Behavioral and neurodevelopmental precursors to binge-type eating disorders: support for the role of negative valence systems

Relationship between psychopathology and binge size in binge eating spectrum disorders

OBJECTIVE

Food intake during binge eating episodes (BEE) has been found to be associated with symptoms of depression and anxiety in individuals with eating disorders (EDs). The objective of this study was to evaluate the association between caloric intake during BEE and psychopathology in individuals with binge eating spectrum disorders (BSD).

METHODS

One-hundred and fourteen outpatients diagnosed with bulimia nervosa (BN) and binge eating disorder (BED) were sequentially assessed. The Mini International Neuropsychiatric Interview Plus (MINI PLUS) was used to assess psychiatric diagnoses. Validated self-report instruments were used to assess general and eating-related psychopathology. The Dietpro Clinical Program® was used for assessment of calorie consumption during BEE. Data were analyzed with independent Student's t tests, effect size (Cohen's d), and Pearson's correlation coefficients.

RESULTS

Participants with BSD comorbid with a depressive disorder consumed significantly more calories during BEE than those without depression. Furthermore, participants with BSD and higher levels of impulsivity had higher caloric intake during episodes. Specifically regarding BN, participants with greater disease severity consumed more calories during episodes than those with lesser severity.

CONCLUSION

Overall, depression and high impulsivity were associated with higher caloric intake during BEE in individuals with BSD. For those with BN, disease severity was associated with greater calorie consumption during episodes. Our results support the relevance of early identification of psychiatric comorbidities and implementation of strategies to control mood and impulsivity, aiming for better prognosis in the treatment of BSD.

Associations of food reinforcement and food- related inhibitory control with adiposity and weight gain in children and adolescents

Some, but not all studies have reported that, among youth with disordered eating and high weight, the relative reinforcing value of food (RRV-F, i.e., how hard a person will work for a high-energy-dense food when another reward is available) is greater, and food-related inhibitory control (i.e., ability to withhold a response to food-related stimuli) is lower, compared to peers without disordered eating or overweight. In most studies, high RRV-F and low food-related inhibitory control have been studied separately, as independent factors, with each suggested to predict excess weight and adiposity (fat mass) gain. We hypothesized that the interaction of these factors would prospectively exacerbate risk for weight and adiposity (fat mass) gain three years later in a sample of healthy youth. At baseline, RRV-F was measured using a Behavior Choice Task with the rewards being standardized servings of chocolate candies, cheese crackers, or fruit snacks. Food-related inhibitory control was determined by performance in response to food and non-food stimuli during a Food Go/No-Go task. At baseline and 3-year visits, total body adiposity was measured by dual-energy X-ray absorptiometry (DXA) and body mass index (BMI) was obtained using measured weight and height. A linear regression was conducted with 3-year adiposity as the dependent variable. RRV-F, food-related inhibitory control, and the RRV-F x food-related inhibitory control interaction as independent variables. Baseline adiposity, age, height, sex, race/ethnicity, and days between visits were included as covariates for model predicting 3-year adiposity. Baseline BMI, age, sex, race/ethnicity, and days between visits were included as covariates for model predicting 3-year BMI. One-hundred and nine youth (mean 12.4±2.7y, mean 0.50±1.02 BMIz, 30.3% with overweight/obesity, 45.9% female, 51.4% non-Hispanic White), 8-17 years at baseline, were studied. Baseline food-related inhibitory control (βunstandardized = 0.33, p = .037, 95% CI [.02, 0.64]), but not baseline RRV-F (βunstandardized = -0.003, p = .914), 95% CI [-0.05, 0.05]) was significantly associated with 3-year adiposity such that those with the poorest food-related inhibitory control (great number of commision errors) had the greatest adiposity gain. The interaction between RRV-F and food-related inhibitory control did not predict 3-year adiposity (βunstandardized = -0.07, p = .648, 95% CI [-0.39, 0.25]). The pattern of findings was the same for models examining non-food related inhibitory control. Neither baseline food-related inhibitory control (βunstandardized = 2.16, p = .256, 95% CI [-1.59, 5.92]), baseline RRV-F (βunstandardized = 0.14, p = .660, 95% CI [-0.48, 0.75]), nor their interaction (βunstandardized = -1.18, p = .547, 95% CI [-5.04, 2.69]) were significantly associated with 3-year BMI. However, non-food related inhibitory control (βunstandardized = 0.54, p = .038, 95% CI [.22, 7.15]) was significantly associated with 3-year BMI. In summary, food-related inhibitory control but not RRV-F, was associated with changes in adiposity in a sample of children and adolescents. Among generally healthy youth, food-related inhibitory control may be a more relevant risk factor than food reinforcement for adiposity gain. Additional data are needed to determine how inhibitory control and reward systems, as well as other disinhibited eating behaviors/traits, may interact to promote excess weight gain over time in youth.

Binge-Eating Precursors in Children and Adolescents: Neurodevelopment, and the Potential Contribution of Ultra-Processed Foods

Binge-eating disorder (BED) is a highly prevalent disorder. Subthreshold BED conditions (sBED) are even more frequent in youth, but their significance regarding BED etiology and long-term prognosis is unclear. A better understanding of brain findings associated with BED and sBED, in the context of critical periods for neurodevelopment, is relevant to answer such questions. The present narrative review starts from the knowledge of the development of emotional self-regulation in youth, and the brain circuits supporting emotion-regulation and eating behaviour. Next, neuroimaging studies with sBED and BED samples will be reviewed, and their brain-circuitry overlap will be examined. Deficits in inhibition control systems are observed to precede, and hyperactivity of reward regions to characterize, sBED, with overlapping findings in BED. The imbalance between reward/inhibition systems, and the implication of interoception/homeostatic processing brain systems should be further examined. Recent knowledge of the potential impact that the high consumption of ultra-processed foods in paediatric samples may have on these sBED/BED-associated brain systems is then discussed. There is a need to identify, early on, those sBED individuals at risk of developing BED at neurodevelopmental stages when there is a great possibility of prevention. However, more neuroimaging studies with sBED/BED pediatric samples are needed.

