Impulsivity in binge eating disorder: food cues elicit increased reward responses and disinhibition

Attention to food stimuli in binge eating disorder: Electrophysiological evidence

Attentional biases towards food play an important role in the pathology of binge eating disorder (BED). Later stage electrophysiological potentials (P300, late positive potential) present promising markers of motivated attention with high temporal, albeit low spatial resolution. Complementing this, the N2pc is an earlier-latency component providing the possibility of more directly analyzing visuospatial attention. Therefore, we tested a group with BED (N = 60), as well as an overweight (OW; N = 28) and normal weight (NW; N = 30) group without BED in a Go/No-Go paradigm using food and nonfood distractor images. Only the OW group in exclusively the Go trials displayed a stronger spatial attention allocation towards nonfood distractors as evidenced by an increased N2pc amplitude. In the P300's time window, the OW group displayed no attentional bias towards food and the NW group only did so in the absence of a target. Solely the BED group allocated more motivated attention towards food distractors both in Go and No-Go trials. In the following late positive potential (LPP), the OW group exhibited a general attentional bias towards food distractors, while the BED group only did so in the absence of a target. These results are discussed in light of the incentive sensitization theory and a potential early attentional suppression of potent distractors.

The Role of Attention in Placebo and Nocebo Effects

BACKGROUND

Although some existing models propose that attention may be crucially implicated in placebo/nocebo effects, empirical research on this aspect remains limited and scattered.

PURPOSE

This systematic review aims to provide an inclusive overview of studies that have either directly manipulated or assessed attention within the context of placebo and nocebo procedures so to gain a synthetized picture of the role of this variable in placebo/nocebo effects. Importantly, only studies in which attention represented a mechanism or mediator of the placebo/nocebo response, and not a primary outcome, were included.

METHODS

A systematic search was conducted across multiple databases, including PubMed, Scopus, PsycINFO, Web of Science, and Embase, to identify peer-reviewed studies. These studies were subjected to methodological evaluation and eligibility criteria for inclusion.

RESULTS

We identified and classified 12 studies into three categories based on their focus: (i) those that directly assessed attention, (ii) those that directly manipulated participants' attention, and (iii) those that combined both a direct manipulation and assessment of attention. In all selected studies attention acted as a mechanism or mediator of the placebo/nocebo response, and was not considered a primary outcome of the placebo/nocebo manipulation.

CONCLUSIONS

The synthesis of the included studies reveals that the role of attention in placebo and nocebo effects is still a topic of debate, marked by variations in how attention is conceptualized and measured. Results suggest that attention has significant clinical implications, particularly in optimizing therapeutic efficacy by directing patients' focus toward signs of healing and away from indicators of illness or distress. To advance our understanding, future research should explore these attentional mechanisms, in conjunction with neurophysiological correlates.

Neural Responses to Auditory Food Stimuli Following Cognitive Behavioral Therapy for Binge-Eating Disorder

OBJECTIVE

Adults with binge-eating disorder (BED), compared with those without BED, demonstrate higher blood-oxygen-level-dependent (BOLD) response to food cues in reward-related regions of the brain. It is not known whether cognitive behavioral therapy (CBT) can reverse this reward system hyperactivation. This randomized controlled trial (RCT) assessed changes in BOLD response to binge-eating cues following CBT versus wait-list control (WLC).

METHOD

Females with BED (N = 40) were randomized to CBT or WLC. Participants completed assessments at baseline and 16 weeks including measures of eating and appetite and functional magnetic resonance imaging (fMRI) to measure BOLD response while listening to personalized scripts of binge-eating and neutral-relaxing cues. Data were analyzed using general linear models with mixed effects.

RESULTS

Overall retention rate was 87.5%. CBT achieved significantly greater reductions in binge-eating episodes than WLC (mean ± standard error decline of 14.6 ± 2.7 vs. 5.7 ± 2.8 episodes in the past 28 days, respectively; p = 0.03). CBT and WLC did not differ significantly in changes in neural responses to binge-eating stimuli during the fMRI sessions. Compared with WLC, CBT had significantly greater improvements in reward-based eating drive, disinhibition, and hunger as assessed by questionnaires (ps < 0.05).

DISCUSSION

CBT was effective in reducing binge eating, but, contrary to our hypothesis, CBT did not improve BOLD response to auditory binge-eating stimuli in reward regions of the brain. Further studies are needed to assess mechanisms underlying improvements with CBT for BED.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT03604172.

Oculomotor behaviors in youth with an eating disorder: findings from a video-based eye tracking task

BACKGROUND

The oculomotor circuit spans many cortical and subcortical areas that have been implicated in psychiatric disease. This, combined with previous findings, suggests that eye tracking may be a useful method to investigate eating disorders. Therefore, this study aimed to assess oculomotor behaviors in youth with and without an eating disorder.

METHODS

Female youth with and without an eating disorder completed a structured task involving randomly interleaved pro-saccade (toward at a stimulus) and anti-saccade (away from stimulus) trials with video-based eye tracking. Differences in saccades (rapid eye movements between two points), eye blinks and pupil were examined.

RESULTS

Youth with an eating disorder (n = 65, Mage = 17.16 ± 3.5 years) were compared to healthy controls (HC; n = 65, Mage = 17.88 ± 4.3 years). The eating disorder group was composed of individuals with anorexia nervosa (n = 49), bulimia nervosa (n = 7) and other specified feeding or eating disorder (n = 9). The eating disorder group was further divided into two subgroups: individuals with a restrictive spectrum eating disorder (ED-R; n = 43) or a bulimic spectrum eating disorder (ED-BP; n = 22). In pro-saccade trials, the eating disorder group made significantly more fixation breaks than HCs (F(1,128) = 5.33, p = 0.023). The ED-BP group made the most anticipatory pro-saccades, followed by ED-R, then HCs (F(2,127) = 3.38, p = 0.037). Groups did not differ on rate of correct express or regular latency pro-saccades. In anti-saccade trials, groups only significantly differed on percentage of direction errors corrected (F(2, 127) = 4.554, p = 0.012). The eating disorder group had a significantly smaller baseline pupil size (F(2,127) = 3.60, p = 0.030) and slower pro-saccade dilation velocity (F(2,127) = 3.30, p = 0.040) compared to HCs. The ED-R group had the lowest blink probability during the intertrial interval (ITI), followed by ED-BP, with HCs having the highest ITI blink probability (F(2,125) = 3.63, p = 0.029).

CONCLUSIONS

These results suggest that youth with an eating disorder may have different oculomotor behaviors during a structured eye tracking task. The oculomotor behavioral differences observed in this study presents an important step towards identifying neurobiological and cognitive contributions towards eating disorders.

Behaviourally assessed negative urgency is uniquely associated with binge-eating frequency

OBJECTIVE

Binge eating appears to be associated with impulsivity, especially in response to negative affect (i.e., negative urgency). However, negative urgency is typically assessed via self-report, which captures only some aspects of urgency and may be subject to bias. Few studies have examined impulsivity following experimental manipulations of affect in binge-eating samples.

METHOD

In the present study, individuals who engage in regular binge eating completed a behavioural impulsivity (go/no-go) task with high- and low-calorie food stimuli, once following negative affect induction and once following neutral affect induction.

RESULTS

Greater behavioural impulsivity to high-calorie food cues while in a negative (and not a neutral) affective state was associated with more frequent binge-eating behaviour. Further, this behavioural measure of negative urgency uniquely accounted for variance in binge-eating frequency when controlling for self-reported negative urgency, suggesting that behavioural measures may be a useful complement to self-report measures.

DISCUSSION

These findings provide novel and compelling evidence for the relationship between negative urgency and binge eating, highlighting negative urgency as a potentially important target for intervention.

