Familiality and heritability of binge eating disorder: results of a case-control family study and a twin study

Neuroimaging studies of resting-state functional magnetic resonance imaging in eating disorders

Eating disorders (EDs), including anorexia nervosa (AN), bulimia nervosa (BN), binge-eating disorder (BED), and pica, are psychobehavioral conditions characterized by abnormal eating behaviors and an excessive preoccupation with weight and body shape. This review examines changes in brain regions and functional connectivity in ED patients over the past decade (2013-2023) using resting-state functional magnetic resonance imaging (rs-fMRI). Key findings highlight alterations in brain networks such as the default mode network (DMN), central executive network (CEN), and emotion regulation network (ERN). In individuals with AN, there is reduced functional connectivity in areas associated with facial information processing and social cognition, alongside increased connectivity in regions linked to sensory stimulation, aesthetic judgment, and social anxiety. Conversely, BED patients show diminished connectivity in the dorsal anterior cingulate cortex within the salience network and increased connectivity in the posterior cingulate cortex and medial prefrontal cortex within the DMN. These findings suggest that rs-fMRI could serve as a valuable biomarker for assessing brain function and predicting treatment outcomes in EDs, paving the way for personalized therapeutic strategies.

Shared Genetic Influences Between Loss-of-Control Eating and Body Mass Index in Adolescent Twins

OBJECTIVE

Pediatric loss-of-control (LOC) eating is associated with high BMI and predicts binge-eating disorder and obesity onset with age. Research on the etiology of this common comorbidity has not explored the potential for shared genetic risk. This study examined genetic and environmental influences on LOC eating and its shared influence with BMI.

METHOD

Participants were 499 monozygotic and 398 same-sex dizygotic twins (age = 17.38 years ± 0.67, BMIz = 0.03 ± 1.03, 54% female) from the Colorado Center for Antisocial Drug Dependence Study. LOC eating was assessed dichotomously. Self-reported height and weight were converted to BMIz. Univariate and bivariate twin models estimated genetic and environmental influences on LOC eating and BMIz.

RESULTS

More girls (21%) than boys (9%, p < 0.001) reported LOC eating. The phenotypic correlation with BMIz was 0.03 in girls and 0.18 in boys. Due to the nonsignificant phenotypic correlation in girls, bivariate twin models were fit in boys only. Across all models, the best-fitting model included genetic and unique environmental effects. Genetic factors accounted for 0.51 (95% CI: 0.23, 0.73) of the variance of LOC eating in girls and 0.54 (0.18, 0.90) in boys. The genetic correlation between LOC eating and BMIz in boys was 0.45 (0.15, 0.75).

DISCUSSION

Findings indicate moderate heritability of LOC eating in adolescence, while emphasizing the role of unique environmental factors. In boys, LOC eating and BMIz share a proportion of their genetic influences.

The natural course of binge-eating disorder: findings from a prospective, community-based study of adults

BACKGROUND

Epidemiological data offer conflicting views of the natural course of binge-eating disorder (BED), with large retrospective studies suggesting a protracted course and small prospective studies suggesting a briefer duration. We thus examined changes in BED diagnostic status in a prospective, community-based study that was larger and more representative with respect to sex, age of onset, and body mass index (BMI) than prior multi-year prospective studies.

METHODS

Probands and relatives with current DSM-IV BED (n = 156) from a family study of BED ('baseline') were selected for follow-up at 2.5 and 5 years. Probands were required to have BMI > 25 (women) or >27 (men). Diagnostic interviews and questionnaires were administered at all timepoints.

RESULTS

Of participants with follow-up data (n = 137), 78.1% were female, and 11.7% and 88.3% reported identifying as Black and White, respectively. At baseline, their mean age was 47.2 years, and mean BMI was 36.1. At 2.5 (and 5) years, 61.3% (45.7%), 23.4% (32.6%), and 15.3% (21.7%) of assessed participants exhibited full, sub-threshold, and no BED, respectively. No participants displayed anorexia or bulimia nervosa at follow-up timepoints. Median time to remission (i.e. no BED) exceeded 60 months, and median time to relapse (i.e. sub-threshold or full BED) after remission was 30 months. Two classes of machine learning methods did not consistently outperform random guessing at predicting time to remission from baseline demographic and clinical variables.

CONCLUSIONS

Among community-based adults with higher BMI, BED improves with time, but full remission often takes many years, and relapse is common.

The children of parents who receive treatment for binge-eating disorder experience improvements in disordered eating

OBJECTIVE

Parental eating disorders are associated with disordered eating behaviors and psychopathology in their children, but it is not known whether parent treatment for binge-eating disorder (BED) is associated with changes in child disordered eating behaviors and weight. Benefits or the "ripple" effect of treatment on untreated family members has been described in the obesity literature but not for BED.

METHOD

Participants evaluated for two randomized clinical trials for BED were screened for whether they had children. 76 parents completed baseline assessments about a school-aged child; 62 were randomized to treatment, of whom 41 completed end-of-treatment assessments about their child's eating behaviors and weight (which were not targeted in the parent treatments).

RESULTS

Analyses revealed a significant effect of time on children's binge-eating frequency and perceived weight category and a significant effect of parent medication on perceived weight category. Parental change in binge eating was associated significantly with changes in child secretive eating and food hoarding. Parental change in weight was not associated significantly with change in age/sex-normed child BMI percentile, but had some associations with parent-perceived child weight category.

CONCLUSIONS

Parent changes during their treatment were associated with changes in their children. Future longitudinal research is needed to examine when disordered eating emerges and clarify critical intervention timing related to children's age and parental BED. Further clinical research is also needed to assess the effectiveness of treating disordered eating at the family level.

PUBLIC SIGNIFICANCE

Prior cross-sectional work has found that parents with BED are more likely to have children who engage in binge eating compared to parents without eating-disorder psychopathology. This study was an initial exploration of change in children when parents received treatment in randomized controlled trials for BED. In this study, parent changes in binge eating were associated with reduced child secretive eating and food hoarding.

ARFID Genes and Environment (ARFID-GEN): study protocol

BACKGROUND

The Avoidant Restrictive Food Intake Disorder - Genes and Environment (ARFID-GEN) study is a study of genetic and environmental factors that contribute to risk for developing ARFID in children and adults.

METHODS

A total of 3,000 children and adults with ARFID from the United States will be included. Parents/guardians and their children with ARFID (ages 7 to 17) and adults with ARFID (ages 18 +) will complete comprehensive online consent, parent verification of child assent (when applicable), and phenotyping. Enrolled participants with ARFID will submit a saliva sample for genotyping. A genome-wide association study of ARFID will be conducted.

DISCUSSION

ARFID-GEN, a large-scale genetic study of ARFID, is designed to rapidly advance the study of the genetics of eating disorders. We will explicate the genetic architecture of ARFID relative to other eating disorders and to other psychiatric, neurodevelopmental, and metabolic disorders and traits. Our goal is for ARFID to deliver "actionable" findings that can be transformed into clinically meaningful insights.

TRIAL REGISTRATION

ARFID-GEN is a registered clinical trial: clinicaltrials.gov NCT05605067.