Disgust sensitivity and behavioural inhibitory systems in binge eating disorder: associations with eating pathology

Disgust sensitivity refers to how unpleasant a disgusting experience is to an individual and is involved in the development of many psychiatric conditions. Given its link with food ingestion, there is an interest in understanding how an individual's susceptibility to disgust relates to dietary habits. One possible mechanism giving rise to this association is through the effects negative emotions have on high-order cognitive processes, but few studies take this model into account. The aim of this study was to characterize general disgust sensitivity in a clinical binge eating disorder (BED) population, and explore whether disgust sensitivity relates to inhibitory control and eating pathology. Following a case-controlled study design, our results show that: (1) disgust sensitivity and its subscales do not differ between BED and healthy controls, (2) higher disgust sensitivity in BED relates to greater behavioural inhibition, (3) inhibitory control reaction times relate to aspects of eating pathology, and (4) inhibitory control does not mediate relationships between disgust sensitivity and BMI among participants with BED. Understanding the role of disgust sensitivity in BED may allow us to understand how negative emotion systems maintain dysregulated eating behaviours with the potential to inform emotion-regulation treatment approaches. Level of evidence: Level III: Evidence obtained from well-designed cohort or case-control analytic studies.

What next for eating disorder genetics? Replacing myths with facts to sharpen our understanding

Substantial progress has been made in the understanding of anorexia nervosa (AN) and eating disorder (ED) genetics through the efforts of large-scale collaborative consortia, yielding the first genome-wide significant loci, AN-associated genes, and insights into metabo-psychiatric underpinnings of the disorders. However, the translatability, generalizability, and reach of these insights are hampered by an overly narrow focus in our research. In particular, stereotypes, myths, assumptions and misconceptions have resulted in incomplete or incorrect understandings of ED presentations and trajectories, and exclusion of certain patient groups from our studies. In this review, we aim to counteract these historical imbalances. Taking as our starting point the Academy for Eating Disorders (AED) Truth #5 "Eating disorders affect people of all genders, ages, races, ethnicities, body shapes and weights, sexual orientations, and socioeconomic statuses", we discuss what we do and do not know about the genetic underpinnings of EDs among people in each of these groups, and suggest strategies to design more inclusive studies. In the second half of our review, we outline broad strategic goals whereby ED researchers can expand the diversity, insights, and clinical translatability of their studies.

Detecting negative valence symptoms in adolescents based on longitudinal self-reports and behavioral assessments

BACKGROUND

Given the high prevalence of depressive symptoms reported by adolescents and associated risk of experiencing psychiatric disorders as adults, differentiating the trajectories of the symptoms related to negative valence at an individual level could be crucial in gaining a better understanding of their effects later in life.

METHODS

A longitudinal deep learning framework is presented, identifying self-reported and behavioral measurements that detect the depressive symptoms associated with the Negative Valence System domain of the NIMH Research Domain Criteria (RDoC).

RESULTS

Applied to the annual records of 621 participants (age range: 12 to 17 years) of the National Consortium on Alcohol and Neurodevelopment in Adolescence (NCANDA), the deep learning framework identifies predictors of negative valence symptoms, which include lower extraversion, poorer sleep quality, impaired executive control function and factors related to substance use.

LIMITATIONS

The results rely mainly on self-reported measures and do not provide information about the underlying neural correlates. Also, a larger sample is required to understand the role of sex and other demographics related to the risk of experiencing symptoms of negative valence.

CONCLUSIONS

These results provide new information about predictors of negative valence symptoms in individuals during adolescence that could be critical in understanding the development of depression and identifying targets for intervention. Importantly, findings can inform preventive and treatment approaches for depression in adolescents, focusing on a unique predictor set of modifiable modulators to include factors such as sleep hygiene training, cognitive-emotional therapy enhancing coping and controllability experience and/or substance use interventions.

Benefits of Exercise in Multidisciplinary Treatment of Binge Eating Disorder in Adolescents with Obesity

Obesity in childhood and adolescence represents a serious health problem worldwide. Similarly, eating disorders (EDs) are complex diseases that affect adolescents with an increasing prevalence and are an alarming health concern to both physical and mental health. Traditionally, obesity and EDs, particularly binge eating disorder (BED), have been considered separate conditions, but there is emerging evidence such as etiology, comorbidities, risk factors, psychosocial impairment, and prevention approaches, highlighting important overlaps among these conditions. In youth, the two conditions share risk factors and consequences at both the physical and psychological levels, requiring special care. Exercise, useful as strategy to prevent and treat overweight conditions, may have beneficial effects on BED symptoms, suggesting that it may be considered as one of the key factors in the treatment of individuals affected by obesity with BED. The purpose of this narrative review is to examine the bidirectional impact of obesity and BED in adolescents, in terms of risk factors, etiology and comorbid conditions. Specifically, we focused on the benefits of physical activity (PA) in the multidisciplinary treatment of subjects affected by obesity with BED. Even though additional research is needed to reach conclusions about the role of exercise in the treatment of obesity and comorbid BED, especially in adolescents, promising results have already suggested that closely monitored exercise is safe and, paired with cognitive behavioral therapy, may provide multiple benefits on both the physical and psychological levels. Tailored and integrated treatments for weight management and eating disorders are important to promptly and effectively treat obese subjects that have BED.