The role of irrational beliefs in the relationship between attention deficit hyperactivity disorder (ADHD) symptoms and disordered eating in two general student samples

Attention deficit hyperactivity disorder (ADHD) symptoms are associated with disordered eating and negative mood. The purpose of this study was to examine whether irrational beliefs mediate this relationship along with previously reported mediators such as depression and impulsivity. Irrational beliefs trigger negative automatic thoughts which are believed, in cognitive behavior therapies, to be a source of psychopathology. Challenges brought about by symptoms of ADHD may lead to habitual emotion-eliciting thought patterns which, in turn, could lead to negative mood and disordered eating. Undergraduate students (N = 127) completed online questionnaires assessing ADHD symptoms and disordered eating and several potential mediators including irrational beliefs, depression, impulsivity, interoceptive accuracy, and reward responsiveness. The results, which were replicated in a second study (N = 254), indicated that irrational beliefs and depression mediated the relationship between ADHD symptoms and disordered eating. In the second study, impulsivity due to negative urgency was also a mediator. These findings support the theory that the symptoms of ADHD lead to enhancement of irrational beliefs, depression, and negative urgency which are linked to disordered eating.

Practice makes perfect: Restrained eaters' heightened control for food images

OBJECTIVE

Restrained eaters (RE) show behaviourally unregulated food intake, which is often explained by a deficit in inhibitory control. Despite evidence for general inhibitory deficits in RE, it remains unclear how the variety of (food) cues in our environment can influence cognitive control.

METHOD

In this re-analysis, we explored the inhibitory capacity of RE and unrestrained eaters (URE) on a stop-signal task with modal (pictures) and amodal (word) food and non-food stimuli.

RESULTS

Although we did not find the expected inhibitory deficits in RE compared to URE, we found a significant Group × Modality × Stimulus Type interaction. This indicated that RE have relatively good inhibitory control for food, compared to non-food modal cues, and that this relationship is reversed for amodal cues.

CONCLUSIONS

Hence, we showed differential processing of information based on food-specificity and presentation format in RE. The format of food cues is thus an important new avenue to understand how the food environment impedes those struggling with regulating their eating behaviour.

A scoping review of emotion regulation and inhibition in emotional eating and binge-eating disorder: what about a continuum?

BACKGROUND

Emotional eating is defined as a nonpathological eating behavior, whereas binge-eating disorder (BED) is defined as a pathological eating behavior. While different, both share some striking similarities, such as deficits in emotion regulation and inhibition. Previous research has suggested the existence of an "eating continuum" that might reflect the increased severity of overeating behaviors, that is, from nonpathological overeating to BED. The main aims of this scoping review were to explore in the literature the idea of a continuum between emotional eating and BED and to observe whether deficits in emotion regulation and inhibition follow this continuum in terms of severity. The other aims were to hopefully clarify the ill-defined concept of overeating, to question the potential role of positive emotions and to identify potential knowledge gaps.

METHOD

A systematic scoping review was conducted following the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) guidelines. Two databases (PubMed/Medline and PsycINFO) were examined in complete accordance with the beforehand sharply defined eligibility and exclusion criteria. The main criteria included adults (≥ 18) with emotional eating, BED or overeating and emotion regulation and inhibition as exposure criteria.

RESULTS

Thirty-two studies were included in this scoping review. If the results showed a link between emotional eating and BED, with the presence of inhibition and emotion regulation deficits in both eating behaviors, no mention of a continuum between emotional eating and BED was found.

CONCLUSION

In the absence of research directly comparing emotional eating and BED in the same studies and testing the potential increase in severity of emotion regulation and inhibition deficits along this continuum, there is currently no certainty that a continuum exists between emotional eating and BED. In the end, the idea of a continuum in terms of increased severity of overeating and in terms of emotion regulation and inhibition deficits between emotional eating and BED appears to be a gap in knowledge in the literature. This scoping review highlights the need for further research to identify knowledge gaps.

Sex differences in regional gray matter density in pre-adolescent binge eating disorder: a voxel-based morphometry study

BACKGROUND

Binge eating disorder (BED) is a pernicious psychiatric disorder which is linked with broad medical and psychiatric morbidity, and obesity. While BED may be characterized by altered cortical morphometry, no evidence to date examined possible sex-differences in regional gray matter characteristics among those with BED. This is especially important to consider in children, where BED symptoms often emerge coincident with rapid gray matter maturation.

METHODS

Pre-adolescent, 9-10-year old boys (N = 38) and girls (N = 33) with BED were extracted from the 3.0 baseline (Year 0) release of the Adolescent Brain Cognitive Development Study. We investigated sex differences in gray matter density (GMD) via voxel-based morphometry. Control sex differences were also assessed in age and body mass index and developmentally matched control children (boys N = 36; girls N = 38). Among children with BED, we additionally assessed the association between dorsolateral prefrontal (dlPFC) GMD and parent-reported behavioral approach and inhibition tendencies.

RESULTS

Girls with BED uniquely demonstrate diffuse clusters of greater GMD (p < 0.05, Threshold Free Cluster Enhancement corrected) in the (i) left dlPFC (p = 0.003), (ii) bilateral dmPFC (p = 0.004), (iii) bilateral primary motor and somatosensory cortex (p = 0.0003) and (iv) bilateral precuneus (p = 0.007). Brain-behavioral associations suggest a unique negative correlation between GMD in the left dlPFC and behavioral approach tendencies among girls with BED.

CONCLUSIONS

Early-onset BED may be characterized by regional sex differences in terms of its underlying gray matter morphometry.

Abnormal sense of agency in eating disorders

The feeling of controlling one's own actions and, through them, impacting the external environment (i.e. Sense of Agency-SoA) can be relevant in the eating disorders (EDs) symptomatology. Yet, it has been poorly investigated. This study aims to implicitly assess SoA exploiting the Sensory Attenuation paradigm in two groups of EDs patients (Anorexia Nervosa Restrictive and Anorexia Nervosa Binge-Purging or Bulimia Nervosa) compared to a control group. We find that controls perceive self-generated stimuli as less intense than other-generated ones showing the classic pattern of sensory attenuation. By contrast, EDs patients show the opposite pattern, with self-generated perceived as more intense than other-generated stimuli. This result indicates an alteration of the implicit component of the feeling of control in EDs patients, thus suggesting a potential implication of these results for the clinical practice and the treatment of EDs symptomatology.

Attentional bias for high-calorie food cues by the level of hunger and satiety in individuals with binge eating behaviors

Introduction

The abnormal hyperreactivity to food cues in individuals with binge eating behaviors could be regulated by hedonic or reward-based system, overriding the homeostatic system. The aim of the present study was to investigate whether attentional bias for food cues is affected by the level of hunger, maintaining the normal homeostatic system in individuals with binge eating behaviors.

Methods

A total of 116 female participants were recruited and divided into four groups: hungry-binge eating group (BE) (n = 29), satiated BE (n = 29), hungry-control (n = 29), satiated control (n = 29). While participants completed a free-viewing task on high or low-calorie food cues, visual attentional processes were recorded using an eye tracker.

Results

The results revealed that BE group showed longer initial fixation duration toward high-calorie food cues in both hunger and satiety condition in the early stage, whereas the control group showed longer initial fixation duration toward high-calorie food cues only in hunger conditions. Moreover, in the late stage, the BE group stared more at the high-calorie food cue, compared to control group regardless of hunger and satiety.

Discussion

The findings suggest that automatic attentional bias for food cues in individuals with binge eating behaviors occurred without purpose or awareness is not affected by the homeostatic system, while strategic attention is focused on high-calorie food. Therefore, the attentional processing of food cues in binge eating group is regulated by hedonic system rather than homeostatic system, leading to vulnerability to binge eating.

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.

Aberrant functional connectivity between reward and inhibitory control networks in pre-adolescent binge eating disorder

BACKGROUND

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

58 pre-adolescent children (aged 9-10-years) with BED (mBMI = 25.05; s.d. = 5.40) and 66 age, BMI and developmentally matched control children (mBMI = 25.78; s.d. = 0.33) were extracted from the 3.0 baseline (Year 0) release of the Adolescent Brain Cognitive Development (ABCD) Study. We investigated group differences in resting-state functional MRI functional connectivity (FC) within and between reward and inhibitory control networks. A seed-based approach was employed to assess nodes in the reward [orbitofrontal cortex (OFC), nucleus accumbens, amygdala] and inhibitory control [dorsolateral prefrontal cortex, anterior cingulate cortex (ACC)] networks via hypothesis-driven seed-to-seed analyses, and secondary seed-to-voxel analyses.