Genome-wide analysis of a model-derived binge eating disorder phenotype identifies risk loci and implicates iron metabolism

Binge eating disorder (BED) is the most common eating disorder, yet its genetic architecture remains largely unknown. Studying BED is challenging because it is often comorbid with obesity, a common and highly polygenic trait, and it is underdiagnosed in biobank data sets. To address this limitation, we apply a supervised machine-learning approach (using 822 cases of individuals diagnosed with BED) to estimate the probability of each individual having BED based on electronic medical records from the Million Veteran Program. We perform a genome-wide association study of individuals of African (n = 77,574) and European (n = 285,138) ancestry while controlling for body mass index to identify three independent loci near the HFE, MCHR2 and LRP11 genes and suggest APOE as a risk gene for BED. We identify shared heritability between BED and several neuropsychiatric traits, and implicate iron metabolism in the pathophysiology of BED. Overall, our findings provide insights into the genetics underlying BED and suggest directions for future translational research.

Arfid Genes and Environment (ARFID-GEN): Study Protocol

Background

The Avoidant Restrictive Food Intake Disorder Genes and Environment (ARFID-GEN) study is a study of genetic and environmental factors that contribute to risk for developing ARFID in children and adults.

Methods

A total of 3,000 children and adults with ARFID from the United States will be included. Parents/guardians and their children with ARFID (ages 7 to 17) and adults with ARFID (ages 18+) will complete comprehensive online consent, parent verification of child assent (when applicable), and phenotyping. Enrolled participants with ARFID will submit a saliva sample for genotyping. A genome-wide association study of ARFID will be conducted.

Discussion

ARFID-GEN, a large-scale genetic study of ARFID, is designed to rapidly advance the study of the genetics of eating disorders. We will explicate the genetic architecture of ARFID relative to other eating disorders and to other psychiatric, neurodevelopmental, and metabolic disorders and traits. Our goal is for ARFID to deliver "actionable" findings that can be transformed into clinically meaningful insights.

Trial registration

ARFID-GEN is a registered clinical trial: clinicaltrials.gov NCT05605067.

Mechanisms by which adverse childhood experiences, other traumas and PTSD influence the health and well-being of individuals with eating disorders throughout the life span

BACKGROUND

Multiple published sources from around the world have confirmed an association between an array of adverse childhood experiences (ACEs) and other traumatic events with eating disorders (EDs) and related adverse outcomes, including higher morbidity and mortality.

METHODS

In keeping with this Special Issue's goals, this narrative review focuses on the ACEs pyramid and its purported mechanisms through which child maltreatment and other forms of violence toward human beings influence the health and well-being of individuals who develop EDs throughout the life span. Relevant literature on posttraumatic stress disorder (PTSD) is highlighted when applicable.

RESULTS

At every level of the pyramid, it is shown that EDs interact with each of these proclaimed escalating mechanisms in a bidirectional manner that contributes to the predisposition, precipitation and perpetuation of EDs and related medical and psychiatric comorbidities, which then predispose to early death. The levels and their interactions that are discussed include the contribution of generational embodiment (genetics) and historical trauma (epigenetics), social conditions and local context, the ACEs and other traumas themselves, the resultant disrupted neurodevelopment, subsequent social, emotional and cognitive impairment, the adoption of health risk behaviors, and the development of disease, disability and social problems, all resulting in premature mortality by means of fatal complications and/or suicide.

CONCLUSIONS

The implications of these cascading, evolving, and intertwined perspectives have important implications for the assessment and treatment of EDs using trauma-informed care and trauma-focused integrated treatment approaches. This overview offers multiple opportunities at every level for the palliation and prevention of EDs and other associated trauma-related conditions, including PTSD.

Potential eating disorder exhibited with daytime functional vulnerabilities associated with sleep problems in Japanese adolescents: A cross-sectional study

OBJECTIVES

Eating disorders (ED) are serious psychiatric disorders that affect individuals, especially adolescents. It has been suggested that nonclinical ED-like characteristics are related to sleep problems. We conducted a survey of Japanese adolescents to investigate this claim.

METHOD

In this cross-sectional study, 398 adolescents aged 12-18 years responded to a self-administered questionnaire survey. We used the Eating Attitudes Test-26 (EAT-26) and the Athens Insomnia Scale (AIS) to measure potential ED and sleep problems, respectively.

RESULTS

Adolescents with potential ED had significantly higher daytime functional vulnerability potentially associated with sleep problems than those without ED. In particular, problems with a sense of well-being and physical and mental functioning during the day were significant. In contrast, no significant associations were found between potential ED and sleep initiation, awakenings during the night, early morning awakening, total sleep duration, or overall quality of sleep. Finally, nocturnal and daytime sleep scores were significantly associated with dieting, bulimia, and oral control EAT-26 subscores.

DISCUSSION

Participants with possible ED experienced problems related to well-being and mental and physical functioning, which are indicators of daytime functional vulnerability potentially associated with sleep problems. Further, adolescents with more severe ED characteristics are more likely to have a higher degree of daytime psychological vulnerability potentially attributable to sleep problems. The study suggested that professionals treating adolescent mental health issues need an approach that comprehensively integrates both sleep problems and potential ED.

Binge Eating Disorder Is a Social Justice Issue: A Cross-Sectional Mixed-Methods Study of Binge Eating Disorder Experts' Opinions

BACKGROUND

Binge eating disorder is an autonomous DSM-V diagnosis characterized by discrete rapid consumption of objectively large amounts of food without compensation, associated with loss of control and distress. Environmental factors that contribute to binge eating disorder continue to evolve. This mixed-methods cross-sectional study assessed whether there is consensus among experts in the field about environmental factors that influence adult binge eating disorder pathology.

METHODS

Fourteen expert binge eating disorder researchers, clinicians, and healthcare administrators were identified internationally based on federal funding, PubMed-indexed publications, active practice in the field, leadership in relevant societies, and/or clinical and popular press distinction. Semi-structured interviews were recorded anonymously and analyzed by ≥2 investigators using reflexive thematic analysis and quantification.

RESULTS

Identified themes included: (1) systemic issues and systems of oppression (100%); (2) marginalized and under-represented populations (100%); (3) economic precarity and food/nutrition insecurity/scarcity (93%); (4) stigmatization and its psychological impacts (93%); (5) trauma and adversity (79%); (6) interpersonal factors (64%); (7) social messaging and social media (50%); (8) predatory food industry practices (29%); and (9) research/clinical gaps and directives (100%).

CONCLUSIONS

Overall, experts call for policy changes around systemic factors that abet binge eating and for greater public education about who can have binge eating disorder. There is also a call to take and account for the narratives and life experiences of individuals with binge eating disorder to better inform our current understanding of the diagnosis and the environmental factors that impact it.