Volume and Connectivity Differences in Brain Networks Associated with Cognitive Constructs of Binge Eating

Bulimia nervosa (BN) and binge eating disorder (BED) are characterized by episodes of eating large amounts of food while experiencing a loss of control. Recent studies suggest that the underlying causes of BN/BED consist of a complex system of environmental cues, atypical processing of food stimuli, altered behavioral responding, and structural/functional brain differences compared with healthy controls (HC). In this narrative review, we provide an integrative account of the brain networks associated with the three cognitive constructs most integral to BN and BED, namely increased reward sensitivity, decreased cognitive control, and altered negative affect and stress responding. We show altered activity in BED/BN within several brain networks, specifically in the striatum, insula, prefrontal cortex (PFC) and orbitofrontal cortex (OFC), and cingulate gyrus. Numerous key nodes in these networks also differ in volume and connectivity compared with HC. We provide suggestions for how this integration may guide future research into these brain networks and cognitive constructs.

Trait self-control and disinhibited eating in COVID-19: The mediating role of perceived mortality threat and negative affect

As the coronavirus disease 2019 (COVID-19) spreads globally, people are at risk of developing disinhibited eating behaviors. This study aimed to examine whether perceived mortality threat and negative affect mediate the relationship between trait self-control and disinhibited eating during the pandemic. A longitudinal survey was administered to a sample of college students (N = 634) before the outbreak (September 2019, T1), during the mid-term (February 2020, T2), and in the later stage of the pandemic (April 2020, T3). Self-report measures of trait self-control (T1), perceived mortality threat (T2, T3), negative affect (T2, T3), and disinhibited eating (T2, T3) were successively completed. Trait self-control was found to be negatively associated with negative affect, perceived mortality threat, and disinhibited eating during the mid-term and later stage of the pandemic. Disinhibited eating was positively associated with negative affect and perceived mortality threat. The longitudinal mediation results demonstrated that trait self-control (T1) could negatively predict disinhibited eating (T3) through negative affect (T2) rather than through perceived mortality threat. These findings suggest that trait self-control is of great importance in regulating psychological discomfort and disinhibited eating during stressful periods and that negative affect might be the main psychological mechanism underlying the relationship between self-control ability and disinhibited eating.

The Role of Negative Affect in Emotional Processing of Food-Related Images in Eating Disorders and Obesity

The aim of the present study was to analyze differences in the emotional processing (valence, arousal, and dominance) of food-related information in patients with eating disorders (ED), patients with obesity, and healthy women. Moreover, the mediator role of negative affect and the moderating role of the diagnostic group (ED vs. non-ED) were analyzed.

METHOD

The sample consisted of 94 women (39 with eating disorders, 19 with obesity, and 36 healthy participants).

MEASURES

International Affective Picture System (IAPS) food picture exposure task; Self-Assessment Manikin Analog-Visual Scale (SAM) appraising Arousal, Valence, and Dominance; Eating Attitudes Test (EAT-26); Positive and Negative Affect Schedule (PANAS).

RESULTS

Patients with purging symptomatology rated food images as more unpleasant than healthy women. Patients with purging and restrictive eating symptomatology showed higher levels of arousal and less dominance over the emotions experienced, compared to patients with obesity and healthy women. The mediation analysis showed that negative affect mediated the relationship between eating symptomatology (EAT-26) and the Valence of food images, as well as the control over the emotions experienced when viewing food images (Dominance). For the moderation analysis participants were regrouped into two groups (ED patients vs. non-ED patients). The direct relationship between eating symptomatology and food image valence was moderated by the diagnostic group. However, the group did not moderate the direct relationship between the EAT-26 and dominance over experienced emotions, or the indirect effect on eating symptomatology through negative affect. These results show the relevance of negative affect in the emotional processing of food-related information, and they support an eating disorder-disordered eating dimensional perspective.

Anxiety, stress, and binge eating tendencies in adolescence: a prospective approach

BACKGROUND

Recent years have witnessed an increasing prevalence of binge eating tendencies in adolescence-warranting a clearer understanding of their underlying predisposing and precipitating factors. The current study investigated whether the interaction between high levels of anxiety and stress predicted increased levels of binge eating tendencies in a prospective cohort of adolescents (N = 324).

METHODS

Measurements were taken over three waves (M ages: 13.33, 14.48, 15.65) as part of the CogBIAS Longitudinal Study. Longitudinal associations between levels of anxiety and stress with binge eating tendencies were estimated using a random intercept cross-lagged panel model (RI-CLPM), which calculates within-person fluctuations over time while accounting for individual trait-like stability and between-person variations. Binge eating tendencies were measured by the Cognitive Restraint, Uncontrolled Eating, and Emotional Eating styles from the Three-Factor Eating Questionnaire-R18. Two models were created for each binge eating tendencies variable: (1) a basic model with anxiety and stress as independent variables; (2) an interaction model with an additional anxiety*stress interaction term. Model fit was assessed by SEM fit indices: X², CFI, NFI, TLI, RMSEA, SRMR. Superior model fit was ascertained by a chi-square difference test (p < .05).