RESULTS

Findings revealed reduced FC between the dlPFC and amygdala, and between the ACC and OFC in pre-adolescent children with BED, relative to controls. These findings indicating aberrant connectivity between nodes of inhibitory control and reward networks were corroborated by the whole-brain FC analyses.

CONCLUSIONS

Early-onset BED may be characterized by diffuse abnormalities in the functional synergy between reward and cognitive control networks, without perturbations within reward and inhibitory control networks, respectively. The decreased capacity to regulate a reward-driven pursuit of hedonic foods, which is characteristic of BED, may in part, rest on this dysconnectivity between reward and inhibitory control networks.

Behavioural biases in the interaction with food objects in virtual reality and its clinical implication for binge eating disorder

Cognitive processes play a central role in the development, maintenance and remission in mental disorders, like in Binge Eating Disorder (BED). Insights into cognitive mechanisms reflected by embodied interaction with food and its connections to clinically relevant psychopathology offer new possibilities for translational diagnostics and interventions. We longitudinally investigated the manual interaction with food in a virtual reality (VR) in 31 patients with BED. Patients were assessed at baseline before participating in a randomized-controlled trial (RCT) investigating a computer-based inhibitory control training programme enhanced by transcranial direct current stimulation (tDCS) and at a 6-week follow-up. At both assessments, an experimental VR paradigm was conducted and patients were characterized concerning eating disorder psychopathology, eating behaviour, general impulsivity and food craving. In the experimental task, one of two simultaneously presented objects (food vs. office tools) had to be collected. Food was recognized faster than office tools and subsequent approach behaviour was initiated faster, whereas thereafter, food was collected slower than office tools. Exploratory, we could not find a modulatory effect of applied tDCS on the interaction with food. No relationship between behavioural biases and sample characterizations could be detected. Two different stages in the manual interaction with food were found: a faster first stage that comprises recognition and movement initiation and a slower second stage that comprises controlled handling and may reflect aversive motivational processes. As the behavioural patterns do not change with an ameliorated BED-psychopathology at the second assessment, the task seems insensitive in detecting translational interconnections between behavioural biases and BED-characteristics.Level of evidence: Level I, experimental study.

Food-related reward sensitivity across the spectrum of body weight and impulsive eating: Pilot findings from a multi-method approach

Overweight with and without comorbid binge-eating disorder (BED) has been associated with increased reward sensitivity, though evidence is heterogeneous. To disentangle this heterogeneity and gain insights into mechanisms of impaired reward processing, this study applied multi-method neuro-behavioural techniques. Reward sensitivity was investigated in N = 49 participants allocated to three subgroups: overweight individuals with BED (BED+, n = 17), overweight individuals without BED (BED-, n = 15), and normal-weight controls (NWC, n = 17). Applying a free exploration paradigm (food vs. non-food stimuli), eye tracking and electroencephalographic data were gathered. A valid cue before stimulus onset indicated the position of food, and the end points analysed after the cue and stimulus onset were attentional approach, attention allocation, and conflict processing (e.g., conflict between looking at the potentially rewarding food stimulus or not). The effect of negative mood was tested using mood induction. The study's main hypothesis was that individuals with overweight, particularly under negative mood, would have increased food-related reward sensitivity. All participants showed increased food-specific attentional approach (p < .001). BED + allocated more attention to food stimuli than non-food stimuli compared to the healthy control (p = .045). For individuals with overweight but without BED (BED-), results indicate that conflict processing might be prolonged after the stimulus onset (p = .011). No group-specific effect of negative mood was found. Preliminary results in overweight individuals with and without comorbid BED suggest that food stimuli are generally rewarding stimuli, but even more so for participants with binge eating psychopathology. Prolonged conflict processing during the confrontation with competing food and non-food stimuli was solely found in the BED- sample and might indicate a compensation mechanism. Replication is warranted. The multi-method approach seems to be promising to give indications for the development of psychotherapeutic treatment.

Is history of abuse predictive of eating disorders with binge-eating episodes through an effect mediated by impulsivity? A French longitudinal study

BACKGROUND

In recent years, many studies have explored the associations among impulsivity, history of abuse, the emergence of eating disorders with episodes of binge eating (EDBE) and their severity. Nevertheless, factors associated with successful clinical outcomes of EDBE are still unknown. Our study aimed to test the hypothesis that a history of abuse is associated with unsuccessful clinical outcomes of EDBE through an effect mediated by impulsivity.

METHODS

We assessed patients older than 15 years, 3 months with EDBE at inclusion and at 1 year. Recovery was defined as the absence of eating disorders at 1 year. A mediation analysis was performed by means of structural equation modelling.

RESULTS

We included 186 patients in our analyses (54% bulimia nervosa, 29% anorexia nervosa binge eating/purging type and 17% binge-eating disorder); 179 (96%) were female. One-third (n = 63) of patients reported a history of abuse, and recovery was observed for 20% of the sample (n = 38). Contrary to our assumption, a history of abuse was not associated with the absence of recovery of EDBE at 1 year. Factors unfavourable for achieving recovery were anxiety disorders (odds ratio [OR] 0.41), vomiting (OR 0.39), physical hyperactivity (OR 0.29), negative urgency and a lack of perseverance (OR 0.85 for both). Only positive urgency was positively associated with recovery (OR 1.25).

LIMITATIONS

We excluded 219 patients lost to the 1-year follow-up.

CONCLUSION

Our findings may help to deconstruct the empirical belief that traumatic events may interfere with the successful course of treatment for eating disorders. A high level of positive urgency may be associated with more receptivity to care.

Dynamic attentional bias for pictorial and textual food cues in the visual search paradigm

Previous studies have found that individuals have an attentional bias for food cues, which may be related to the energy level or the type of stimulus (e.g., pictorial or textual food cues) of the food cues. However, the available evidence is inconsistent, and there is no consensus about how the type of stimulus and food energy modulate food-related attentional bias. Searching for food is one of the most important daily behaviors. In this study, a modified visual search paradigm was used to explore the attentional bias for food cues, and eye movements were recorded. Food cues consisted of both food words and food pictures with different energy levels (i.e., high- and low-calorie foods). The results showed that there was an attentional avoidance in the early stage but a later-stage attentional approach for all food cues in the pictorial condition. This was especially true for high-calorie food pictures. Participants showed a later-stage conflicting attentional bias for foods with different energy levels in the textual condition. They showed an attentional approach to high-calorie food words but an attentional avoidance of low-calorie food words. These data show that food-related attentional bias varied along with different time courses, which was also modulated by the type of stimulus and food energy. These findings regarding dynamic attentional bias could be explained using the Goal Conflict Model of eating behavior.

Orbitofrontal cortex functional connectivity changes in patients with binge eating disorder and bulimia nervosa

We aimed to define the shared and unshared functional neurobiological underpinnings of binge eating disorder (BED) and bulimia nervosa (BN). These disorders both involve loss of control over binge eating, but differ based on purging behavior and body image distortion. BED and BN have also been found to show differences in brain activation patterns in reward sensitivity. We enrolled 13 and 12 drug-naive and medication-free women with BED and BN, respectively, and 22 age- and sex-matched healthy controls. We performed an orbitofrontal cortex (OFC)-seeded resting-state whole brain functional connectivity (FC) analysis among the groups. In this study, BED patients exhibited significantly higher impulsivity than controls, whereas the difference in impulsivity between BN and controls was not significant. Participants with BED and BN showed weaker FC between the left lateral OFC and the right precuneus than controls. In the BED only group, the FC strength between these regions was negatively correlated with self-reported impulsivity. In both BED and BN, FC between the left lateral OFC and the right dorsolateral prefrontal cortex was weaker than that in controls. In BED, FC between the left medial OFC and the right cerebellar lobule IV was stronger than that of other groups. Our current results suggest similarities and differences between BED and BN in OFC-seeded FC with respect to reward processing. In particular, FC of the OFC in BED patients showed a significant correlation with their high impulsivity, which may reflect a decline in executive control over binge eating.