Binge eating disorder

Binge eating disorder (BED) is characterized by regular binge eating episodes during which individuals ingest comparably large amounts of food and experience loss of control over their eating behaviour. The worldwide prevalence of BED for the years 2018-2020 is estimated to be 0.6-1.8% in adult women and 0.3-0.7% in adult men. BED is commonly associated with obesity and with somatic and mental health comorbidities. People with BED experience considerable burden and impairments in quality of life, and, at the same time, BED often goes undetected and untreated. The aetiology of BED is complex, including genetic and environmental factors as well as neuroendocrinological and neurobiological contributions. Neurobiological findings highlight impairments in reward processing, inhibitory control and emotion regulation in people with BED, and these neurobiological domains are targets for emerging treatment approaches. Psychotherapy is the first-line treatment for BED. Recognition and research on BED has increased since its inclusion into DSM-5; however, continuing efforts are needed to understand underlying mechanisms of BED and to improve prevention and treatment outcomes for this disorder. These efforts should also include screening, identification and implementation of evidence-based interventions in routine clinical practice settings such as primary care and mental health outpatient clinics.

Genetics of eating disorders in the genome-wide era

Enabled by advances in high throughput genomic sequencing and an unprecedented level of global data sharing, molecular genetic research is beginning to unlock the biological basis of eating disorders. This invited review provides an overview of genetic discoveries in eating disorders in the genome-wide era. To date, five genome-wide association studies on eating disorders have been conducted - all on anorexia nervosa (AN). For AN, several risk loci have been detected, and ~11-17% of the heritability has been accounted for by common genetic variants. There is extensive genetic overlap between AN and psychological traits, especially obsessive-compulsive disorder, and intriguingly, with metabolic phenotypes even after adjusting for body mass index (BMI) risk variants. Furthermore, genetic risk variants predisposing to lower BMI may be causal risk factors for AN. Causal genes and biological pathways of eating disorders have yet to be elucidated and will require greater sample sizes and statistical power, and functional follow-up studies. Several studies are underway to recruit individuals with bulimia nervosa and binge-eating disorder to enable further genome-wide studies. Data collections and research labs focused on the genetics of eating disorders have joined together in a global effort with the Psychiatric Genomics Consortium. Molecular genetics research in the genome-wide era is improving knowledge about the biology behind the established heritability of eating disorders. This has the potential to offer new hope for understanding eating disorder etiology and for overcoming the therapeutic challenges that confront the eating disorder field.

THE CHALLENGES OF METABOLIC SYNDROME IN EATING DISORDERS

A number of studies have examined the association of the three major eating disorders - anorexia nervosa, bulimia nervosa, and binge-eating disorder - with metabolic syndrome, or with individual components of metabolic syndrome, such as obesity, type 2 diabetes, hypertension, and dyslipidemia. Present evidence suggests that anorexia nervosa confers no excess risk of metabolic syndrome and may be associated with lower risk of certain metabolic syndrome components, including obesity and type 2 diabetes. Bulimia nervosa shows associations with increased risk for metabolic syndrome components in some studies, but not in others. Binge-eating disorder, however, is strongly associated with increased risk for both metabolic syndrome and its components - and these associations appear to be mediated not only through elevated body weight, but also possible body-weight-independent factors. Given that binge-eating disorder is the most common eating disorder, treatment and prevention of metabolic syndrome in this group represents a significant clinical and public health challenge.

Executive functions and depressive symptoms interplay in binge eating disorder: A structural equation model analysis

OBJECTIVE

Executive functions (EF) have been so far investigated as potential endophenotypes for binge eating disorder (BED). However, major critical limitations in previous research, such as the influence of obesity and comorbid depression, prevented any consensus to be reached. The present study investigated the association between depressive symptoms, a broad range of EF and binge eating severity in individuals with obesity and with/without BED, and whether this association may be explained by a mediation or independency model.

METHOD

One hundred and seven participants completed clinical and psychometric examination. Associations between EF, depressive symptoms and binge eating severity were assessed through bivariate correlation analysis, and the magnitude, as well as the direction of associations between variables, was estimated with structural equation model.

RESULTS

Two reliable models were tested; results showed that depressive symptoms exhibited significant direct and indirect effects on the severity of binge eating; conversely, EF did not show either significant direct or indirect effect on binge eating severity.

CONCLUSION

Depression contributes more than EF to psychopathology of BED. Thus, clinicians should routinely assess and, eventually, tailor depressive symptoms in treatment to improve the outcomes of patients with BED.

No association between dopaminergic polymorphisms and response to treatment of binge-eating disorder

BACKGROUND

The genetics of binge-eating disorder (BED) is an emerging topic, with dopaminergic genes being implicated in its etiology due to the role that dopamine (DA) plays in food reward sensitivity and self-regulation of eating behavior. However, no study to date has examined if DA genes influence response to behavioral treatment of BED.

OBJECTIVE

The primary objective of this study was to examine the ability of DA-associated polymorphisms to predict BED treatment response measured using binge frequency over 12 months. As secondary objectives, this study examined cross-sectional relationships between these polymorphisms and anthropometrics in women living with and without BED and obesity.

METHODS

Women aged 18-64 years old were genotyped for the DA-related SNPs DRD2/ANKK1 Taq1A (rs1800497) and COMT (rs4680), as well as the DA-related uVNTRs DAT-1 (SLC6A3) and MAO-A. A multi-locus DA composite score was formed from these 4 polymorphisms using genotypes known to have a functional impact resulting in modified DA signaling. Binge frequency (Eating Disorder Examination - Interview) and body composition (Tanita BC-418) were assessed in a pre-post analysis to examine genetic predictors of treatment response in women living with obesity and BED. Secondary data analysis was conducted on a cross-sectional comparison of three groups of women enrolled in trial group treatment for BED: women living with obesity and BED (n = 72), obesity without BED (n = 27), and normal-weight without BED (n = 45).

RESULTS

There were no significant genotype × time interactions related to anthropometrics or binge frequency for any individual DA genotypes, or to the composite score reflecting DA availability. At baseline, there were no significant between-group differences in frequencies of DA-related alleles, nor were there associations between genotypes and anthropometrics.

CONCLUSIONS

Our study found no evidence to suggest that the DRD2/ANKK1 Taq1A, COMT, MAO-A, or DAT-1 polymorphisms are associated with response to behavioral intervention for BED as measured by changes in binge frequency. Future studies should examine a greater variety of dopaminergic polymorphisms, other candidate genes that target other neurotransmitter systems, as well as examine their impact on both behavioral and pharmacological-based treatment for BED.

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.

Breaking It Down: Investigation of Binge Eating Components in Animal Models to Enhance Translation

Binge eating (BE) is a core eating disorder behavior that is present across nearly all eating disorder diagnoses (e. g., bulimia nervosa, binge eating disorder, anorexia nervosa binge/purge subtype), and is also widely present in the general population. Despite the prevalence of BE, limited treatment options exist and there are often high rates of relapse after treatment. There is evidence showing that genetic factors contribute to the heritability of BE and support for biological contributions to BE. However, more work is needed to fully understand neurobiological mechanisms underlying BE. One approach to target this problem is to separate BE into its distinct clinical components that can be more easily modeled using pre-clinical approaches. To date, a variety of animal models for BE have been used in pre-clinical studies; but there have been challenges translating this work to human BE. Here, we review these pre-clinical approaches by breaking them down into three clinically-significant component parts (1) consumption of a large amount of food; (2) food consumption within a short period of time; and (3) loss of control over eating. We propose that this rubric identifies the most frequently used and effective ways to model components of BE behavior using pre-clinical approaches with the strongest clinical relevance. Finally, we discuss how current pre-clinical models have been integrated with techniques using targeted neurobiological approaches and propose ways to improve translation of pre-clinical work to human investigations of BE that could enhance our understanding of BE behavior.

