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.

Methylation of the OXTR gene in women with anorexia nervosa: Relationship to social behavior.

DNA methylation allows for the environmental regulation of gene expression and is believed to link environmental stressors to psychiatric disorder phenotypes, such as anorexia nervosa (AN). The oxytocin receptor (OXTR) gene is epigenetically regulated, and studies have shown associations between OXTR and social behaviours in various samples, including women with AN. The present study examined differential levels of methylation at various CG sites of the OXTR gene in 69 women with active AN (AN-Active), 21 in whom AN was in remission (AN-Rem) and 35 with no eating disorder (NED). Within each group, we explored the correlation between methylation and measures of social behaviour such as insecure attachment and social avoidance. Hypermethylation of a number of CG sites was seen in AN-Active participants as compared with AN-Rem and NED participants. In the AN-Rem sample, methylation at CG27501759 was significantly positively correlated with insecure attachment (r = .614, p = .003, permutation Q = 0.008) and social avoidance (r = .588, p = .005, permutation Q = 0.0184). Our results highlight differential methylation of the OXTR gene among women with AN, those in remission from AN, and those who never had AN and provide some evidence of associations between OXTR methylation and social behaviour in women remitted from AN.

Extending the Acquired Preparedness model of binge eating: Testing the indirect effects of high-risk personality traits on binge eating via positive and negative reinforcement expectancies.

According to the Acquired Preparedness (AP) model of binge eating, individuals high in negative urgency are more likely to develop the expectancy that eating alleviates negative affect, which in turn increases the likelihood of binge eating. Although both cross-sectional and longitudinal studies have provided strong support for the negative urgency version of the AP model, there are likely other personality traits and expectancies that may transact to increase risk for binge eating. We extended the AP model to examine how other high-risk personality traits related to reward and impulsivity might lead to binge eating via learned expectancies about eating. In a large sample of male and female college students (N = 998; 54.6% female), we tested the indirect effects of reward responsiveness, fun seeking, and sensation seeking on binge eating via expectancies related to positive and negative reinforcement from eating. Our results suggested an indirect effect of reward responsiveness on binge eating via the expectancy that eating is rewarding and an indirect effect of fun seeking on binge eating via the expectancies that eating is rewarding and eating alleviates boredom. In contrast, sensation seeking had neither direct nor indirect effects on binge eating. Findings suggest that there are multiple pathways from personality to binge eating that depend on differential learning experiences and should be considered in terms of prevention and treatment efforts.

Effort expenditure for rewards task modified for food: A novel behavioral measure of willingness to work for food.

OBJECTIVE: Binge eating and associated eating disorders are characterized by abnormalities in reward processing. One component of reward is willingness to expend effort to obtain a reinforcer. The Effort Expenditure for Rewards Task (EEfRT) is a widely used behavioral measure of willingness to work for money. We sought to modify the EEfRT to examine willingness to work for food reward and to preliminarily examine the association between binge eating and effort expenditure for food. METHOD: Participants were 63 females recruited to span the spectrum of binge-eating severity. The modified EEfRT required participants to make a series of choices between an easier, low-reward option (one portion of food) and a harder, high-reward option (between two to five portions of food). Each trial also varied on probability of winning. RESULTS: Participants self-reported engagement in the task, working hard at easy and hard tasks, and making choices based on reward probability and magnitude. As with the original EEfRT, probability, reward magnitude, and their interaction predicted the likelihood of choosing the hard task. Across two different measures, binge-eating symptoms interacted with reward magnitude, such that those with high binge eating used reward magnitude more to make trial choices than those with low binge eating. DISCUSSION: These data provide initial support for the validity of the EEfRT modified for food as a behavioral measure of willingness to work for food reward. The impact of binge eating on effort expenditure must be replicated in samples of patients with eating disorders.

Neurobiological foundations and clinical relevance of effort-based decision-making.

Applying effort-based decision-making tasks provides insights into specific variables influencing choice behaviors. The current review summarizes the structural and functional neuroanatomy of effort-based decision-making. Across 39 examined studies, the review highlights the ventromedial prefrontal cortex in forming reward-based predictions, the ventral striatum encoding expected subjective values driven by reward size, the dorsal anterior cingulate cortex for monitoring choices to maximize rewards, and specific motor areas preparing for effort expenditure. Neuromodulation techniques, along with shifting environmental and internal states, are promising novel treatment interventions for altering neural alterations underlying decision-making. Our review further articulates the translational promise of this construct into the development, maintenance and treatment of psychiatric conditions, particularly those characterized by reward-, effort- and valuation-related deficits.