Exploring Mindfulness and Mindful Eating and Visual Attention Towards Food Cues: Preliminary Findings

Continual exposure to energy dense foods is suggested to promote overeating and obesity. The aim of the present research was to explore whether or not mindfulness could reduce visual attention towards food cues. In two laboratory studies, participants with a normal weight range completed an eye-tracking paradigm, and their eye-movements were recorded. In study 1, participants were exposed to either mindfulness meditation or a control condition, and their eye-movements towards low energy density (LED) vs high energy density (HED) food cues were measured. In study 2, participants were assigned to a mindful eating condition using a Mindful Construal Diary (MCD) or a control condition, and their eye-movements towards LED or HED food vs. non-food cues were recorded. In study 1, participants in the mindfulness meditation condition had greater attention duration towards LED food cues, whilst those in the control condition exhibited greater attention duration towards HED food cues. In study 2, there were no significant differences in the maintenance of attentional biases towards food cues between the two conditions. Mindfulness meditation may be beneficial in increasing attention towards LED food cues. Future research should further explore the effect of mindfulness and mindful eating on visual attention towards food cues with people who suffer from excess weight or have obesity, and also within naturalistic settings.

Neural Correlates of Executive Functioning in Anorexia Nervosa and Obsessive-Compulsive Disorder

Anorexia nervosa (AN) and obsessive-compulsive disorder (OCD) are commonly reported to co-occur and present with overlapping symptomatology. Executive functioning difficulties have been implicated in both mental health conditions. However, studies directly comparing these functions in AN and OCD are extremely limited. This review provides a synthesis of behavioral and neuroimaging research examining executive functioning in AN and OCD to bridge this gap in knowledge. We outline the similarities and differences in behavioral and neuroimaging findings between AN and OCD, focusing on set shifting, working memory, response inhibition, and response monitoring. This review aims to facilitate understanding of transdiagnostic correlates of executive functioning and highlights important considerations for future research. We also discuss the importance of examining both behavioral and neural markers when studying transdiagnostic correlates of executive functions.

Regional gray matter abnormalities in pre-adolescent binge eating disorder: A voxel-based morphometry study

BACKGROUND

Binge eating disorder (BED) is a pernicious psychiatric disorder which is linked with an array of multisystemic organ morbidity, broad psychiatric morbidity, and obesity. Despite behavioral markers often developing in early childhood, the neurobiological markers of early-onset BED remain understudied, and developmental pathophysiology remains poorly understood.

METHODS

71 preadolescent children (aged 9-10-years) with BED and 74 age, BMI and developmentally matched control children were extracted from the 3.0 baseline (Year 0) release of the Adolescent Brain Cognitive Development (ABCD) Study. We investigated group differences in gray matter density (GMD) via voxel-based morphometry (VBM). We additionally performed region of interest analyses, assessing the association between GMD in nodes of the reward (orbitofrontal cortex; OFC) and inhibitory control (dorsolateral prefrontal cortex; dlPFC) networks, and parent-reported behavioral inhibition and approach tendencies.

RESULTS

Diffuse elevations in cortical GMD were noted in those with BED, which spanned prefrontal, parietal, and temporal regions. No areas of reduced GMD were noted in those with BED. No alterations in subcortical GMD were noted. Brain-behavioral associations suggest a distinct and negative relationship between GMD in the OFC and dlPFC, respectively, and self-reported markers of hedonic behavioral approach tendencies.

CONCLUSIONS

Early-onset BED may be characterized by diffuse morphological abnormalities in gray matter density, suggesting alterations in cortical architecture which may reflect decreased synaptic pruning and arborization, or decreased myelinated fibers and therefore inter-regional afferents.

Sadness-associated eating styles and visual food cue reactivity: An eye-tracking investigation

BACKGROUND

Emotional eating has been associated with biases of attention and memory for visual food cues. This eye-tracking study investigated whether the tendency to overeat in response to sadness is associated with the inspection and recall of visual food cues.

METHOD

Participants (n = 115, mean age = 26 years, 70 females, 45 males) viewed images depicting food and non-food. We compared gaze duration, 'hyperscanning' parameters (fixation duration, saccadic angle, scan path length), and recall performance between different image categories (high-calorie, low-calorie food, non-food) and groups with different sadness-associated eating styles (increased, decreased, unchanged food consumption during states of sadness).

RESULTS

The group with sadness-related overeating reported a higher body mass index than the other groups, but neither displayed a visual attention bias nor memory bias for food cues. We observed a prolonged gaze duration for low-calorie food cues, which were rated as more appetizing than high-calorie cues. All participants recalled more food cues (low- and high-calorie) than non-food cues independent of gaze duration.

CONCLUSION

This study expanded previous research designs by groups that decrease vs. increase the amount eaten when feeling sad, and food/non-food images that were carefully matched for visual properties. Based on this approach, we were not able to show that self-disclosed sadness eating is associated with visual/memory biases for food images.

Ameliorating cognitive control in patients with binge eating disorder by electrical brain stimulation: study protocol of the randomized controlled ACCElect pilot trial

BACKGROUND

The current first-line treatment for binge eating disorder (BED), which is psychotherapy, is moderately effective in terms of abstinence from binge-eating. Neurobiological evidence suggests that people affected by BED show difficulties along the spectrum of impulsivity, including inhibitory control impairments and highlights the potential of novel treatment approaches directly targeting inhibitory control, including cognitive training approaches and non-invasive brain stimulation.

METHODS

ACCElect is a prospective, randomized controlled pilot trial investigating a novel, food-related inhibitory control training combined with transcranial direct current stimulation (tDCS). 40 patients with BED will be randomly assigned to receive the training either combined with verum or with sham stimulation (control condition). The inhibitory control training is based on principles of the antisaccade paradigm and comprises six training sessions over two weeks. Core aims are the investigation of feasibility and clinically relevant effects of a tDCS-enhanced inhibitory control training in BED patients and the establishment of a data basis for a larger efficacy trial. The primary clinical endpoint is binge-eating (BE) frequency in terms of changes in BE episodes four weeks after treatment termination as compared to baseline. Key secondary outcomes comprise ED pathology and general psychopathology, inhibitory control capacities, quality of life as well as acceptability and satisfaction with the intervention.

DISCUSSION

The results of the present trial will contribute to the development of novel neurobiologically informed treatment approaches for patients suffering from BED. Trial registration The ACCElect trial was prospectively registered on October 1, 2020, under the registration number NCT04572087 at ClinicalTrials.gov ( https://clinicaltrials.gov/ct2/show/NCT04572087 ).

Modulating eating behavior with transcranial direct current stimulation (tDCS): A systematic literature review on the impact of eating behavior traits

Transcranial direct current stimulation (tDCS) is becoming an increasingly popular technique for altering eating behaviors. Recent research suggests a possible eating behavior trait-dependent effect of tDCS. However, studies recruit participant populations with heterogeneous trait characteristics, including "healthy" individuals who do not present with eating behavior traits suggesting susceptibility to overconsumption. The present review considers the effects of tDCS across eating-related measures and explores whether a trait-dependent effect is evident across the literature. A literature search identified 28 articles using sham-controlled tDCS to modify eating-related measures. Random effects meta-analyses were performed, with subgroup analyses to identify differences between "healthy" and trait groups. Trivial overall effects (g = -0.12 to 0.09) of active versus sham tDCS were found. Subgroup analyses showed a more consistent effect for trait groups, with small and moderate effect size (g = -1.03 to 0.60), suggesting tDCS is dependent on participants' eating behavior traits. Larger effect sizes were found for those displaying traits associated with study outcomes (e.g., heightened food cravings). "Healthy" individuals appear to be unresponsive to stimulation. Based on this meta data, future work should recruit those with eating behavior trait susceptibilities to overconsumption, focusing on those who present with traits associated with the outcome of interest.