The Binge Eating Genetics Initiative (BEGIN): study protocol

BACKGROUND

The Binge Eating Genetics Initiative (BEGIN) is a multipronged investigation examining the interplay of genomic, gut microbiota, and behavioral factors in bulimia nervosa and binge-eating disorder.

METHODS

1000 individuals who meet current diagnostic criteria for bulimia nervosa or binge-eating disorder are being recruited to collect saliva samples for genotyping, fecal sampling for microbiota characterization, and recording of 30 days of passive data and behavioral phenotyping related to eating disorders using the app Recovery Record adapted for the Apple Watch.

DISCUSSION

BEGIN examines the interplay of genomic, gut microbiota, and behavioral factors to explore etiology and develop predictors of risk, course of illness, and response to treatment in bulimia nervosa and binge-eating disorder. We will optimize the richness and longitudinal structure of deep passive and active phenotypic data to lay the foundation for a personalized precision medicine approach enabling just-in-time interventions that will allow individuals to disrupt eating disorder behaviors in real time before they occur.

TRIAL REGISTRATION

The ClinicalTrials.gov identifier is NCT04162574. November 14, 2019, Retrospectively Registered.

A proposed synergistic effect of CSF1R and NMUR2 variants contributes to binge eating in hereditary diffuse leukoencephalopathy with spheroids

Background

The genetic mechanisms of binge eating (BE) as a disease identity remain obscure. BE is usually viewed as a part of the behavioral variant of frontotemporal dementia (bvFTD) features. We encountered a family with hereditary diffuse leukoencephalopathy with spheroids (HDLS) that manifested uniformly with binge-eating-onset dementia. The genetic factors associated with the rare phenotype were investigated.

Methods

The detailed phenotypes of the patients were described. We performed whole-exome sequencing (WES) of family members and repeat-primed PCR to analyze the patients' expansion size of C9orf72, a well-established gene causing FTD. The WES results of additional HDLS patients without BE manifestations were also investigated.

Results

All affected individuals had a BE-dementia-epilepsy pattern of disease progression. A recurrent disease-causing mutation in CSF1R established the diagnosis of HDLS in the family. No abnormalities in the expansion size of C9orf72 were detected. The concurrence of a recurrent CSF1R mutation and a rare variant in NMUR2, a gene functionally related to BE, was revealed in the affected family members. No potentially pathogenic variants in other known BE-associated genes were identified. Both the NMUR2 variant and the CSF1R mutation cosegregated with the BE-dementia-epilepsy phenotype in the family. In three additional HDLS patients without BE, no pathogenic variants in NMUR2 were detected.

Conclusions

We propose that synergistic genetic effects of NMUR2 and CSF1R variants may exist and contribute to the development of the BE phenotype in HDLS. NMUR2 is one of the potential susceptible genes in BE and may contribute in a background of a disrupted structural neuronetwork. Further studies in other BE-related disorders are required.

Maternal Eating Disorders and Eating Disorder Treatment Among Girls in the Growing Up Today Study

PURPOSE

The aim of the study was to assess whether girls with mothers who have had an eating disorder (ED) have greater odds of developing ED symptoms and whether girls with ED symptoms have greater odds of receiving ED treatment if their mothers have an ED history.

METHODS

Data came from 3,649 females in the Growing Up Today Study. Data were collected via questionnaires that were mailed every 12-24 months from 1996 to 2013. Girls who reported on ED treatment in 2013 and whose mothers completed a questionnaire in 2004 about maternal and child EDs were included in main analyses. Generalized estimating equations were used.

RESULTS

Among complete cases, 28.3% of girls reported symptoms meeting criteria for an ED in at least 1 year and, of these, 12.4% reported receiving treatment. Girls with mothers with ED histories had nearly twice the odds of reporting symptoms of any ED (adjusted odds ratio: 1.89; 95% confidence interval: 1.38-2.60). Girls who reported symptoms meeting criteria for any ED had more than twice the odds of reporting treatment if their mother had an ED history (adjusted odds ratio: 2.23; 95% confidence interval: 1.25-3.99).

CONCLUSIONS

Girls with mothers with an ED history had greater odds of both reporting ED symptoms and receiving ED treatment. Screening both girls and their mothers for current or previous disordered eating may be important for the prevention and detection of ED symptoms. More research is needed to examine reasons for the association between maternal ED history and ED treatment in girls.

Clinical phenotype and genetic risk factors for bipolar disorder with binge eating: an update

Introduction: Clinical and genetic study of psychiatric conditions has underscored the co-occurrence of complex phenotypes and the need to refine them. Bipolar Disorder (BD) and Binge Eating (BE) behavior are common psychiatric conditions that have high heritability and high co-occurrence, such that at least one quarter of BD patients have BE (BD + BE). Genetic studies of BD alone and of BE alone suggest complex polygenic risk models, with many genetic risk loci yet to be identified. Areas covered: We review studies of the epidemiology of BD+BE, its clinical features (cognitive traits, psychiatric comorbidity, and role of obesity), genomic studies (of BD, eating disorders (ED) defined by BE, and BD + BE), and therapeutic implications of BD + BE. Expert opinion: Subphenotyping of complex psychiatric disorders reduces heterogeneity and increases statistical power and effect size; thus, it enhances our capacity to find missing genetic (and other) risk factors. BD + BE has a severe clinical picture and genetic studies suggests a distinct genetic architecture. Differential therapeutic interventions may be needed for patients with BD + BE compared with BD patients without BE. Recognizing the BD + BE subphenotype is an example of moving towards more precise clinical and genetic entities.

Genetics of Eating Disorders: What the Clinician Needs to Know

Anorexia nervosa (AN), bulimia nervosa (BN), and binge-eating disorder (BED) are heritable conditions that are influenced by both genetic and environmental factors. Recent genome-wide association studies (GWAS) of AN have identified specific genetic loci implicated in AN, and genetic correlations have implicated both psychiatric and metabolic factors in its origin. No GWAS have been performed for BN or BED. Genetic counseling is an important tool and can aid families and patients in understanding risk for these illnesses.

Role of eating disorders-related polymorphisms in obesity pathophysiology

Human biological system provides innumerable neuroendocrine inputs for food intake control, with effects on appetite's modulation and the satiety signs. Its regulation is very complex, engaging several molecular interactions with many tissues, hormones, and neural circuits. Thus, signaling molecules that control food intake are critical for normal energy homeostasis and a deregulation of these pathways can lead to eating disorders and obesity. In line of this, genetic factors have a significantly influence of the regulation of neural circuits controlling the appetite and satiety pathways, as well as the regulation of brain reward systems. Single Nucleotide Polymorphisms (SNPs) in genes related to hypothalamic appetite and satiety mechanisms, further in multiple neurotransmitter systems may contribute to the development of major Eating Disorders (EDs) related to obesity, among them Binge Eating Disorder (BED) and Bulimia Nervosa (BN), which are discussed in this review.