RESULTS

For Cognitive Restraint, the interaction model demonstrated superior fit to the data (p < .05). The anxiety*stress interaction at Waves 1 and 2 was significantly negatively associated with Cognitive Restraint at Waves 2 (β = -0.18, p = .002) and 3 (β = -0.14, p = .002)-suggesting that anxiety and stress interacted to predict increased binge eating tendencies linked with cognitive restraint over and above their independent effects. In contrast, the interaction term between anxiety*stress did not predict levels of Uncontrolled Eating or Emotional Eating over time.

CONCLUSIONS

The results highlight the importance of increasing awareness of the interaction between concurrently high anxiety and stress as a potential risk factor for binge eating tendencies in young people.

TRIAL REGISTRATION

Not applicable.

Network investigation of eating disorder symptoms and positive and negative affect in a clinical eating disorder sample

OBJECTIVE

Growing literature suggests that emotions influence the maintenance of eating disorder (ED) symptoms. However, most research has studied the relationship between ED symptoms and affect broadly (i.e., negative affect [NA], positive affect [PA]), rather than examining models comprised of multiple specific affective states (e.g., upset, proud).

METHOD

The current study (N = 196 individuals with EDs) used network analysis to examine the most interconnected (i.e., central) NA and PA states in EDs and test the complex associations between specific NA, PA, and ED symptoms. We estimated two networks: one with affective states only and another with affective states and ED symptoms.

RESULTS

Feeling distressed, afraid, attentive, and determined were the most central symptoms in the affect-only network. ED symptoms related to overvaluation of weight and shape, including affect-based ED symptoms (i.e., guilt about eating), were central in the network of affect and ED symptoms. Guilt about eating and shame were central bridge symptoms across affect and ED symptom clusters, meaning that they were each strongly connected across clusters, and may represent important pathways among affect and ED symptoms.

DISCUSSION

Limitations include the cross-sectional and between-person nature of these analyses, from which we cannot derive causal or within-persons processes. Clinical interventions that target central and bridge symptoms (e.g., fear, shame) may disrupt the reinforcing cycle of NA in EDs that may contribute to ED behaviors. Future research should examine relationships among affective states and ED symptoms in longitudinal and intraindividual network models to develop more effective treatments for EDs.

Systems genetic analysis of binge-like eating in a C57BL/6J x DBA/2J-F2 cross

Binge eating is a heritable trait associated with eating disorders and refers to the rapid consumption of a large quantity of energy-dense food that is, associated with loss of control and negative affect. Binge eating disorder is the most common eating disorder in the United States; however, the genetic basis is unknown. We previously identified robust mouse inbred strain differences between C57BL/6J and DBA/2J in binge-like eating of sweetened palatable food in an intermittent access, conditioned place preference paradigm. To map the genetic basis of changes in body weight and binge-like eating (BLE) and to identify candidate genes, we conducted quantitative trait locus (QTL) analysis in 128 C57BL/6J x DBA/2J-F2 mice combined with PheQTL and trait covariance analysis in GeneNetwork2 using legacy BXD-RI trait datasets. We identified a QTL on Chromosome 18 influencing changes in body weight across days in females (log of the odds [LOD] = 6.3; 1.5-LOD: 3-12 cM) that contains the candidate gene Zeb1. We also identified a sex-combined QTL influencing initial palatable food intake on Chromosome 5 (LOD = 5.8; 1.5-LOD: 21-28 cM) that contains the candidate gene Lcorl and a second QTL influencing escalated palatable food intake on Chromosome 6 in males (LOD = 5.4; 1.5-LOD: 50-59 cM) that contains the candidate genes Adipor2 and Plxnd1. Finally, we identified a suggestive QTL in females for slope of BLE on distal Chromosome 18 (LOD = 4.1; p = 0.055; 1.5-LOD: 23-35 cM). Future studies will use BXD-RI strains to fine map loci and support candidate gene nomination for gene editing.

Effects of a mindfulness-induction on subjective and physiological stress response in adolescents at-risk for adult obesity

BACKGROUND

Mindfulness-training may benefit stress response and stress-eating, yet few studies have experimentally tested these effects in adolescents. In this short communication, we report whether a brief mindfulness-induction affected acute stress response and stress-eating in adolescents at-risk for adult obesity. We explored disordered eating as a moderator.

METHOD

Twenty-nine adolescents (age 14 ± 2 y) at-risk for adult obesity participated in a within-subjects, randomized crossover experiment. Following a 10-minute mindfulness or neutral-induction on different days in random order, the Trier Social Stress Test adapted for adolescents was administered, followed by an ad libitum lunch meal. Physiological stress response (heart rate, blood pressure) and subjective stress response (anxiety, mindlessness) were determined with area under the curve with respect to increase. Stress-eating was measured as test meal energy consumed. Global disordered-eating and binge-eating were assessed with the Eating Disorders Examination-Questionnaire.

RESULTS

Relative to a neutral-induction, a mindfulness-induction reduced state anxiety response (p = .04). There were significant interactions of induction-type by global disordered-eating (p = .02) and binge-eating (p = .03), such that the mindfulness-induction most reduced anxiety response in adolescents with relatively lower global disordered-eating and those with no binge-eating. Induction-type also interacted with binge-eating in predicting diastolic blood pressure (p = .03). A mindfulness-induction, versus neutral-induction, most reduced diastolic blood pressure response in adolescents with binge-eating.

CONCLUSIONS

Brief mindfulness-training may alter some aspects of acute stress response, with variations by disordered-eating. Future research should test alternative mindfulness induction-types (e.g., acceptance/self-compassion) to improve our understanding of how mindfulness-training may benefit adolescents at-risk for adult obesity.