Eating disorder-specific rumination moderates the association between attentional bias to high-calorie foods and eating disorder symptoms: Evidence from a reliable free-viewing eye-tracking task

Cognitive theories of eating disorders implicate Attentional Bias (AB) towards food-related information in the development and maintenance of eating disorders. Empirical evidence for this proposal, however, has been inconsistent, and the measures used to examine AB to food-related stimuli typically showed poor reliability. The aim of the current study was twofold. Firstly, we aimed to examine the psychometric properties of a newly devised eye-tracking task for the assessment of AB in the context of eating disorders. Secondly, we examined the role of Eating Disorder-specific (ED-specific) rumination as a potential moderator of the association between attentional bias to food images and eating disorder symptoms. One hundred and three female students were recruited and completed an eye-tracking task comprising 21 matrices that each contained 8 low-calorie and 8 high-calorie food images. Each matrix was presented for 6 s. First fixation location, first fixation latency, and total dwell time were assessed for low and high-calorie food images and the dwell-time based AB measure showed good reliability based on Cronbach's alpha, McDonald's Omega, and split-half method. In addition, the results revealed that the ED-specific rumination plays the hypothesized moderating role. Specifically, while participants with high levels of ED-specific rumination exhibited a positive association between AB to high-calorie foods and eating disorder symptoms, this association was not present among participants with lower levels of ED-specific rumination. The employed free-viewing task seems a reliable measure of AB to food-related stimuli, and the moderation analysis emphasizes the critical role of ED-specific rumination for eating disorder symptoms. Implications, limitations, and directions for future research are discussed.

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.

Dynamic changes in the food-cue processing of obese adolescents: A controlled eye-tracking study from a dual-system perspective

Adolescent obesity is a growing global health problem. Studies have demonstrated that exposure to food cues plays a role in both the development and the persistence of obesity. Understanding how visual attention changes dynamically in response to food cues may explain how they contribute to obesity. The primary aims were to evaluate attentional bias for food cues and conduct a time-course analysis of obese adolescents' food-cue processing. We also investigated the roles of inhibition, cognitive flexibility, and eating styles in their visual attention to food stimuli. A total of 60 age- and gender-matched 12-16-year-olds (n = 30, obese group; n = 30, control group; M = 13.9 years, SD = 1.26) were included in this study's sample. The participants viewed a series of high-calorie and low-calorie food images along with nonfood images in the free exploration paradigm during eye-tracking. Time-course analysis of the proportion of fixations on images of food and high-calorie foods determined that the attentional processing of the two groups differed, especially in later stages. The obese group had higher Stroop Interference and Trail Making Test-B scores than the control group, but these executive functions' scores did not affect their proportions of fixations on food and high-calorie food images over time. Higher Perceptual Reasoning Index scores led to a decrease in the proportions of fixations on high-calorie food images over time in the obese group, and this was particularly noticeable after about 4000 ms. This study found that time-course analysis of visual attention to food cues allows us to understand how it changes dynamically over larger time intervals. Future studies should provide knowledge about maintained attention for food cues and their relationship with top-down factors in obese adolescents.

App-based food-specific inhibitory control training as an adjunct to treatment as usual in binge-type eating disorders: A feasibility trial

Current treatments for binge eating disorder (BED) and bulimia nervosa (BN) only show moderate efficacy, warranting the need for novel interventions. Impairments in food-related inhibitory control contribute to BED/BN and could be targeted by food-specific inhibitory control training (ICT). The aim of this study was to establish the feasibility and acceptability of augmenting treatment for individuals with BN/BED with an ICT app (FoodT), which targets motor inhibition to food stimuli using a go/no-go paradigm. Eighty patients with BED/BN receiving psychological and/or pharmacological treatment were randomly allocated to a treatment-as-usual group (TAU; n = 40) or TAU augmented with the 5-min FoodT app daily (n = 40) for 4 weeks. This mixed-methods study assessed feasibility outcomes, effect sizes of clinical change, and acceptability using self-report measures. Pre-registered cut-offs for recruitment, retention, and adherence were met, with 100% of the targeted sample size (n = 80) recruited within 12 months, 85% of participants retained at 4 weeks, and 80% of the FoodT + TAU group completing ≤8 sessions. The reduction in binge eating did not differ between groups. However, moderate reductions in secondary outcomes (eating disorder psychopathology: SES = -0.57, 95% CI [-1.12, -0.03]; valuation of high energy-dense foods: SES = -0.61, 95% CI [-0.87, -0.05]) were found in the FoodT group compared to TAU. Furthermore, small greater reductions in food addiction (SES = -0.46, 95% CI [-1.14, 0.22]) and lack of premeditation (SES = -0.42, 95% CI [-0.77, -0.07]) were found in the FoodT group when compared to TAU. The focus groups revealed acceptability of FoodT. Participants discussed personal barriers (e.g. distractions) and suggested changes to the app (e.g. adding a meditation exercise). Augmenting treatment for BED/BN with a food-specific ICT app is feasible, acceptable, and may reduce clinical symptomatology with high reach and wide dissemination.

(Mouse cursor)-Tracking food decisions in binge eating disorder reveals preference for high-energy foods and a role of BMI

Binge Eating Disorder (BED) has been associated with deficits in cognitive control and decision-making. Yet, no study has yet investigated the characteristics of food choice and the involved choice conflict in this disorder. In the present study individuals with BED (N = 22) and without BED (N = 61), with a body mass index (BMI) between 21 and 44 completed 153 binary food decisions among foods varying in palatability and energy density. To assess conflict during choice we recorded computer mouse paths and reaction times. Subsequently, participants rated all foods on liking and energy content. Finally, participants completed a bogus taste test with the same foods to measure actual consumption. Predictors were modelled continuously using Bayesian mixed-effects modelling. Individuals with BED liked foods with higher energy content more and chose them more often in the choice task. Yet, actual consumption in the taste test did not differ between groups, neither regarding total consumption, nor of foods with higher energy. Mouse cursor-tracking revealed that control participants with higher BMIs showed more choice conflict than those with lower BMIs. This pattern was reversed in those with BED. The high-energy preference in ratings and food choice represent the first evidence in a controlled laboratory context for disorder-congruent food choice in BED. The fact that this was not reflected in actual consumption might have methodological implications for measuring laboratory eating behaviour. Mouse cursor-tracking gave further insights into choice processes and showed a less conflicted food choice in those with BED with higher BMI compared to those with lower BMI.

Cognitive function in binge eating disorder and food addiction: A systematic review and three-level meta-analysis

BACKGROUND

An extensive body of recent research has focused on the contribution of cognitive functioning to eating behaviors. In binge eating disorder (BED) and food addiction (FA), the extent of cognitive impairment is still unclear. This study aimed to characterize, among those with BED and FA, neurocognitive functions using performances based on neuropsychological tasks in the context of neutral stimuli in adults.

METHOD

MEDLINE, Embase, PsycINFO, Cochrane Database of Systematic Reviews, CINAHL and gray literature (ProQuest and OpenGrey) were used to identify studies that reported neurocognitive assessments in BED or FA up to December 2019. A three-level meta-analysis was conducted.

RESULTS

A significant overall effect was found for global cognitive impairments, suggesting that individuals with BED or FA have poorer performances when completing cognitive tasks. Analyses for specific cognitive domains revealed that individuals with BED showed poorer performances at tasks assessing cognitive flexibility, inhibitory control, attention and planning. Analyses regarding FA were inconclusive due to a lack of studies. Thus, the results were described qualitatively.

CONCLUSION

Our meta-analysis highlighted the cognitive weaknesses that seem to come with BED and the necessity to integrate them in the assessment and treatment of this condition. It also stressed the lack of quality studies surrounding the cognitive features of FA.

