Is the relationship between binge eating episodes and personality attributable to genetic factors?

Associations Between Attention Deficit Hyperactivity Disorder Symptom Dimensions and Disordered Eating Symptoms in Adolescence: A Population-Based Twin Study

Although bivariate associations between attention-deficit/hyperactivity disorder (ADHD) and eating disorders in adolescent girls and boys have been previously identified, the mechanistic link underlying the symptom-level associations remains unclear. We evaluated shared genetic and environmental influences on ADHD symptoms and disordered eating in 819 female and 756 male twins from the Swedish TCHAD cohort using bivariate models. Common additive genetic and unique environmental effects accounted for majority of ADHD and disordered eating associations in a differential manner. For girls, the strongest genetic correlation was observed for cognitive/inattention problems-bulimia (0.54), with genetic factors accounting for 67% of the phenotypic correlation. For boys, the strongest genetic correlations were observed for conduct problems-bulimia and hyperactivity-bulimia (~ 0.54), accounting for 83% and 95% of the phenotypic correlation, respectively. As per our findings, the risk of comorbidity and shared genetics highlights the need for preventative measures and specialized treatment for ADHD and disordered eating in both sexes.

Risk factors for eating disorders: findings from a rapid review

BACKGROUND

Risk factors represent a range of complex variables associated with the onset, development, and course of eating disorders. Understanding these risk factors is vital for the refinement of aetiological models, which may inform the development of targeted, evidence-based prevention, early intervention, and treatment programs. This Rapid Review aimed to identify and summarise research studies conducted within the last 12 years, focusing on risk factors associated with eating disorders.

METHODS

The current review forms part of a series of Rapid Reviews to be published in a special issue in the Journal of Eating Disorders, funded by the Australian Government to inform the development of the National Eating Disorder Research and Translation Strategy 2021-2031. Three databases were searched for studies published between 2009 and 2021, published in English, and comprising high-level evidence studies (meta-analyses, systematic reviews, moderately sized randomised controlled studies, moderately sized controlled-cohort studies, or population studies). Data pertaining to risk factors for eating disorders were synthesised and outlined in the current paper.

RESULTS

A total of 284 studies were included. The findings were divided into nine main categories: (1) genetics, (2) gastrointestinal microbiota and autoimmune reactions, (3) childhood and early adolescent exposures, (4) personality traits and comorbid mental health conditions, (5) gender, (6) socio-economic status, (7) ethnic minority, (8) body image and social influence, and (9) elite sports. A substantial amount of research exists supporting the role of inherited genetic risk in the development of eating disorders, with biological risk factors, such as the role of gut microbiota in dysregulation of appetite, an area of emerging evidence. Abuse, trauma and childhood obesity are strongly linked to eating disorders, however less conclusive evidence exists regarding developmental factors such as role of in-utero exposure to hormones. Comorbidities between eating disorders and mental health disorders, including personality and mood disorders, have been found to increase the severity of eating disorder symptomatology. Higher education attainment, body image-related factors, and use of appearance-focused social media are also associated with increased risk of eating disorder symptoms.

CONCLUSION

Eating disorders are associated with multiple risk factors. An extensive amount of research has been conducted in the field; however, further studies are required to assess the causal nature of the risk factors identified in the current review. This will assist in understanding the sequelae of eating disorder development and in turn allow for enhancement of existing interventions and ultimately improved outcomes for individuals.