What are the emotions underlying feeling fat and fear of weight gain?

BACKGROUND

Eating disorders (EDs) are most always accompanied by cognitive-affective comorbidities, such as anxiety and depression. In addition to these common comorbidities, EDs are unique in that they are characterized by affective symptoms centered on body image and weight. Two of these primary, yet understudied, affective symptoms are feelings of fatness and fears of weight gain, which are theorized to be maintaining symptoms of EDs and are highly common in those with EDs. Despite the importance of these symptoms, there is no research characterizing which cognitive-affective symptoms contribute to feelings of fatness and fears of weight gain.

METHODS

The current study (N=168 individuals with an ED) tested cross-sectional and prospective models of cognitive-affect variables (negative affect, guilt, shame, fear of negative evaluation, anxiety sensitivity, and depression) to identify which thoughts and emotions were uniquely associated and prospectively predicted feelings of fatness and fear of weight gain.

RESULTS

Depression both cross-sectionally and prospectively predicted feeling fat over and above all other forms of affect. Fears of negative evaluation and depression were uniquely associated with fears of weight gain, and shame prospectively predicted fear of weight gain.

LIMITATIONS

Variables were self-reported, and the sample primarily consisted of women. Fear of weight gain and feelings of fatness were assessed using single items.

CONCLUSIONS

This research suggests that depression may be an important intervention target when individuals with an ED report feeling fat. Additionally, treatment targeting fear of negative evaluation, depression, and shame may decrease fears of weight gain.

A developmental framework of binge-eating disorder based on pediatric loss of control eating

Although binge-eating disorder may manifest in childhood, a significantly larger proportion of youth report episodes involving a loss of control while eating, the hallmark feature of binge eating that predicts excess weight gain and obesity. Adults with binge-eating disorder often report that symptoms emerged during childhood or adolescence, suggesting that a developmental perspective of binge eating may be warranted. Thus, loss of control eating may be a marker of prodromal binge-eating disorder among certain susceptible youth. The present article offers a broad developmental framework of binge-eating disorder and proposes areas of future research to determine which youths with loss of control eating are at risk for persistent and exacerbated behavior that may develop into binge-eating disorder and adult obesity. To this end, this article provides an overview of loss of control eating in childhood and adolescence, including its characterization, etiology, and clinical significance, with a particular focus on associations with metabolic risk, weight gain, and obesity. A conceptual model is proposed to further elucidate the mechanisms that may play a role in determining which youths with loss of control are at greatest risk for binge-eating disorder and obesity. Ways in which treatments for adult binge-eating disorder may inform approaches to reduce loss of control eating and prevent excess weight gain in youth are discussed. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

Neuroendocrinology of reward in anorexia nervosa and bulimia nervosa: Beyond leptin and ghrelin

The pathophysiology of anorexia nervosa (AN) and bulimia nervosa (BN) are still poorly understood, but psychobiological models have proposed a key role for disturbances in the neuroendocrines that signal hunger and satiety and maintain energy homeostasis. Mounting evidence suggests that many neuroendocrines involved in the regulation of homeostasis and body weight also play integral roles in food reward valuation and learning via their interactions with the mesolimbic dopamine system. Neuroimaging data have associated altered brain reward responses in this system with the dietary restriction and binge eating and purging characteristic of AN and BN. Thus, neuroendocrine dysfunction may contribute to or perpetuate eating disorder symptoms via effects on reward circuitry. This narrative review focuses on reward-related neuroendocrines that are altered in eating disorder populations, including peptide YY, insulin, stress and gonadal hormones, and orexins. We provide an overview of the animal and human literature implicating these neuroendocrines in dopaminergic reward processes and discuss their potential relevance to eating disorder symptomatology and treatment.

Combining cognitive bias modification training (CBM) and transcranial direct current stimulation (tDCS) to treat binge eating disorder: study protocol of a randomised controlled feasibility trial

INTRODUCTION

Binge eating disorder (BED) is a common mental disorder, closely associated with obesity. Existing treatments are only moderately effective with high relapse rates, necessitating novel interventions. This paper describes the rationale for, and protocol of, a feasibility randomised controlled trial (RCT), evaluating the combination of transcranial direct current stimulation (tDCS) and a computerised cognitive training, namely approach bias modification training (ABM), in patients with BED who are overweight or obese. The aim of this trial is to obtain information that will guide decision-making and protocol development in relation to a future large-scale RCT of combined tDCS+ABM treatment in this group of patients, and also to assess the preliminary efficacy of this intervention.

METHODS AND ANALYSIS

66 participants with Diagnostic and Statistical Manual-5 diagnosis of BED and a body mass index (BMI) of ≥25 kg/m2 will be randomly allocated to one of three groups: ABM+real tDCS; ABM+sham tDCS or a wait-list control group. Participants in both intervention groups will receive six sessions of ABM+real/sham tDCS over 3 weeks; engaging in the ABM task while simultaneously receiving bilateral tDCS to the dorsolateral prefrontal cortex. ABM is based on an implicit learning paradigm in which participants are trained to enact an avoidance behaviour in response to visual food cues. Assessments will be conducted at baseline, post-treatment (3 weeks) and follow-up (7 weeks post-randomisation). Feasibility outcomes assess recruitment and retention rates, acceptability of random allocation, blinding success (allocation concealment), completion of treatment sessions and research assessments. Other outcomes include eating disorder psychopathology and related neurocognitive outcomes (ie, delay of gratification and inhibitory control), BMI, other psychopathology (ie, mood), approach bias towards food and surrogate endpoints (ie, food cue reactivity, trait food craving and food intake).

