered brain reward reactivity. Data in rest report reduced striatal dopamine release and lower frontostriatal connectivity. Mechanisms of onset of binge eating are less clear, but specific personality traits, related to frontostriatal dysconnectivity, probably increase the risk of binge eating onset.

SUMMARY

Both structural and task-based imaging studies show differences in the neurobiological reward system in binge eating. These changes are linked to specific reward processing, such as altered reward responsiveness to food cues, reinforcement learning, and habitual behavior. Findings are lined with different behavioral theories of binge eating, and a staging model is described, from onset to full illness development. Understanding the specific underlying aberrant reward mechanism in binge eating, associated with different stages of the illness, enables caregivers to focus their treatment more precisely.

Be more mindful: Targeting addictive responses by integrating mindfulness with cognitive bias modification or cue exposure interventions

This review provides an overview of the most prominent neurocognitive effects of cognitive bias modification (CBM), cue-exposure therapy and mindfulness interventions for targeting addictive responses. It highlights the key insights that have stemmed from cognitive neuroscience and brain imaging research and combines these with insights from behavioural science in building a conceptual model integrating mindfulness with response-focused CBM or cue-exposure interventions. This furthers our understanding of whether and how mindfulness strategies may i) facilitate or add to the induced response-focused effects decreasing cue-induced craving, and ii) further weaken the link between craving and addictive responses. Specifically, awareness/monitoring may facilitate, and decentering may add to, response-focused effects. Combined awareness acceptance strategies may also diminish the craving-addiction link. The conceptual model presented in this review provides a specific theoretical framework to deepen our understanding of how mindfulness strategies and CBM or cue-exposure interventions can be combined to greatest effect. This is important in both suggesting a roadmap for future research, and for the further development of clinical interventions.

Integrating aspects of affect, reward, and cognition to develop more comprehensive models of binge-eating pathology

Reward-related processes are an increasing focus of eating disorders research. Although evidence suggests that numerous distinct reward processes may contribute to eating pathology (e.g., reward learning and delay discounting), existing etiological models of reward dysfunction tend to focus on only a limited number of reward processes, and frequently lack specificity when identifying the individual reward processes hypothesized to contribute to dysregulated eating behavior. Moreover, existing theories have been limited in their integration of reward-related processes with other demonstrated risk and maintenance factors for eating disorders (e.g., affect and cognition), potentially contributing to underdeveloped models of eating pathology. In this article, we highlight five distinct reward processes with theorized or demonstrated relevance to eating disorders involving binge-eating, followed by a review of two well-established risk/maintenance factors for binge-eating pathology. We then introduce two novel models of binge eating onset and maintenance that integrate these factors (i.e., the Affect, Reward, Cognition models), and discuss methods for testing each of the models in future research. Ultimately, we hope that the proposed models provide a springboard for the continued evolution of more precise and comprehensive theories of reward dysfunction in the eating disorders, as well as the development of novel intervention approaches. PUBLIC SIGNIFICANCE STATEMENT: Eating disorders are associated with abnormalities in multiple domains of reward functioning. However, models of reward dysfunction within the eating disorders have not been well-integrated with prominent models of affect and cognition. This article presents two novel models of onset and maintenance for binge-eating pathology, which attempt to integrate observed reward abnormalities with other affective and cognitive processes implicated in binge-type eating disorders.