Shared Genetic Factors Contributing to the Overlap between Attention-Deficit/Hyperactivity Disorder Symptoms and Overweight/Obesity in Swedish Adolescent Girls and Boys

Attention-deficit/hyperactivity disorder (ADHD) and obesity are positively associated, with increasing evidence that they share genetic risk factors. Our aim was to examine whether these findings apply to both types of ADHD symptoms for female and male adolescents. We used data from 791 girl and 735 boy twins ages 16-17 years to examine sex-specific phenotypic correlations between the presence of ADHD symptoms and overweight/obese status. For correlations exceeding .20, we then fit bivariate twin models to estimate the genetic and environmental correlations between the presence of ADHD symptoms and overweight/obese status. ADHD symptoms and height/weight were parent- and self-reported, respectively. Phenotypic correlations were .30 (girls) and .08 (boys) for inattention and overweight/obese status and .23 (girls) and .14 (boys) for hyperactivity/impulsivity and overweight/obese status. In girls, both types of ADHD symptoms and overweight/obese status were highly heritable, with unique environmental effects comprising the remaining variance. Furthermore, shared genetic effects explained most of the phenotypic correlations in girls. Results suggest that the positive association of both types of ADHD symptoms with obesity may be stronger in girls than boys. Further, in girls, these associations may stem primarily from shared genetic factors.

Exploring the possibility of parents' broad internalizing phenotype acting through passive gene-environment correlations on daughters' disordered eating

Twin studies demonstrate significant environmental influences and a lack of genetic effects on disordered eating before puberty in girls. However, genetic factors could act indirectly through passive gene-environment correlations (rGE; correlations between parents' genes and an environment shaped by those genes) that inflate environmental (but not genetic) estimates. The only study to explore passive rGE did not find significant effects, but the full range of parental phenotypes (e.g., internalizing symptoms) that could impact daughters' disordered eating was not examined. We addressed this gap by exploring whether parents' internalizing symptoms (e.g., anxiety, depressive symptoms) contribute to daughters' eating pathology through passive rGE. Participants were female twin pairs (aged 8-14 years; M = 10.44) in pre-early puberty and their biological parents (n = 279 families) from the Michigan State University Twin Registry. Nuclear twin family models explored passive rGE for parents' internalizing traits/symptoms and twins' overall eating disorder symptoms. No evidence for passive rGE was found. Instead, environmental factors that create similarities between co-twins (but not with their parents) and unique environmental factors were important. In pre-early puberty, genetic factors do not influence daughters' disordered eating, even indirectly through passive rGE. Future research should explore sibling-specific and unique environmental factors during this critical developmental period.

Is there a relationship between personality traits and fruit and vegetable intake among pregnant women?

Previous studies have shown that certain personality traits such as neuroticism and conscientiousness influence dietary choices. Pregnancy is a unique period in a woman’s life during which most women are highly intrinsically and extrinsically motivated to start a diet rich in fruit and vegetables. Yet, an adequate consumption of fruits and vegetables remains a challenge for many women. The present study investigates the relationships between personality traits and fish, dairy, fruit, and vegetable intake. Data was collected from 602 pregnant women and analyzed using descriptive statistics and hierarchical regression analyses in order to examine predictive relationships between the variables of interest. The results demonstrated that high scores in openness to experience, older maternal age, higher income, and educational attainment were positively associated with increased fish, vegetable, and fruit intake. These findings have important implications for interventions that seek to improve eating behaviors of pregnant women, thereby increasing the health of their pregnancies.

The Direct and Indirect Effects of Online Social Support, Neuroticism, and Web Content Internalization on the Drive for Thinness among Women Visiting Health-Oriented Websites

One of the debates about media usage is the potential harmful effect that it has on body image and related eating disturbances because of its representations of the “ideal body”. This study focuses on the drive for thinness among the visitors of various health-oriented websites and online platforms because neither has yet been sufficiently studied in this context. Specifically, this study aims to bring more insight to the risk factors which can increase the drive for thinness in the users of these websites. We tested the presumption that web content internalization is a key factor in this process, and we considered the effects of selected individual factors, specifically the perceived online social support and neuroticism. We utilized survey data from 445 Czech women (aged 18–29, M = 23.5, SD = 3.1) who visited nutrition, weight loss, and exercise websites. The results showed a positive indirect link between both perceived online social support and neuroticism to the drive for thinness via web content internalization. The results are discussed with regard to the dual role of online support as both risk and protective factor. Moreover, we consider the practical implications for eating behavior and weight-related problems with regard to prevention and intervention.