ETHICS AND DISSEMINATION

This study has been approved by the North West-Liverpool East Research Ethics Committee. Results will be published in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

ISRCTN35717198.

Recent advances in therapies for eating disorders

Eating disorders are serious psychiatric illnesses with high rates of morbidity and mortality. Effective treatments have traditionally included behaviorally focused therapies as well as several medication strategies. Recent years have seen promising developments in these treatments, including additional support for family-based approaches for children and adolescents, new evidence for "third-wave" behavioral therapies, and new support for the use of lisdexamfetamine for binge eating disorder and olanzapine for anorexia nervosa. Case study and pilot data are beginning to show limited support for neuromodulatory interventions targeting brain regions thought to be involved in eating disorders. This review summarizes treatment developments over the last several years and points towards future directions for the field.

Loss-of-Control Eating and Obesity Among Children and Adolescents

PURPOSE OF REVIEW

This review summarizes findings on pediatric loss-of-control (LOC) eating and obesity published since 2013 in relation to physiological, socioenvironmental, and psychological factors.

RECENT FINDINGS

LOC eating and obesity are highly comorbid in youth. Genetic and physiological risk factors are associated with the development of LOC eating. Adverse physiological outcomes of LOC eating include increased risk for overweight and obesity and greater dysfunction in components of metabolic syndrome. Socioenvironmental, psychological, and behavioral factors, such as weight-based teasing, dieting, negative affect, emotion dysregulation, and aspects of cognitive functioning, are consistently related to LOC eating in youth, independent of weight. Prospectively, LOC eating may predict the onset of anxiety disorders, depression, and more severe eating psychopathology later in life. Updates on interventions and future directions are discussed. LOC eating may be a key symptom to target adverse physiological and psychological outcomes; however, treatments are limited and require further examination.

The Cognitive Drivers of Compulsive Eating Behavior

Compulsivity is a central feature of obsessive-compulsive and addictive disorders, which share considerable overlap with excessive eating in terms of repetitive behavior despite negative consequences. Excessive eating behavior is characteristic of several eating-related conditions, including eating disorders [bulimia nervosa (BN), binge eating disorder (BED)], obesity, and food addiction (FA). Compulsivity is proposed to be driven by four distinct cognitive components, namely, contingency-related cognitive flexibility, task/attentional set-shifting, attentional bias/disengagement and habit learning. However, it is unclear whether repetitive behavior in eating-related conditions is underpinned by deficits in these cognitive components. The current mini-review synthesizes the available evidence for performance on compulsivity-related cognitive tasks for each cognitive domain among populations with excessive eating behavior. In three of the four cognitive domains, i.e., set-shifting, attentional bias and habit learning, findings were mixed. Evidence more strongly pointed towards impaired contingency-related cognitive flexibility only in obesity and attentional bias/disengagement deficits only in obesity and BED. Overall, the findings of the reviewed studies support the idea that compulsivity-related cognitive deficits are common across a spectrum of eating-related conditions, although evidence was inconsistent or lacking for some disorders. We discuss the theoretical and practical importance of these results, and their implications for our understanding of compulsivity in eating-related conditions.

The potential of calibrated fMRI in the understanding of stress in eating disorders

Eating disorders (ED), including Anorexia Nervosa (AN), Bulimia Nervosa (BN), and Binge Eating Disorder (BED), are medically dangerous psychiatric disorders of unknown etiology. Accumulating evidence supports a biopsychosocial model that includes genetic heritability, neurobiological vulnerability, and psychosocial factors, such as stress, in the development and maintenance of ED. Notably, stress hormones influence appetite and eating, and dysfunction of the physiological stress response has been implicated in ED pathophysiology. Stress signals also appear associated with food reward neurocircuitry response in ED, providing a possible mechanism for the role of stress in appetite dysregulation. This paper provides a review of some of the interacting psychological, behavioral, physiological, and neurobiological mechanisms involved in the stress response among individuals with ED, and discusses novel neuroimaging techniques to address potential physiological confounds of studying neural correlates of stress in ED, such as calibrated fMRI.

Working toward precision medicine approaches to treat severe obesity in adolescents: report of an NIH workshop

Adolescent severe obesity is a prevalent, chronic, and serious disease with few effective and safe treatment options. To address this issue, a National Institutes of Health-sponsored workshop entitled "Developing Precision Medicine Approaches to the Treatment of Severe Obesity in Adolescents," was convened, bringing together a multidisciplinary group of experts to review the current state of the science and identify (1) what is known regarding the epidemiology and biopsychosocial determinants of severe obesity in adolescents, (2) what is known regarding effectiveness of treatments for severe obesity in adolescents and predictors of response, and (3) gaps and opportunities for future research to develop more effective and targeted treatments for adolescents with severe obesity. Major topical areas discussed at the workshop included: appropriate BMI metrics, valid measures of phenotypes and predictors, mechanisms associated with the development of severe obesity, novel treatments informed by biologically and psychosocially plausible mechanisms, biopsychosocial phenotypes predicting treatment response, standardization of outcome measures and results reporting in research, and improving clinical care. Substantial gaps in knowledge were identified regarding the basic behavioral, psychosocial, and biological mechanisms driving the development of severe obesity and the influence of these factors on treatment response. Additional exploratory and observational studies are needed to better understand the heterogeneous etiology of severe obesity and explain the high degree of variability observed with interventions. Tailored treatment strategies that may be developed by achieving a better understanding of individual differences in genetic endowment, clinical, metabolic, psychological, and behavioral phenotypes, and response to environmental exposures need to be tested. It is anticipated that these recommendations for future research, including strategies to enhance methodological rigor, will advance precision medicine approaches to treat severe obesity in adolescents more effectively.