Genetic risk factors for eating disorders: an update and insights into pathophysiology

Genome-wide-association studies (GWASs), epigenetic, gene-expression and gene-gene interaction projects, nutritional genomics and investigations of the gut microbiota have increased our knowledge of the pathophysiology of eating disorders (EDs). However, compared with anorexia nervosa, genetic studies in patients with bulimia nervosa and binge-eating disorder are relatively scarce, with the exception of a few formal genetic and small-sized candidate-gene-association studies. In this article, we review important findings derived from formal and molecular genetics in order to outline a genetics-based pathophysiological model of EDs. This model takes into account environmental and nutritional factors, genetic factors related to the microbiome, the metabolic and endocrine system, the immune system, and the brain, in addition to phenotypical traits of EDs. Shortcomings and advantages of genetic research in EDs are discussed against the historical background, but also in light of potential future treatment options for patients with EDs.

Binge-Like Eating Is Not Influenced by the Murine Model of OPRM1 A118G Polymorphism

Impairments in opioid receptor signaling have been implicated in disordered eating. A functional variant of the OPRM1 gene is a guanine (G) substitution for adenine (A) at the 118 position of exon 1 (A118G). The influence of the A118G variant on binge eating behaviors and the effectiveness of pharmacotherapies used to treat binge eating have not been characterized. Mice were generated with A to G substitution at the 112 position on exon 1 to produce a murine equivalent of the human A118G variant. Homozygous female mice (AA or GG) were exposed to intermittent access to a highly palatable sweet-fat food with or without prior calorie deprivation to promote dietary-induced binge eating. There were no genotype-dependent differences in the dietary-induced binge eating. However, GG mice exposed to intermittent calorie restriction (Restrict) had higher body weights compared with GG mice exposed to intermittent sweet fat-food (Binge) and ad libitum feeding (Naive). Acute oral dosing of lisdexamfetamine (0.15, 0.5, and 1.5 mg/kg) or sibutramine (0.3, 1, and 3 mg/kg) did not produce genotype-dependent differences in binge-like eating. In addition, no genotype-dependent differences in binge-like eating were observed with chronic (14-day) dosing of lisdexamfetamine (1.5 mg/kg/day) or sibutramine (3 mg/kg/day). In the chronic dosing, body weights were higher in the GG Restrict compared with AA Restrict. Our findings suggest that the A112G polymorphism does not influence binge eating behaviors or pharmacotherapies for treating binge eating.

Validation of the Arabic version of the binge eating scale and correlates of binge eating disorder among a sample of the Lebanese population

OBJECTIVES

To test the psychometric properties of the Arabic version of the Binge Eating Scale (BES), a self-questionnaire assessing binge eating, in a sample of the Lebanese population. The secondary objective was to evaluate factors associated with binge eating.

METHODS

This cross-sectional study, conducted between January and May 2018, enrolled 811 adult participants from all districts of Lebanon. The BES was administered to study its psychometric properties. The sample was divided into two separate samples (405 for sample 1 and 406 for sample 2). An exploratory factor analysis was executed on Sample 1, followed by a confirmatory factor analysis on Sample 2 using the structure obtained in Sample 1. Three hierarchical stepwise linear regressions were conducted to assess factors associated with binge eating.

RESULTS

The factor analysis suggested a two-factor structure for the BES explaining a total of 41.4% of the variance. All items could be extracted from the list. The internal consistency of the measurement was adequate (Cronbach's alpha = 0.86). The confirmatory factor analysis revealed an adequate fit to the model with satisfactory Maximum Likelihood Chi-Square/Degrees of Freedom (χ²/df), Steiger-Lind RMSEA, Joreskog GFI, and AGFI. Higher BMI, depression, anxiety, emotional eating, greater body dissatisfaction, and more pressure from media to lose weight were associated with higher binge eating. Higher expressive suppression facet score was associated with lower binge eating.

CONCLUSION

The Arabic version of BES could be a useful tool for screening and assessing the binge eating behaviors in clinical practice and research. Also, being dissatisfied with one's body size, having a history of sexual abuse, family history of binge eating, increased depressive/anxiety symptoms, and lower self-esteem seem to be associated with higher BES scores.

Effects of fat mass and obesity-associated (FTO) gene polymorphisms on binge eating in women with binge-eating disorder: The moderating influence of attachment style

OBJECTIVES

The genetics of binge-eating disorder (BED) is an emerging topic and one candidate pathway, namely the fat mass and obesity-associated (FTO) gene, may be implicated because of its role in food reward sensitivity and self-regulation of eating. The aims of this study were to examine the independent effects of variants of FTO on binge frequency in women with and without BED and to examine the moderating role of interpersonal attachment in this association.

METHODS

Secondary data analysis was conducted on a cross-sectional comparison of three groups of women in a trial of group treatment for BED: BED with obesity (n = 73), BED without obesity (n = 55), and normal weight without BED (n = 50). Women were genotyped for five of the most common FTO single-nucleotide polymorphisms, rs9939609, rs8050136, rs3751812, rs1421085, and rs1121980, which have been related to body mass index and energy intake. Binge frequency (Eating Disorder Examination), body composition (bioelectric impedance), and attachment (Attachment Style Questionnaire) were assessed.

RESULTS

There were no significant between-group differences for frequencies of FTO alleles, nor were there any significant anthropometric associations. The FTO × attachment interaction was significant whereby, relative to a low-risk FTO genotype, individuals with a high-risk genotype for the SNP rs1421085 and high-avoidant attachment had higher mean binge frequency than those with high genetic risk but low-avoidant attachment (β = -7.96; t = -2.07; P = 0.042).

CONCLUSIONS

FTO genotypes associated with risk for obesity and loss of control of eating, specifically rs1421085, may interact with insecure attachment in a way that may exacerbate binge eating among women with BED.

[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.

Children of Parents with Eating Disorders

PURPOSE OF REVIEW

Our primary goal in this article is to review recent findings (from 2015 and on) concerning children of parents with eating disorders. This review addresses the question of whether the offspring of parents with past or present eating disorders have adverse outcomes. This update is timely and informative because recent research includes controlled studies and large cohort designs and earlier reviews relied on case report evidence.

RECENT FINDINGS

Despite substantial diversity in study design, sample size, and parental eating disorder definition, overall, existing research suggests that the children of parents with eating disorders exhibit compromised development: a greater risk of perinatal complications; a tendency toward extremes of growth at birth; greater problems in feeding and eating behaviors and greater incidence of eating disorder symptoms; more psychological and socioemotional difficulties; and more negative qualities to parent-child interactions. Data on children's cognitive outcomes is thus far inconsistent. Given the relatively high incidence of eating disorder history in individuals of childbearing age, research into its potential effects on children is necessary. However, the methodological shortcomings and a limited evidence base caution in drawing conclusions. Nevertheless, mental health services should address the possible problems that these children face and offer tailored programs.

Complete sequence of the ANKK1 gene in Mexican-Mestizo individuals with obesity, with or without binge eating disorder

BACKGROUND

The aim of this study was to investigate if Mexican-Mestizo individuals with obesity, with or without binge eating disorder (BED), exhibited mutations or other type of genetic variants in the sequence of ANKK1.