Changing cannabis legislation in Canada and a longitudinal look at "regular" cannabis use in patients with eating disorders.

Regular cannabis use (CU), defined as "weekly or more often", is associated with a number of negative mental health outcomes. In the last decade, Canada legalized first medical and then recreational CU. Despite higher prevalence in mental health populations, little research has documented changes in frequency of CU with progressive legalization of cannabis. This study examined rates of CU in a sample of 843 treatment-seeking patients with eating disorders (ED) in an outpatient setting between 2004 and 2020. Across ED diagnoses, segmented regression indicated a significant break-point in regular CU in 2014, commensurate with the relaxation of medical cannabis laws. Regular CU increased from 4.9 % to 23.7 % from 2014 to 2020; well above the stable 6 % found in the general population. No significant break-point was observed in either alcohol or illicit substance use over the same time period. Significant increases in regular CU were found in patients with anorexia nervosa and binge eating disorder, while regular use remained stable in patients with bulimia nervosa. Comorbid psychiatric diagnoses did not increase odds of regular CU. Findings suggest certain patient groups with mental illness may be at risk of engaging in high frequency use in the context of legislation implying medical benefits of cannabis.

A review of effort-based decision-making in eating and weight disorders.

Effort-based decision-making provides a framework to understand the mental computations estimating the amount of work ("effort") required to obtain a reward. The aim of the current review is to systematically synthesize the available literature on effort-based decision-making across the spectrum of eating and weight disorders. More specifically, the current review summarises the literature examining whether 1) individuals with eating disorders and overweight/obesity are willing to expend more effort for rewards compared to healthy controls, 2) if particular components of effort-based decision-making (i.e. risk, discounting) relate to specific binge eating conditions, and 3) how individual differences in effort and reward -processing measures relate to eating pathology and treatment measures. A total of 96 studies were included in our review, following PRISMA guidelines. The review suggests that individuals with binge eating behaviours 1) are more likely to expend greater effort for food rewards, but not monetary rewards, 2) demonstrate greater decision-making impairments under risk and uncertainty, 3) prefer sooner rather than delayed rewards for both food and money, and 4) demonstrate increased implicit 'wanting' for high fat sweet foods. Finally, individual differences in effort and reward -processing measures relating to eating pathology and treatment measures are also discussed.

Delay Discounting in Established and Proposed Behavioral Addictions: A Systematic Review and Meta-Analysis.

Steep delay discounting, or a greater preference for smaller-immediate rewards over larger-delayed rewards, is a common phenomenon across a range of substance use and psychiatric disorders. Non-substance behavioral addictions (e.g., gambling disorder, internet gaming disorder, food addiction) are of increasing interest in delay discounting research. Individual studies have reported steeper discounting in people exhibiting various behavioral addictions compared to controls or significant correlations between discounting and behavioral addiction scales; however, not all studies have found significant effects. To synthesize the published research in this area and identify priorities for future research, we conducted a pre-registered systematic review and meta-analysis (following PRISMA guidelines) of delay discounting studies across a range of behavioral addiction categories. The final sample included 78 studies, yielding 87 effect sizes for the meta-analysis. For studies with categorical designs, we found statistically significant, medium-to-large effect sizes for gambling disorder (Cohen's d = 0.82) and IGD (d = 0.89), although the IGD effect size was disproportionately influenced by a single study (adjusted d = 0.53 after removal). Categorical internet/smartphone studies were non-significant (d = 0.16, p = 0.06). Aggregate correlations in dimensional studies were statistically significant, but generally small magnitude for gambling (r = 0.22), internet/smartphone (r = 0.13) and food addiction (r = 0.12). Heterogeneity statistics suggested substantial variability across studies, and publication bias indices indicated moderate impact of unpublished or small sample studies. These findings generally suggest that some behavioral addictions are associated with steeper discounting, with the most robust evidence for gambling disorder. Importantly, this review also highlighted several categories with notably smaller effect sizes or categories with too few studies to be included (e.g., compulsive buying, exercise addiction). Further research on delay discounting in behavioral addictions is warranted, particularly for categories with relatively few studies.