[Genetics factors in pathogenesis and clinical genetics of binge eating disorder]

Genetic studies have shown that binge eating disorder (ВЕD) aggregates in families, heritability was estimated as about 60% and additive genetic influences on BED up to 50%. Using a genetic approach has proved useful for verifying the diagnostic categories of BED using DSM-IV criteria and supporting the validity of considering this pathology as a separate nosological category. The results confirmed the genetic and pathogenic originality of BED as a separate psychopathological phenomenon, but not a subtype of obesity. It seems fruitful to considerate BED as a disease with hereditary predisposition with significant genetic influence and a complex psychopathological syndrome, including not only eating disorders, but also depressive and addictive component. A possible mechanism of pathogenesis of BED may be the interaction of the neuroendocrine and neurotransmitters systems including the active involvement of the reward system in response to a variety of chronic stress influences with the important modulatory role of specific personality traits. The high level of genetic influence on the certain clinical manifestations of BED confirms the ability to identify the subphenotypes of BED on genetic basis involving clinical criteria. It can not only contribute to further genetic studies, taking into account more homogeneous samples, but also help in finding differentiated therapeutic approaches.

Shared familial risk between bulimic symptoms and alcohol involvement during adolescence

Twin studies show the established relation between bulimic symptoms and problematic alcohol involvement in adult females is partly due to shared familial factors, specifically shared genetic effects. However, it is unclear if similar shared etiological factors exist during adolescence or in males. We examined the familial overlap (i.e., genetic and common environmental correlations) between bulimic symptoms and various levels of alcohol involvement in 16- to 17-year-old female and male same-sex twin pairs using sex-specific biometrical twin modeling. Bulimic symptoms were assessed with the Eating Disorder Inventory-2. Alcohol involvement included alcohol use in the last month, having ever been intoxicated, and alcohol intoxication frequency. Results revealed 3 distinct patterns. First, in general, phenotypic correlations indicated statistically similar associations between bulimic symptoms and alcohol involvement in girls and boys. Second, common environmental overlap was significant for the bivariate associations including having ever been intoxicated. Third, moderate genetic correlations were observed between all bulimic symptoms and alcohol involvement in girls and moderate common environmental correlations were observed in boys for the more risky/deviant levels of involvement. Similar to adults, there is familial overlap between bulimic symptoms and alcohol involvement in adolescent girls and boys. These results could inform symptom- and sex-specific, developmentally targeted prevention and intervention programs for the comorbidity between bulimic symptoms and alcohol involvement. (PsycINFO Database Record

Associations of Neuroticism and Impulsivity with Binge Eating in a Nationally Representative Sample of Adolescents in the United States

Binge eating behavior is a public health concern with serious physical and mental health consequences. Certain personality traits have been found to contribute to the development of eating disorders in clinical samples of youth, but little is known about associations between personality traits and binge eating in the general adolescent population. We examined the associations of neuroticism and impulsivity-both independently and in combination-with lifetime prevalence of binge eating, using nationally representative, cross-sectional data from the National Comorbidity Survey: Adolescent Supplement (n=437). Neuroticism and impulsivity were each significantly associated with lifetime prevalence of binge eating (adjusted prevalence ratio [aPR]=1.11, confidence interval [CI]=1.07, 1.15, p<0.001; aPR=1.06, CI=1.04, 1.09, p<0.001, respectively). The combination of high neuroticism and high impulsivity was associated with higher lifetime binge eating than the combination of low neuroticism and low impulsivity (aPR=3.72, CI=2.45, 5.65, p<0.001), and this association was stronger for female than male adolescents (females: aPR=5.37, CI=3.24, 8.91, p<0.001 vs. males: aPR=2.45, CI=1.43, 4.22, p=0.002). Our findings have implications for informing theories of etiology and interventions to target binge eating behaviors.