SUBJECTS AND METHODS

Fifty unrelated individuals (21-53 years of age) with obesity, of Mexican-Mestizo ethnic origin were included; 25 of them had BED and 25 presented obesity without BED. The diagnosis of BED was based on criteria proposed in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). Besides, we also analyzed 100 individuals with normal body mass index. DNA from blood leukocytes was amplified by the polymerase chain reaction and all exons of ANKK1 were sequenced.

RESULTS

After ANKK1 sequencing we did not find any mutations; however, we observed various polymorphisms. One polymorphism, rs4938013 in exon 2 showed an association with obesity, whilst rs1800497 (also known as Taq1A) in exon 8, showed an association with BED (P = 0.020). Remarkable, for this study, the number of individuals for both polymorphisms for and additive model was sufficient to derive strong statistical power (80%, with a P < 0.05).

CONCLUSIONS

To our knowledge, this constitutes the first report where the complete sequences of ANKK1 has been analyzed in individuals with obesity, with or without BED. No mutations were found; however, one polymorphism was associated with obesity, with or without BED, and another one was associated with BED.

Rigor and reproducibility in genetic research on eating disorders

OBJECTIVE

We explored both within-method and between-method rigor and reproducibility in the field of eating disorders genetics.

METHOD

We present critical evaluation and commentary on component methods of genetic research (family studies, twin studies, molecular genetic studies) and discuss both successful and unsuccessful efforts in the field.

RESULTS

Eating disorders genetics has had a number of robust results that converge across component methodologies. Familial aggregation of eating disorders, twin-based heritability estimates of eating disorders, and genome-wide association studies (GWAS) all point toward a substantial role for genetics in eating disorders etiology and support the premise that genes do not act alone. Candidate gene and linkage studies have been less informative historically.

DISCUSSION

The eating disorders field has entered the GWAS era with studies of anorexia nervosa. Continued growth of sample sizes is essential for rigorous discovery of actionable variation. Molecular genetic studies of bulimia nervosa, binge-eating disorder, and other eating disorders are virtually nonexistent and lag seriously behind other major psychiatric disorders. Expanded efforts are necessary to reveal the fundamental biology of eating disorders, inform clinical practice, and deliver new therapeutic targets.

Eating disorders: Insights from imaging and behavioral approaches to treatment

Understanding factors that contribute to eating disorders, which affect 13% of females, is critical to developing effective prevention and treatment programs. In this paper, we summarize results from prospective studies that identified factors predicting onset and persistence of eating disorders and core symptom dimensions. Next, implications for intervention targets for prevention, and treatment interventions from the risk- and maintenance-factor findings are discussed. Third, given that evidence suggests eating disorders are highly heritable, implying biological risk and maintenance factors for eating disorders, we offer working hypotheses about biological factors that might contribute to eating disorders, based on extant risk factor findings, theory, and cross-sectional studies. Finally, potentially fruitful directions for future research are presented. We suggest that it would be useful for experimental therapeutics trials to evaluate the effects of reducing the risk factors on future onset of eating pathology and on reducing maintenance factors on the risk for persistence of eating pathology, and encourage researchers to utilize prospective high-risk studies so that knowledge regarding potential intervention targets for prevention and treatment interventions for eating disorders can be advanced. Using the most rigorous research designs should help improve the efficacy of prevention and treatment interventions for eating disorders.

Children of parents with BED have more eating behavior disturbance than children of parents with obesity or healthy weight

OBJECTIVE

A limited literature suggests an association between parental eating disorders and child eating-disorder behaviors although this research has focused primarily on restrictive-type eating disorders and very little is known about families with binge-eating disorder (BED).

METHODS

The current study focused on parents (N = 331; 103 fathers and 226 mothers), comparing parents with core features of BED (n = 63) to parents with obesity and no eating disorder (OB; n = 85) and parents with healthy-weight and no eating disorder (HW; n = 183).

RESULTS

Parents with BED were significantly more likely than OB and HW parents to report child binge eating, and more likely than HW parents to report child overeating. Parents with BED felt greater responsibility for child feeding than OB parents, and felt more concern about their child's weight than OB and HW parents. Dietary restriction of the child by the parents was related to child binge eating, overeating, and child overweight, and parental group was related to child binge eating (parental BED), overeating (parental BED), and child weight (parental OB).

DISCUSSION

Parents with BED report greater disturbance in their children's eating than OB and HW parents, and OB parents report higher child weight than HW parents. This suggests that it is important to consider both eating-disorder psychopathology and obesity in clinical interventions and research. Our cross-sectional findings, which require experimental and prospective confirmations, provide preliminary evidence suggesting potential factors in families with parental BED and obesity to address in treatment and prevention efforts for pediatric eating disorders and obesity. © 2016 Wiley Periodicals, Inc.(Int J Eat Disord 2017; 50:648-656).

Incorporation of the time aspect into the liability-threshold model for case-control-family data

Familial aggregation and the role of genetic and environmental factors can be investigated through family studies analysed using the liability-threshold model. The liability-threshold model ignores the timing of events including the age of disease onset and right censoring, which can lead to estimates that are difficult to interpret and are potentially biased. We incorporate the time aspect into the liability-threshold model for case-control-family data following the same approach that has been applied in the twin setting. Thus, the data are considered as arising from a competing risks setting and inverse probability of censoring weights are used to adjust for right censoring. In the case-control-family setting, recognising the existence of competing events is highly relevant to the sampling of control probands. Because of the presence of multiple family members who may be censored at different ages, the estimation of inverse probability of censoring weights is not as straightforward as in the twin setting but requires consideration. We propose to employ a composite likelihood conditioning on proband status that markedly simplifies adjustment for right censoring. We assess the proposed approach using simulation studies and apply it in the analysis of two Danish register-based case-control-family studies: one on cancer diagnosed in childhood and adolescence, and one on early-onset breast cancer. Copyright © 2017 John Wiley & Sons, Ltd.

Eating Disorders and Epigenetics

Eating disorders (EDs) are characterized by intense preoccupation with shape and weight and maladaptive eating practices. The complex of symptoms that characterize EDs often arise through the activation of latent genetic potentials by environmental exposures, and epigenetic mechanisms are believed to link environmental exposures to gene expression. This chapter provides an overview of genetic factors acting in the etiology of EDs. It then provides a background to the hypothesis that epigenetic mechanisms link stresses such as obstetric complications and childhood abuse as well as effects of malnutrition to eating disorders (EDs). The chapter then summarizes the emerging body of literature on epigenetics and EDs-mainly studies on DNA methylation in samples of anorexia and bulimia. The available evidence base suggests that an epigenetically informed perspective contributes in valuable ways to the understanding of why people develop EDs.