Protective Factors Associated with Daily Affective Reactivity and Instability During Adolescence

The daily emotional experiences of adolescents are dynamic, vary significantly across individuals, and are crucial to their psychological adjustment, warranting a need to identify factors that promote adaptive affective responses to stressors and attenuated affective instability. The objective of this study, therefore, was to examine protective factors linked to individual differences in daily affective reactivity and instability utilizing a daily diary design in a national sample of 100 U.S. adolescents (13-17 years; 40% girls; 79% White). Adolescents completed a baseline survey and then 14 daily online surveys. Better mother-adolescent communication predicted lower negative affect reactivity, whereas greater use of problem-focused coping strategies predicted higher positive affect reactivity. Greater trait resilience and instrumental support seeking predicted lower negative affect instability. Conversely, more emotional support seeking predicted higher negative affect instability. No factors were associated with positive affect instability, and father-adolescent communication was unrelated to daily affective reactivity and instability. The findings implicate specific protective factors associated with distinct aspects of affective reactivity and instability.

Long-term safety and efficacy of guanfacine extended release in children and adolescents with ADHD

Data are reported from SPD503-318, a phase 3, open-label, safety study of guanfacine extended release (GXR) in European children and adolescents with attention-deficit/hyperactivity disorder (ADHD). Participants received dose-optimized GXR (1-7 mg/day) for up to 2 years. Of 215 enrolled participants, 214 were included in the safety population and 133 completed the study. Participants' mean age was 11.7 years and 73.8% were male. Overall, 177 participants (82.7%) experienced a treatment-emergent adverse event (TEAE). TEAEs reported in at least 10% of participants were somnolence (36.0%), headache (28.5%), fatigue (20.1%), and nasopharyngitis (11.7%). Serious TEAEs were reported in 4.7% of participants and TEAEs leading to discontinuation were reported in 3.3% of participants. There were no deaths. Mean z-scores for BMI were stable throughout the study. The incidence of sedative TEAEs (somnolence, sedation, and hypersomnia) peaked during week 3 and decreased thereafter. Small changes from baseline to the final assessment in mean supine pulse [- 5.5 bpm (standard deviation, 12.98)] and blood pressure [systolic, 0.6 mmHg (9.32); diastolic, 0.2 mmHg (9.17)] were reported. ADHD symptoms initially decreased and remained significantly lower than baseline at study endpoint. At the final assessment, the mean change in ADHD-RS-IV total score from baseline was - 19.8 (standard error of mean, 0.84; nominal p < 0.0001). In conclusion, GXR was well tolerated and more than 60% of participants completed the 2-year study.

Psychometric properties of the brief loss of control over eating scale (LOCES-B) in early adolescents

OBJECTIVE

The purpose of this study was to evaluate the psychometric properties of the brief loss of control over eating scale (LOCES-B) in a community sample of adolescents.

METHOD

Participants were 1,116 adolescents (11-15 years; 53% girls; 53% non-Hispanic White) recruited from middle schools in the Northeast United States. Participants were administered self-report surveys during school in the fall of 2016.

RESULTS

Confirmatory factor analyses indicated that the LOCES-B total score was unidimensional, which was invariant across gender and weight status. The LOCES-B had excellent internal consistency (α = .92). The LOCES-B total score had large, positive relationships with the frequency of LOC eating episodes, objective bulimic episodes, and subjective bulimic episodes, and a small, positive relationship with objective overeating episode frequency. After adjusting for demographics, anthropometrics, and LOC eating frequency, adolescents reporting higher scores on the LOCES-B total score had greater body image dissatisfaction, more internalizing symptoms, and lower trait effortful control.

DISCUSSION

Findings suggested that the LOCES-B is a reliable and valid measure of LOC eating in early adolescents. The availability of the LOCES-B has the potential to elucidate the developmental trajectories, predictors, and outcomes of LOC eating across the full severity spectrum in large cohort studies of youth.

Neuromodulation and neurofeedback treatments in eating disorders and obesity

PURPOSE OF REVIEW

Psychological interventions are the treatment of choice for most eating disorders; however, significant proportions of patients do not recover with these. Advances in understanding of the neurobiology of eating disorders have led to the development of targeted treatments, such as deep brain stimulation (DBS), noninvasive brain stimulation (NIBS), and neurofeedback. We review the emerging clinical evidence for the use of these interventions in eating disorders and obesity, together with their theoretical rationale. Finally, we reflect on future developments.

RECENT FINDINGS

During the last 20 months, seven case studies/series and seven randomized controlled trials (RCTs) of NIBS or neurofeedback in different eating disorders, obesity, or food craving have appeared. These have largely had promising results. One NIBS trial, using a multisession protocol, was negative. A case series of subcallosal DBS in anorexia nervosa has also shown promise. A search of trial registries identified a further 21 neuromodulation/feedback studies in progress, indicating that neuromodulation/feedback is an area of growing interest.

SUMMARY

At present, neuromodulation and neurofeedback are largely experimental interventions; however, growing understanding of the mechanisms involved, together with the rising number of studies in this area, means that the clinical utility of these interventions is likely to become clearer soon.