A Pilot Event-Related Potentials Study on Mechanisms Underlying a tDCS-Enhanced Food-Specific Response Inhibition Task for Patients With Binge Eating Disorder

Behavioural studies demonstrate alterations in cognitive functioning, particularly impaired response inhibition and increased attentional bias towards food in binge eating disorder (BED). This pilot study aimed to investigate the neurophysiological processing of a food-specific inhibition training combined with anodal transcranial direct current stimulation (tDCS) of the right dorsolateral prefrontal cortex (DLPFC) in 16 patients with BED (mean age = 38.6, mean BMI = 33.7 kg/m²). Patients performed a food-specific antisaccade task at baseline (T0) and in a cross-over design with verum vs. sham stimulation at T1 and T2. We investigated (i) event-related potentials (ERPs; N2, ERN and P3 amplitudes) while executing the task at baseline, (ii) whether baseline ERPs would predict task performance at T1 and T2 and (iii) associations between ERPs, eating disorder pathology and impulsivity at baseline. The mean amplitude of N2 was less pronounced in erroneous saccades (ES) than correct saccades (CS), whereas ERN and P3 mean amplitudes were more pronounced in ES. Moreover, the P3 mean amplitude of ES predicted the percentage of ES at both follow up-measurements irrespective of the applied stimulation (sham vs. verum). N2 in trials with correct saccades were negatively correlated with nonplanning trait impulsivity, while P3 in erroneous antisaccade trials was negatively correlated with food-related impulsivity. Overall, the findings of reduced ERN, enhanced P3 and N2 amplitude might be interpreted as difficulties in response inhibition towards food in individuals with BED. In particular, P3 predicts task outcome at follow-up and might represent a potential marker for inhibitory control processes.

Suicidality risk among adults with binge-eating disorder

OBJECTIVE

To estimate relative suicidality risk associated with binge-eating disorder (BED).

METHODS

Retrospective study of patients identified as having BED (N = 1042) and a matched general population cohort (N = 10,420) from the Optum electronic health record database between January 2009 and September 2015. Patients had ≥1 outpatient encounter with a provider who recognized BED during the 12-month baseline preceding entry date. Incidence and relative risk of suicidality were assessed.

RESULTS

Incidence per 1000 person-years (95% CI) of suicidal ideation and suicide attempts, respectively, was 31.1 (23.1, 41.0) and 12.7 (7.9, 19.4) in the BED cohort and 5.8 (4.7, 7.1) and 1.4 (0.9, 2.2) in the comparator cohort. Risk of suicidal ideation and suicide attempts was greater in the BED cohort (HR [95% CIs], 6.43 [4.42, 9.37]) than in the comparator cohort (HR [95% CI], 9.47 [4.99, 17.98]) during follow-up. After adjusting for psychiatric comorbidities, associations of suicidal ideation and suicide attempts with BED remained elevated in patients with BED having histories of suicidality.

CONCLUSIONS

Findings suggest that history of suicidality may result in an increased risk of suicidal ideation and suicide attempts in patients with BED relative to the general population. Psychiatric comorbidity burden may explain the elevated risk of these conditions in BED.

THE RELATIVE REINFORCING VALUE OF SNACK FOOD IS A SIGNIFICANT PREDICTOR OF FAT LOSS IN WOMEN WITH OVERWEIGHT OR OBESITY

Reinforcing Relative Value (RRV) of food and impulsivity are associated with energy intake and obesity. The study investigated the degree to which changes in RRV and impulsivity independently or interactively predict change in body weight and composition in women with overweight or obesity engaged in either a fast or in a slow weight loss programs. Body weight, body composition, Impulsivity (Barratt Impulsiveness Scale), RRV snack (computerized Behavioural Choice Task) were measured at baseline and post-intervention in 30 women with obesity undergoing either slow (n= 14 -500 kcal/day, 20 weeks) or fast n=16 (-1000kcal/day, 10 weeks) weight reduction. No group*time effects were noted on body composition, impulsivity or RRV, so participants from both groups were pooled for analysis. Multiple regression analyses indicated that none of the impulsivity variables predicted weight- or fat mass (FM) loss. However, Δ RRV snack predicted ΔFM (r=0.40, P=0.046), whereby greater increases in RRV snack were associated with less FM loss. Results indicate that different rates of weight loss do not differentially affect RRV snack or impulsivity traits. However, changes in RRV snack predicted FM loss, suggesting that dietary interventions that either mitigate increases or foster reductions in the RRV snack may yield greater reductions in adiposity. Trial Registration clinicaltrials.gov identifier: NCT04866875 NOVELTY POINTS • No differences in RRV of food were noted between fast and slow weight loss • Weight loss from combined fast and slow groups led to a moderate-sized reduction in the total impulsivity • Greater diet-induced increases in RRV snack was associated with less body fat-loss.

Impulsivity and compulsivity in binge eating disorder: A systematic review of behavioral studies

BACKGROUND

Binge eating disorder (BED) often includes impulsive and compulsive behaviors related to eating behavior and food. Impulsivity and compulsivity generally may contribute to the etiology and maintenance of multiple psychiatric disorders including BED. This review aimed to identify and synthesize available behavioral studies of impulsivity and compulsivity among individuals with BED.

METHOD

A systematic search was performed focusing on BED and specific facets of impulsivity (rapid response and choice) and compulsivity (set-shifting, cognitive flexibility, and/or habit learning). All case-control studies comparing adults with either full-threshold or subthreshold BED to individuals with normal weight, overweight/obesity, or other eating disorders (e.g., bulimia nervosa) were included.

RESULTS

Thirty-two studies representing 29 unique samples met inclusion criteria. Increased choice impulsivity was observed among individuals with BED relative to individuals with normal weight. There were mixed findings and/or a lack of available evidence regarding rapid response impulsivity and compulsivity. The presence of between-group differences was not dependent on sample characteristics (e.g., full or sub threshold BED diagnosis, or treatment-seeking status). Heterogeneity relating to covariates, task methodologies, and power limited conclusions.

CONCLUSIONS

Literature supports a postive association between choice impulsivity and BED. More research is needed to determine if individuals with BED demonstrate elevated levels of either rapid response impulsivity or types of compulsivity. Careful selection of covariates and consideration of task methodologies and power would aid future research.

Loss of control over eating: A systematic review of task based research into impulsive and compulsive processes in binge eating

Recurring episodes of excessive food intake in binge eating disorder can be understood through the lens of behavioral control systems: patients repeat maladaptive behaviors against their explicit intent. Self-report measures show enhanced impulsivity and compulsivity in binge eating (BE) but are agnostic as to the processes that might lead to impulsive and compulsive behavior in the moment. Task-based neurocognitive investigations can tap into those processes. In this systematic review, we synthesize neurocognitive research on behavioral impulsivity and compulsivity in BE in humans and animals, published between 2010-2020. Findings on impulsivity are heterogeneous. Findings on compulsivity are sparse but comparatively consistent, indicating an imbalance of goal-directed and habitual control as well as deficits in reversal learning. We urge researchers to address heterogeneity related to mood states and the temporal dynamics of symptoms, to systematically differentiate contributions of body weight and BE, and to ascertain the validity and reliability of tasks. Moreover, we propose to further scrutinize the compulsivity findings to unravel the computational mechanisms of a potential reinforcement learning deficit.