Associations between neural correlates of visual stimulus processing and set-shifting in ill and recovered women with anorexia nervosa

Women ill with anorexia nervosa (AN) have been shown to exhibit altered cognitive functioning, particularly poor set-shifting (SS). In this study, we investigated whether brain activation in frontal and parietal regions during visual stimulus processing correlates with SS ability. Women currently ill with AN (AN; N=14), recovered women (REC; N=14) and healthy controls (HC; N=15), viewed alternating blocks of food and non-food pictures during functional magnetic resonance imaging (fMRI). The Berg's Card Sorting Task was completed outside the scanner to measure SS. A priori regions of interest (ROIs) were defined in frontal and parietal regions. The activation during visual stimulus processing in several ROIs correlated positively with poor SS ability in REC, particularly in the left dorsal anterior cingulate cortex (dACC). The correlations with poor SS ability were opposite in AN patients, particularly in the right dACC. These findings underscore that addressing heightened levels of cognitive control associated with higher frontal activation could reduce cognitive inflexibility in recovered women. In AN, greater activation in frontal and parietal regions might be necessary to perform at normal levels during various tasks. Thus, weight restoration could be necessary for AN patients prior to addressing cognitive inflexibility.

The role of habit in compulsivity

Compulsivity has been recently characterized as a manifestation of an imbalance between the brain׳s goal-directed and habit-learning systems. Habits are perhaps the most fundamental building block of animal learning, and it is therefore unsurprising that there are multiple ways in which the development and execution of habits can be promoted/discouraged. Delineating these neurocognitive routes may be critical to understanding if and how habits contribute to the many faces of compulsivity observed across a range of psychiatric disorders. In this review, we distinguish the contribution of excessive stimulus-response habit learning from that of deficient goal-directed control over action and response inhibition, and discuss the role of stress and anxiety as likely contributors to the transition from goal-directed action to habit. To this end, behavioural, pharmacological, neurobiological and clinical evidence are synthesised and a hypothesis is formulated to capture how habits fit into a model of compulsivity as a trans-diagnostic psychiatric trait.

The neurobiological basis of binge-eating disorder

Relatively little is known about the neuropathophysiology of binge-eating disorder (BED). Here, the evidence from neuroimaging, neurocognitive, genetics, and animal studies are reviewed to synthesize our current understanding of the pathophysiology of BED. Binge-eating disorder may be conceptualized as an impulsive/compulsive disorder, with altered reward sensitivity and food-related attentional biases. Neuroimaging studies suggest there are corticostriatal circuitry alterations in BED similar to those observed in substance abuse, including altered function of prefrontal, insular, and orbitofrontal cortices and the striatum. Human genetics and animal studies suggest that there are changes in neurotransmitter networks, including dopaminergic and opioidergic systems, associated with binge-eating behaviors. Overall, the current evidence suggests that BED may be related to maladaptation of the corticostriatal circuitry regulating motivation and impulse control similar to that found in other impulsive/compulsive disorders. Further studies are needed to understand the genetics of BED and how neurotransmitter activity and neurocircuitry function are altered in BED and how pharmacotherapies may influence these systems to reduce BED symptoms.

Characteristics of binge eating disorder in relation to diagnostic criteria

The objective of this review was to examine the evidentiary basis for binge eating disorder (BED) with reference to the Diagnostic and Statistical Manual of Mental Disorders - Fifth Edition (DSM-5) diagnostic criteria for BED. A PubMed search restricted to titles and abstracts of English-language reviews, meta-analyses, clinical trials, randomized controlled trials, journal articles, and letters using human participants was conducted on August 7, 2015, using keywords that included "binge eating disorder," DSM-5, DSM-IV, guilt, shame, embarrassment, quantity, psychological, behavior, and "shape and weight concerns." Of the 257 retrieved publications, 60 publications were considered relevant to discussions related to DSM-5 diagnostic criteria and were included in the current review, and 20 additional references were also included on the basis of the authors' knowledge and/or on a review of the reference lists from relevant articles obtained through the literature search. Evidence supports the duration/frequency criterion for BED and the primary importance of loss of control and marked distress in identifying individuals with BED. Although overvaluation of shape/weight is not a diagnostic criterion, its relationship to the severity of BED psychopathology may identify a unique subset of individuals with BED. Additionally, individuals with BED often exhibit a clinical profile consisting of psychiatric (eg, mood, obsessive-compulsive, and impulsive disorders) and medical (eg, gastrointestinal symptoms, metabolic syndrome, and type 2 diabetes) comorbidities and behavioral profiles (eg, overconsumption of calories outside of a binge eating episode and emotional eating). Future revisions of the BED diagnostic criteria should consider the inclusion of BED subtypes, perhaps based on the overvaluation of shape/weight, and an evidence-based reassessment of severity criteria.

[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.

Incidence and weight trajectories of binge eating disorder among young women in the community

OBJECTIVE

To assess the population prevalence and incidence of binge eating disorder (BED) among young women.

METHOD

In a nationwide longitudinal study of Finnish twins born 1975-1979, the women participated in five surveys from age 16 until their mid-thirties. At Wave 4 (mean age 24 years), the women (N = 2,825) underwent a 2-stage screening for eating disorders. We assessed the lifetime prevalence, incidence, and clinical characteristics of DSM-5 BED.

RESULTS

We detected 16 women who met DSM-5 criteria for BED, yielding a lifetime prevalence of 0.7% (95% confidence interval [CI] 0.4-1.2%). The incidence of BED among women between 10 and 24 years of age was 35 (95% CI 20-60) per 100,000 person-years. The mean age of onset of BED was 19 years (range 13-27 years). Of the cases, 13/16 (81%) were currently ill. Duration of illness at the time of assessment ranged from less than a year to 13 years (median 6 years). Of women with BED, only two had a history of other eating disorders, but six had lifetime major depressive disorder. Two-thirds of the women with BED belonged to the highest weight quartile at age 16, and their mean BMI at age 22-27 year was 26.2 kg/m(2) (range 22.1-32.5 kg/m(2)).

DISCUSSION

Incident BED as defined by DSM-5 was relatively rare among younger women and was often preceded by relative overweight. BED often occurred without a history of other eating disorders, but comorbidity with major depressive disorder was common.

The epidemiology and genetics of binge eating disorder (BED)

This narrative review provides an overview of the epidemiology of binge eating disorder (BED), highlighting the medical history of this disorder and its entry as an independent condition in the Feeding and Eating Disorders section of the recently published Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition. Estimates of prevalence are provided, as well as recognition that the female to male ratio is lower in BED than in other eating disorders. Evidence is also provided of the most common comorbidities of BED, including mood and anxiety disorders and a range of addiction disorders. In addition, discussion of the viewpoint that BED itself may be an addiction - at least in severe cases - is presented. Although the genetic study of BED is still in its infancy, current research is reviewed with a focus on certain neurotransmitter genes that regulate brain reward mechanisms. To date, a focal point of this research has been on the dopamine and the μ-opioid receptor genes. Preliminary evidence suggests that a predisposing risk factor for BED may be a heightened sensitivity to reward, which could manifest as a strong dopamine signal in the brain's striatal region. Caution is encouraged, however, in the interpretation of current findings, since samples are relatively small in much of the research. To date, no genome-wide association studies have focused exclusively on BED.