[Genetic aspects of binge eating disorder Part 2. Molecular genetics and pharmacogenetic approaches]

Genetic risk of binge eating disorder (ВЕD) is a consequence of joint participation of many genes, the contribution of each one is small, but the total (additive) effect is significant and greatly influences the age at onset, clinical dynamics and the level of treatment resistance. It is assumed that the carriers of different polymorphic variants of genes and their combinations have different levels of genetic risk. No Genom Wide Association studies of ВЕD has been performed and the analysis of the results of candidate genes studies gives reason to believe that pathogenetically substantiated panel of genes, including serotonin system, BDNF and, especially dopamine and endogenous opioid system, would be most useful, taking into account the mechanism of action of drugs for the ВЕD treatment. Genetic studies with this panel if using evidence-based design, detailed and quantitative analysis of the family history of binge eating can give good results for: 1) assessment of the genetic risk of ВЕD for primary prevention programs; 2) identification of the specific clinical forms of development and course of ВЕD with significant genetic influence; 3) identification of the specific genetic variants that increase the effectiveness of personalized pharmacotherapy of ВЕD within pharmacogenetic approach.

Research Review: What we have learned about the causes of eating disorders - a synthesis of sociocultural, psychological, and biological research

BACKGROUND

Eating disorders are severe psychiatric disorders with a complex etiology involving transactions among sociocultural, psychological, and biological influences. Most research and reviews, however, focus on only one level of analysis. To address this gap, we provide a qualitative review and summary using an integrative biopsychosocial approach.

METHODS

We selected variables for which there were available data using integrative methodologies (e.g., twin studies, gene-environment interactions) and/or data at the biological and behavioral level (e.g., neuroimaging). Factors that met these inclusion criteria were idealization of thinness, negative emotionality, perfectionism, negative urgency, inhibitory control, cognitive inflexibility, serotonin, dopamine, ovarian hormones. Literature searches were conducted using PubMed. Variables were classified as risk factors or correlates of eating disorder diagnoses and disordered eating symptoms using Kraemer et al.'s (1997) criteria.

FINDINGS

Sociocultural idealization of thinness variables (media exposure, pressures for thinness, thin-ideal internalization, thinness expectancies) and personality traits (negative emotionality, perfectionism, negative urgency) attained 'risk status' for eating disorders and/or disordered eating symptoms. Other factors were identified as correlates of eating pathology or were not classified given limited data. Effect sizes for risk factors and correlates were generally small-to-moderate in magnitude.

CONCLUSIONS

Multiple biopsychosocial influences are implicated in eating disorders and/or disordered eating symptoms and several can now be considered established risk factors. Data suggest that psychological and environmental factors interact with and influence the expression of genetic risk to cause eating pathology. Additional studies that examine risk variables across multiple levels of analysis and that consider specific transactional processes amongst variables are needed to further elucidate the intersection of sociocultural, psychological, and biological influences on eating disorders.

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

BACKGROUND

Pediatric loss-of-control (LOC) eating is a robust behavioral precursor to binge-type eating disorders. Elucidating precursors to LOC eating and binge-type eating disorders may refine developmental risk models of eating disorders and inform interventions.

METHOD

We review evidence within constructs of the Negative Valence Systems (NVS) domain, as specified by the Research Domain Criteria framework. Based on published studies, we propose an integrated NVS model of binge-type eating-disorder risk.

RESULTS

Data implicate altered corticolimbic functioning, neuroendocrine dysregulation, and self-reported negative affect as possible risk factors. However, neuroimaging and physiological data in children and adolescents are sparse, and most prospective studies are limited to self-report measures.

CONCLUSIONS

We discuss a broad NVS framework for conceptualizing early risk for binge-type eating disorders. Future neural and behavioral research on the developmental trajectory of LOC and binge-type eating disorders is required.