Contribution of Eye-Tracking to Study Cognitive Impairments Among Clinical Populations

In the field of psychology, the merge of decision-theory and neuroscientific methods produces an array of scientifically recognized paradigms. For example, by exploring consumer’s eye-movement behavior, researchers aim to deepen the understanding of how patterns of retinal activation are being meaningfully transformed into visual experiences and connected with specific reactions (e.g., purchase). Notably, eye-movements provide knowledge of one’s homeostatic balance and gatekeep information that shape decisions. Hence, vision science investigates the quality of observed environments determined under various experimental conditions. Moreover, it answers questions on how human process visual stimuli and use gained information for a successful strategy to achieve certain goals. While capturing cognitive states with the support of the eye-trackers progresses at a relatively fast pace in decision-making research, measuring the visual performance of real-life tasks, which require complex cognitive skills, is tentatively translated into clinical experiments. Nevertheless, the potential of the human eye as a highly valuable source of biomarkers has been underlined. In this article, we aim to draw readers attention to decision-making experimental paradigms supported with eye-tracking technology among clinical populations. Such interdisciplinary approach may become an important component that will (i) help in objectively illustrating patient’s models of beliefs and values, (ii) support clinical interventions, and (iii) contribute to health services. It is possible that shortly, eye-movement data from decision-making experiments will grant the scientific community a greater understanding of mechanisms underlining mental states and consumption practices that medical professionals consider as obsessions, disorders or addiction.

The role of the intestinal microbiota in eating disorders - bulimia nervosa and binge eating disorder

Bulimia nervosa (BN) and binge eating disorder (BED) are both eating disorders (EDs) characterised by episodes of overeating in which large amounts of food are consumed in short periods. The aetiology of BN and BED is not fully understood. Psychological and social factors influence the development of BN and BED, but biological factors such as neurohormones that regulate hunger and satiety, or neurotransmitters responsible for mood and anxiety play a significant role in sustaining symptoms. Increasing numbers of studies confirm the relationship between the composition of intestinal microbiota and the regulation of appetite, mood, and body mass. In this manuscript, we will describe the mechanisms by which intestinal dysbiosis can play an important role in the aetiology of binge eating episodes based on current understanding. Understanding the two-way relationship between BN and BED and alterations in the intestinal microbiota suggest the utility of new treatment methods of these disorders aimed at improving the composition of the intestinal microflora.

Diminished prefrontal cortex activation in patients with binge eating disorder associates with trait impulsivity and improves after impulsivity-focused treatment based on a randomized controlled IMPULS trial

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Persons with binge eating disorder show increased impulsivity.

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We investigated cognitive control to food cues using fNIRS.

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Compared to healthy controls, binge eaters show weaker activation of the prefrontal cortex.

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After behavioral therapy, binge eaters increase prefrontal cortex activation.

Background

Behavioral and cognitive control are vital for healthy eating behavior. Patients with binge eating disorder (BED) suffer under recurrent binge eating episodes accompanied by subjective loss of control that results, among other factors, from increased impulsivity.

Methods

In the current study, we investigated the frontal network using functional near-infrared spectroscopy (fNIRS) during a food specific go/nogo task to assess response inhibition in 24 patients with BED (BMI range 22.6–59.7 kg/m²) compared to 12 healthy controls (HC) (BMI range 20.9–27 kg/m²). Patients with BED were invited to undergo fNIRS measurements before an impulsivity-focused cognitive behavioral group treatment, directly after this treatment and 3 months afterwards. As this was a planned subgroup analysis of the randomized controlled IMPULS trial, patients with BED were randomized either to the treatment group (n = 14) or to a control group (n = 10). The treatment group received 8 weekly sessions of the IMPULS treatment.

Results

We found a significant response inhibition effect (nogo minus go), in terms of an increased oxygenated hemoglobin response in the bilateral prefrontal cortex in both groups. The greatest response was observed when participants were instructed to go for healthy and withhold their response to unhealthy high caloric food cues. The healthy nogo condition failed to show a significant prefrontal inhibitory response, which was probably related to the task design, as the condition was considered more demanding. BED patients, especially those with higher trait impulsivity, showed a weaker activation of the prefrontal cortex during response inhibition, predominantly in the right hemisphere. Interestingly, three months after the treatment, patients of the treatment group increased their right prefrontal cortex activity during response inhibition. Likewise, increased prefrontal cortex activation correlated with decreased trait impulsivity after treatment.

Conclusions

Our results suggest that patients with BED have limited resources to activate the prefrontal cortex when asked to inhibit a reaction onto food-specific stimuli. However, this effect could be partly driven by differences in BMI between the HC and BED group. Cognitive-behavioral therapy targeting impulsive eating behavior may improve prefrontal cortex recruitment during response inhibition.

Rewards that are near increase impulsive action

In modern society, the natural drive to behave impulsively in order to obtain rewards must often be curbed. A continued failure to do so is associated with a range of outcomes including drug abuse, pathological gambling, and obesity. Here, we used virtual reality technology to investigate whether spatial proximity to rewards has the power to exacerbate the drive to behave impulsively toward them. We embedded two behavioral tasks measuring distinct forms of impulsive behavior, impulsive action, and impulsive choice, within an environment rendered in virtual reality. Participants responded to three-dimensional cues representing food rewards located in either near or far space. Bayesian analyses revealed that participants were significantly less able to stop motor actions when rewarding cues were near compared with when they were far. Since factors normally associated with proximity were controlled for, these results suggest that proximity plays a distinctive role in driving impulsive actions for rewards.

Combined antisaccade task and transcranial direct current stimulation to increase response inhibition in binge eating disorder

Binge eating disorder (BED) is associated with deficient response inhibition. Malfunctioning response inhibition is linked to hypoactivation of the dorsolateral prefrontal cortex (dlPFC), where excitability could be increased by anodal transcranial direct current stimulation (tDCS). Response inhibition can be assessed using an antisaccade task which requires supressing a dominant response (i.e. saccade) towards a newly appearing picture in the visual field. We performed a double-blind, randomised, placebo-controlled proof-of-concept-study in which we combined a food-modified antisaccade task with tDCS in people with BED. We expected task learning and modulatory tDCS effects. Sixteen people were allocated to a 1 mA condition, 15 people to a 2 mA condition. Each participant underwent the food-modified antisaccade task at three measurement points: baseline without stimulation, anodal verum and sham stimulation at the right dlPFC in a crossover design. The error rate and the latencies of correct antisaccades decreased over time. No tDCS effect on the error rate could be observed. Compared to sham stimulation, 2 mA tDCS decreased the latencies of correct antisaccades, whereas 1 mA tDCS increased it. Self-reported binge eating episodes were reduced in the 2 mA condition, while there was no change in the 1 mA condition. Participants demonstrated increased response inhibition capacities by a task learning effect concerning the error rate and latencies of correct antisaccades over time as well as a nonlinear tDCS effect represented by ameliorated latencies in the 2 mA and impaired latencies in the 1 mA condition. The reduction of binge eating episodes might indicate a transfer effect to everyday life. Given that the reduction in binge eating was observed before tDCS administration, this effect could not be the result of neuromodulation. Randomized clinical trials are needed to fully understand this reduction, and to explore the efficacy of a combined antisaccade and tDCS training for BED.

Neural Correlates of Attentional Bias to Food Stimuli in Obese Adolescents

Adolescent obesity is an increasingly prevalent problem in several societies. Researchers have begun to focus on neurocognitive processes that may help explain how unhealthy food habits form and are maintained. The present study compared attentional bias to food stimuli in a sample of obese (n = 22) and Normal-weight (n = 18) adolescents utilizing an Attention Blink (AB) paradigm while electroencephalography (EEG) was recorded. We found lower accuracy and Event-Related Potential (ERP) P3 amplitudes during the presentation of food stimuli in AB trials for obese adolescents. These findings suggest an impaired ability of their brains to flexibly relocate attentional resources in the face of food stimuli. The results were corroborated by lower P3s also being associated with higher body mass index (BMI) values and poorer self-reported self-efficacy in controlling food intake. The study is among the few examining neural correlates of attentional control in obese adolescents and suggests automatic attentional bias to food is an important aspect to consider in tackling the obesity crisis.

The Neurobiology of Binge-eating Disorder Compared with Obesity: Implications for Differential Therapeutics

PURPOSE

Emerging work indicates divergence in the neurobiologies of binge-eating disorder (BED) and obesity despite their frequent co-occurrence. This review highlights specific distinguishing aspects of BED, including elevated impulsivity and compulsivity possibly involving the mesocorticolimbic dopamine system, and discusses implications for differential therapeutics for BED.