Diagnosing binge eating disorder in a primary care setting

Binge eating disorder (BED), now recognized as a distinct eating disorder in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, is the most prevalent eating disorder. Although nearly half of individuals with BED are obese, BED also occurs in nonobese individuals. Despite the relatively high percentage of weight loss treatment-seeking individuals meeting BED criteria, primary care physicians may not be familiar with or have ever diagnosed BED. Many providers may also have difficulty distinguishing BED as a contributory factor in obesity. This review differentiates BED from other causes of obesity by describing how obese individuals with BED differ from obese individuals without BED and from nonobese individuals with BED in areas including psychopathology, behavior, genetics, physiology, quality of life and productivity. The ways in which health-care providers can identify individuals who may have BED are also highlighted so the proper course of treatment is pursued. Overall, obese individuals with BED demonstrate a number of key characteristics that differentiate them from obese individuals without eating disorders, including increased impulsivity in response to food stimuli with loss of control over eating, resulting in the consumption of more calories. They also experience significant guilt and other negative emotions following a meal. In addition, individuals with BED patients have more psychiatric comorbidity, display more psychopathology, exhibit longer binge durations, consume more meals as snacks during the day and have less dietary restraint compared with individuals with BED who are not obese. However, the differences between individuals with BED who are obese versus not obese are not as prominent. Taken together, the evidence appears to support the conclusion that BED is a unique and treatable neurobehavioral disorder associated with distinct behavioral and psychological profiles and distinct medical and functional outcomes, and that it is not merely a subtype of obesity.

Genetics and genomics of psychiatric disease

Large-scale genomic investigations have just begun to illuminate the molecular genetic contributions to major psychiatric illnesses, ranging from small-effect-size common variants to larger-effect-size rare mutations. The findings provide causal anchors from which to understand their neurobiological basis. Although these studies represent enormous success, they highlight major challenges reflected in the heterogeneity and polygenicity of all of these conditions and the difficulty of connecting multiple levels of molecular, cellular, and circuit functions to complex human behavior. Nevertheless, these advances place us on the threshold of a new frontier in the pathophysiological understanding, diagnosis, and treatment of psychiatric disease.

Optimum study design for detecting imprinting and maternal effects based on partial likelihood

Despite spectacular advances in molecular genomic technologies in the past two decades, resources available for genomic studies are still finite and limited, especially for family-based studies. Hence, it is important to consider an optimum study design to maximally utilize limited resources to increase statistical power in family-based studies. A particular question of interest is whether it is more profitable to genotype siblings of probands or to recruit more independent families. Numerous studies have attempted to address this study design issue for simultaneous detection of imprinting and maternal effects, two important epigenetic factors for studying complex diseases. The question is far from settled, however, mainly due to the fact that results and recommendations in the literature are based on anecdotal evidence from limited simulation studies rather than based on rigorous statistical analysis. In this article, we propose a systematic approach to study various designs based on a partial likelihood formulation. We derive the asymptotic properties and obtain formulas for computing the information contents of study designs being considered. Our results show that, for a common disease, recruiting additional siblings is beneficial because both affected and unaffected individuals will be included. However, if a disease is rare, then any additional siblings recruited are most likely to be unaffected, thus contributing little additional information; in such cases, additional families will be a better choice with a fixed amount of resources. Our work thus offers a practical strategy for investigators to select the optimum study design within a case-control family scheme before data collection.

Are obesity risk genes associated with binge eating in adolescence?

OBJECTIVE

Cognitions and behaviors characteristic of binge eating are associated with a polymorphism in the FTO gene, robustly related to body mass index (BMI) and obesity risk. We investigated the association between binge eating and the individual and combined effect of 32 SNPs robustly associated with BMI in a population-based sample. We hypothesized that higher BMI and binge eating might share a common genetic etiology.

METHODS

Binge eating was assessed in adolescents from the Avon Longitudinal Study of Parents and Children at age 14 (n = 5,958) and 16 years (n = 4,948). We tested associations between 32 BMI-related SNPs and binge eating in crude and BMI-, age-, and gender-adjusted regression models.

RESULTS

Crude analyses showed an association between binge eating and rs1558902 (FTO) that persisted after adjustment for BMI (OR = 1.20, P = 8 × 10(-3) ). A weighted allelic score consisting of all 32 BMI-related SNPs was associated with binge eating (P = 8 × 10(-4) ); this association attenuated (P = 0.08) when rs1558902 was removed from the weighted allelic score.

CONCLUSIONS

BMI-related genes are associated with adolescent binge eating, in particular an FTO polymorphism. Although replication is needed, our findings have biological plausibility and are consistent with a postulated effect of FTO on appetite and food intake. Future studies should aim to understand the mechanisms underlying the relationship between FTO, binge eating, and obesity.

Parental Characteristics Associated With Outcomes in Youth With Type 2 Diabetes: Results From the TODAY Clinical Trial

OBJECTIVE

This study examined parental factors associated with outcomes of youth in the Treatment Options for type 2 Diabetes in Adolescents and Youth (TODAY) clinical trial.

RESEARCH DESIGN AND METHODS

Of 699 youth with type 2 diabetes in the TODAY cohort, 623 (89.1%) had a parent participate and provide data at baseline, including weight, HbA1c, blood pressure, symptoms of depression, binge eating (BE), and medical history. Youth were followed 2-6.5 years. Data were analyzed using regression models and survival curve methods.

RESULTS

Parental diabetes (43.6% of parents) was associated with higher baseline HbA1c (P < 0.0001) and failure of youths to maintain glycemic control on study treatment (53.6% vs. 38.2% failure rate among those without a diabetic parent, P = 0.0002). Parental hypertension (40.6% of parents) was associated with hypertension in youth during TODAY (40.4% vs. 27.4% of youth with and without parental hypertension had hypertension, P = 0.0008) and with higher youth baseline BMI z scores (P = 0.0038). Parents had a mean baseline BMI of 33.6 kg/m(2). Parental obesity (BMI >30 kg/m(2)) was associated with higher baseline BMI z scores in the youth (P < 0.0001). Depressive symptoms in parents (20.6% of parents) were related to youth depressive symptoms at baseline only (P = 0.0430); subclinical BE in parents was related to the presence of subclinical BE (P = 0.0354) and depressive symptoms (P = 0.0326) in youth throughout the study period.

CONCLUSIONS

Parental diabetes and hypertension were associated with lack of glycemic control, hypertension, and higher BMI z scores in youth. Further research is needed to better understand and address parental biological and behavioral factors to improve youth health outcomes.

Genetics and Epigenetics of Eating Disorders

Eating disorders (EDs) are serious psychiatric conditions influenced by biological, psychological, and sociocultural factors. A better understanding of the genetics of these complex traits and the development of more sophisticated molecular biology tools have advanced our understanding of the etiology of EDs. The aim of this review is to critically evaluate the literature on the genetic research conducted on three major EDs: anorexia nervosa (AN), bulimia nervosa (BN), and binge eating disorder (BED). We will first review the diagnostic criteria, clinical features, prevalence, and prognosis of AN, BN, and BED, followed by a review of family, twin, and adoption studies. We then review the history of genetic studies of EDs covering linkage analysis, candidate gene association studies, genome-wide association studies, and the study of rare variants in EDs. Our review also incorporates a translational perspective by covering animal models of ED-related phenotypes. Finally, we review the nascent field of epigenetics of EDs and a look forward to future directions for ED genetic research.