Hypothalamic CRF1 receptor mechanisms are not sufficient to account for binge-like palatable food consumption in female rats

OBJECTIVE

The present study evaluated the effect of systemic injection of the CRF1 receptor antagonist R121919, the corticosterone synthesis inhibitor metyrapone and central amygdala (CeA) injections of the nonselective CRF antagonist D-Phe-CRF_(12-41) in rats in which binge eating was evoked by stress and cycles of food restriction.

METHOD

Female rats were subjected or not to repeated cycles of regular chow food restriction/ad libitum feeding during which they were also given limited access (2 h) to palatable food. On the test day, rats were either exposed or not to the sight of the palatable food for 15 min without allowing access, before assessing food consumption.

RESULTS

Systemic injections of R121919, but not of the metyrapone, blocked binge-like eating behavior. Restricted and stressed rats showed up-regulation of crh1 receptor mRNA signal in the bed nucleus of the stria terminalis and CeA but not in basolateral amygdala (BLA) or in the paraventricular nucleus. Injection D-Phe-CRF_(12-41) in CeA but not in the BLA-blocked binge-like eating behavior.

DISCUSSION

These findings demonstrate that extra-hypothalamic CRF1 receptors, rather than those involved in endocrine functions, are involved in binge eating and the crucial role of CRF receptors in CeA. CRF1 receptor antagonism may represent a novel pharmacological treatment for binge-related eating disorders.

Estrogenic suppression of binge-like eating elicited by cyclic food restriction and frustrative-nonreward stress in female rats

Because binge eating and emotional eating vary through the menstrual cycle in human females, we investigated cyclic changes in binge-like eating in female rats and their control by estrogens. Binge-like eating was elicited by three cycles of 4 days of food restriction and 4 days of free feeding followed by a single frustrative nonreward-stress episode (15 min visual and olfactory exposure to a familiar palatable food) immediately before presentation of the palatable food. Intact rats showed binge-like eating during the diestrous and proestrous phases of the ovarian cycle, but not during the estrous (periovulatory) phase. Ovariectomized (OVX) rats not treated with estradiol (E2) displayed binge-like eating, whereas E2-treated OVX rats did not. The procedure did not increase signs of anxiety in an open-field test. OVX rats not treated with E2 that were subjected to food restriction and sacrificed immediately after frustrative nonreward had increased numbers of cells expressing phosphorylated extracellular signal-regulated kinases (ERK) in the central nucleus of the amygdala (CeA), paraventricular nucleus of hypothalamus (PVN), and dorsal and ventral bed nuclei of the stria terminalis (BNST) compared with nonrestricted or E2-treated rats. These data suggest that this female rat model is appropriate for mechanistic studies of some aspects of menstrual-cycle effects on emotional and binge eating in human females, that anxiety is not a sufficient cause of binge-like eating, and that the PVN, CeA, and BNST may contribute to information processing underlying binge-like eating.

Cortisol response to an induction of negative affect among adolescents with and without loss of control eating

BACKGROUND

Adults with binge eating disorder may have an exaggerated or blunted cortisol response to stress. Yet, limited data exist among youth who report loss of control (LOC) eating, a developmental precursor to binge eating disorder.

METHODS

We studied cortisol reactivity among 178 healthy adolescents with and without LOC eating. Following a buffet lunch meal adolescents were randomly assigned to watch a neutral or sad film clip. After, they were offered snacks from a multi-item array to assess eating in the absence of hunger. Salivary cortisol was collected at -80, 0, 30 and 50 min relative to film administration, and state mood ratings were reported before and after the film.

RESULTS

Adolescents with LOC had greater increases in negative affect during the experimental paradigm in both conditions (ps > 0.05). Depressive symptoms, but not LOC, related to a greater cortisol response in the sad film condition (ps > 0.05). Depressive symptoms and state LOC were related to different aspects of eating behaviour, independent of film condition or cortisol response (ps > 0.05).

CONCLUSIONS

A film clip that induced depressed state affect increased salivary cortisol only in adolescents with more elevated depressive symptoms. Adolescents with and without LOC were differentiated by greater increases in state depressed affect during laboratory test meals but had no difference in cortisol reactivity. Future studies are required to determine if adolescents with LOC manifest alterations in stress reactivity to alternative stress-inducing situations.

Advancing a Comprehensive Approach to the Study of Lower Urinary Tract Symptoms

PURPOSE

Lower urinary tract symptoms are common in the United States population, leading to significant economic, quality of life and public health issues. The burden will increase as the population ages, and risk factors for lower urinary tract symptoms, including diabetes and obesity, remain highly prevalent. Improving clinical management and establishing the knowledge base to prevent lower urinary tract symptoms will require a comprehensive research approach that examines factors beyond the lower urinary tract. While the study of extra-lower urinary tract factors has increased recently, current urological research does not systematically account for the broad set of potential contributing factors spanning biological, behavioral, psychological/executive function and sociocultural factors. A comprehensive assessment of potential contributors to risk, treatment response and progression is necessary to reduce the burden of this condition in the United States.

MATERIALS AND METHODS

We considered challenges to continuing the predominantly lower urinary tract dysfunction centric approach that has dominated previous research of lower urinary tract symptoms.

RESULTS

We developed a new, comprehensive framework for urology research that includes a broader set of potential factors contributing to lower urinary tract symptoms. This framework aims to broaden research to consider a comprehensive set of potential contributing factors and to engage a broad range of researchers in the investigation of as many extra-lower urinary tract factors as possible, with the goal of improving clinical care and prevention.

CONCLUSIONS

We propose a new framework for future urology research, which should help to reduce the medical and economic burden of lower urinary tract symptoms in the United States population.