METHODS

This narrative review describes epidemiologic, clinical, genetic, and preclinical differences between BED and obesity. Subsequently, this review discusses human neuroimaging work reporting differences in executive functioning, reward processing, and emotion reactivity in BED compared with obesity. Finally, on the basis of the neurobiology of BED, this review identifies existing and new therapeutic agents that may be most promising given their specific targets based on putative mechanisms of action relevant specifically to BED.

FINDINGS

BED is characterized by elevated impulsivity and compulsivity compared with obesity, which is reflected in divergent neurobiological characteristics and effective pharmacotherapies. Therapeutic agents that influence both reward and executive function systems may be especially effective for BED.

IMPLICATIONS

Greater attention to impulsivity/compulsivity-related, reward-related, and emotion reactivity-related processes may enhance conceptualization and treatment approaches for patients with BED. Consideration of these distinguishing characteristics and processes could have implications for more targeted pharmacologic treatment research and interventions.

Attentional Bias to High-Calorie Food in Binge Eaters With High Shape/Weight Concern

Individuals with high shape/weight concern (SWC) place disproportionate emphasis on shape and weight in evaluating their self-worth, making them more vulnerable to body-related cues. Binge eaters (BE), who are obsessed with devouring high-calorie foods, would show severe symptomatology, especially when they have clinically high SWC. The present study attempted to elucidate how SWC influences binging based on attentional patterns toward high-calorie food cues. A total of 120 participants were selected and divided into four groups: (1) BE with high SWC, (2) BE with low SWC, (3) healthy controls (HC) with high SWC, and (4) HC with low SWC. BE and SWC status were respectively determined using the Eating Disorder Diagnostic Scale (DSM-5) and the Eating Disorder Examination Questionnaire. All participants completed the same free-viewing task, measuring initial fixation latency and total fixation duration. BE with high SWC showed attentional bias toward high-calorie food cues in terms of significantly faster initial fixation latency and longer total fixation duration, whereas BE with low SWC and the HC groups did not show any differences. The results revealed that SWC level makes unique contributions to BE's initial orienting bias toward and difficulty disengaging from high-calorie food cues. This may indicate that BE with high SWC merely worry about eating high-calorie food in a cognitive way, but not controlling actual binging behavior. The current study of attentional bias elucidated the role of SWC as a potential maintenance factor of being concerned and binging in BE.

Exploring Neural Mechanisms Related to Cognitive Control, Reward, and Affect in Eating Disorders: A Narrative Review of FMRI Studies

Studies using functional magnetic resonance imaging (fMRI) have contributed to our understanding of possible neural abnormalities among individuals with eating disorders. Many of these studies have focused on three domains: 1) cognitive control, 2) reward processing, and 3) affective processing. This review attempts to summarize the recent fMRI findings across these domains among the most well-characterized eating disorders: anorexia nervosa (AN), bulimia nervosa (BN), and binge eating disorder (BED). Though the literature is a bit murky, a few major themes have emerged. Cognitive control systems are affected among individuals across eating disorder diagnoses, but effects seem least pronounced in AN. Specifically, individuals with all eating disorders appear to show decreased prefrontal activation during cognitive control, but there is less evidence in AN linking decreased prefrontal activation with behavior. There is some evidence that the reinforcing value of food is reduced in AN, but individuals with BN and BED show hyperactivation to rewarding food-related stimuli, suggesting the reinforcing value of food may be enhanced. However, more complex reward processing paradigms show that individuals with BN and BED exhibit hypoactivation to reward anticipation and provide mixed results with regards to reward receipt. There are fewer neuroimaging findings related to affective processing, yet behavioral findings suggest affective processing is important in understanding eating disorders. Though the extant literature is complicated, these studies represent a foundation from which to build and provide insight into potential neurobiological mechanisms that may contribute to the pathophysiology of eating disorders.

A Perspective on Candidate Neural Underpinnings of Binge Eating Disorder: Reward and Homeostatic Systems

People with Binge Eating Disorder (BED) exhibit heightened sensitivity to rewarding stimuli and elevated activity in reward-related brain regions, including the orbitofrontal cortex (OFC), ventral striatum (VS) and insula, during food-cue exposure. BED has also been associated with altered patterns of functional connectivity during resting-state. Investigating neural connectivity in the absence of task stimuli provides knowledge about baseline communication patterns that may influence the behavioural and cognitive manifestation of BED. Elevated resting-state functional connectivity (rsFC) between reward-related brain regions may contribute to uncontrolled eating bouts observed in BED, through heightened food-cue sensitivity and food-craving. The impact of homeostatic state on rsFC of the reward system has not yet been investigated in people with BED. Homeostatic dysfunction is a key driver of excessive food consumption in obesity, whereby rsFC between rewardrelated brain regions does not attenuate during satiety. Future studies should investigate BED related differences in rsFC within the reward system during hunger and satiety, in order to determine whether individuals with BED display an abnormal neural response to changes in homeostatic state. This knowledge would further enhance current understandings of the mechanisms contributing to BED, potentially implicating both reward and homeostatic dysfunctions as drivers of BED.

Relationship between binge eating and associated eating behaviors with subcortical brain volumes and cortical thickness

BACKGROUND

Binge eating disorder (BED) is the most prevalent eating disorder. We examined the presence of binge eating (BE) and three associated eating behaviors in relation to subcortical regional volumes and cortical thickness from brain scans.

METHODS

We processed structural MRI brain scans for 466 individuals from the Nathan Kline Institute Rockland Sample using Freesurfer. We investigated subcortical volumes and cortical thicknesses among those with and without BE and in relation to the scores on dietary restraint, disinhibition, and hunger from the Three-Factor Eating Questionnaire (TFEQ). We conducted a whole-brain analysis and a region of analysis (ROI) using a priori regions associated with BE and with the three eating factors. We also compared scores on the three TFEQ factors for the BE and non-BE.

RESULTS

The BE group had higher scores for dietary restraint (p = .013), disinhibition (p = 1.22E-07), and hunger (p = 5.88E-07). In the whole-brain analysis, no regions survived correction for multiple comparisons (FDR corrected p<0.01) for either BE group or interaction with TFEQ. However, disinhibition scores correlated positively with left nucleus accumbens (NAc) volume (p < 0.01 FDR corrected). In the ROI analysis, those with BE also had greater left NAc volume (p = 0.008, uncorrected) compared to non-BE.

LIMITATIONS

Limitations include potential self-report bias on the EDE-Q and TFEQ.

CONCLUSIONS

The findings show that BE and disinhibition scores were each associated with greater volumes in the left NAc, a reward area, consistent with a greater drive and pleasure for food.

A characterization of binge planning behavior in individuals with binge-spectrum eating disorders

OBJECTIVE

Although binge eating is associated with impulsivity, clinical reports suggest that some individuals with bulimia nervosa (BN) and binge eating disorder (BED) plan binge episodes in advance. This study is the first to examine: (1) the frequency of binge planning (BP; defined as both advanced knowledge that a binge episode will occur and taking steps to facilitate the binge episode); (2) associations of BP with ED severity, and (3) whether BP serves a negative reinforcement function.

METHOD

Patients with BN- and BED-spectrum eating disorders (EDs; n = 111) were administered semi-structured interview questions regarding BP.

RESULTS

Results indicate that a substantial minority of patients (27.8%) engage in BP. BP was significantly more common in BN versus BED-spectrum EDs (38.3% versus 20.6%, p = 0.04) and in those who did versus did not endorse self-induced vomiting (50.0% versus 21.3%, p < 0.01). Frequency of BP was positively associated with overall ED psychopathology (r = 0.19, p < 0.05). Exploratory analyses indicated that approximately two-thirds (67.7%) reported that BP served to distract from unpleasant experiences.

DISCUSSION

BP is present for a significant subset of patients and may play a critical role in the reinforcement cycles of binge eating. Future research should further elucidate the function of BP to inform treatment development.