Twin studies and the etiology of eating disorders

A Retrospective Literature Review of Eating Disorder Research (1990–2021): Application of Bibliometrics and Topical Trends

Despite the growing importance of eating disorders in society and academic literature, only a few bibliometric review studies using bibliometric analysis were available. Hence, this study aimed to explore and uncover hidden research topics and patterns in articles in terms of eating disorders over the last 30 years. In total, 4111 articles on eating disorders were analyzed using bibliometrics, network analyses, and structural topic modeling as the basis of mixed methods. In addition to general statistics about the journal, several key research topics, such as eating disorder (ED) treatment, ED symptoms, factors triggering ED, family related factors, eating behaviors, and social factors, were found based on topic correlations. This study found the key research variables that are frequently studied with EDs, such as AN, BN, BED, and ARFID. This study may help clinicians comprehend important risk factors associated with EDs. Moreover, the findings about key ED research topics and their association can be helpful for future studies to construct a comprehensive ED research framework. To our knowledge, this is the first study to use topic modeling in an academic journal on EDs and examine the diversity in ED research over 30 years of published research.

Risk factors for anorexia nervosa and bulimia nervosa in Japan and compared to a U.S. sample

OBJECTIVE

This study provides the first systematic investigation of environmental exposure to putative psychosocial risk factors for eating disorders in individuals with AN and BN in Japan. It also provides a comparison of risk factors for the development of AN and BN in Japan versus the United States.

METHOD

Participants in Japan were 96 women with a current DSM-IV AN or BN primary diagnosis (AN, n = 60; BN, n = 36) and 57 women with no current psychiatric diagnosis (NC group). Participants in the United States were 137 women with a current DSM-IV AN or BN primary diagnosis (AN-U.S., n = 71; BN-U.S., n = 66). A standardized semi-structured interview retrospectively assessed exposure to risk factors prior to first symptom onset, which were analyzed using General Linear Model analyses.

RESULTS

Perfectionism and negative affectivity, family relationship issues, and, to a lesser degree, parental psychopathology predicted the emergence of AN and BN in Japan. Physical and sexual abuse and family eating and weight concerns were not significant risk factors in Japan. Compared to their respective diagnostic U.S. groups, the Japanese AN group reported higher levels of individual mental health factors and lower levels of family dieting and family overweight, and the Japanese BN group reported higher levels on individual mental health factors, lower exposure to problems with their parents, and lower exposure to family weight and eating concerns.

DISCUSSION

These country-specific data from Japan contribute to an increasingly nuanced and global understanding of risk factors for eating disorders.

Anorexia Nervosa, Theory and Treatment: Where Are We 35 Years on from Hilde Bruch's Foundation Lecture?

Hilde Bruch's foundation lecture in 1982 is a milestone from which to survey current theory and treatment for anorexia nervosa. Bruch described problems in body perception, emotion processing and interpersonal relationships as core theoretical aspects of the illness and built her theory of psychopathology on these aspects, as well as on animal studies on attachment. She also noted that many psychological problems result as consequence of starvation. In the first part of this paper, we parse Bruch's clinical descriptions into elements of psychopathology (disturbances in body perception, attachment, emotion expression, perception and regulation, social comparison, interpersonal, and family and therapeutic relationships), in order to assemble and update the theoretical evidence for a model of the illness. In the second part, we describe and extend her description of three core targets of treatment: family relationships, patient's inner confusion and nutritional restoration. Copyright © 2017 John Wiley & Sons, Ltd and Eating Disorders Association.

A Comparison of Personality, Life Events, Comorbidity, and Health in Monozygotic Twins Discordant for Anorexia Nervosa

Genetic and environmental factors contribute to the etiology of anorexia nervosa (AN). The co-twin control design is one of the most powerful methods available to evaluate environmental factors that could contribute to differences between monozygotic (MZ) twins who are discordant for AN. Using available data from a unique and rare sample of 22 Swedish female MZ pairs discordant for AN, we compared personality, life events, comorbidity, and health factors. Twins with AN had significantly higher perfectionism scores than unaffected co-twins and reported younger ages at first diet than unaffected co-twins who had dieted. Consistent with previous literature, more twins with AN reported gastrointestinal problems than unaffected co-twins. Although not significant due to low statistical power, more unaffected co-twins reported experiencing emotional neglect than twins with AN. Early dieting may be a harbinger of the development of AN or an early symptom. Higher perfectionism may represent a risk factor, sequela, or both. Sibling perception of neglect is noteworthy given the impact of an ill child with AN on family function and wellbeing. The health and wellbeing of siblings should be addressed clinically when one child in the family suffers from AN.

Practice parameter for the assessment and treatment of children and adolescents with eating disorders

This Practice Parameter reviews evidence-based practices for the evaluation and treatment of eating disorders in children and adolescents. Where empirical support is limited, clinical consensus opinion is used to supplement systematic data review. The Parameter focuses on the phenomenology of eating disorders, comorbidity of eating disorders with other psychiatric and medical disorders, and treatment in children and adolescents. Because the database related to eating disorders in younger patients is limited, relevant literature drawn from adult studies is included in the discussion.

Eating habits, physical activity, consumption of substances and eating disorders in adolescents

The aim of this study was to evaluate the differences between adolescents with a high or low risk of developing an eating disorder (ED) in different health behaviors (eating habits, physical activity and the consumption of substances) per gender. The EAT-40 and the Inventory of Behavioral Health in Scholars were applied to 2142 middle school students from Alicante (Spain), of whom 52.8% were girls and 47.2% were boys, with an average age of 13.92 years old (Sd = 1.34). Results indicated that girls with a high risk of developing an ED consumed fewer meals, ate fewer unhealthy foods, followed more diets and paid more attention to nutritional components. Furthermore, they also performed more physical activity with the objective of losing weight, and consumed more tobacco, alcohol and medicines. Boys at high risk of developing an ED followed more diets and paid more attention to nutritional components. For boys, no more differences were found. These results suggest that any program directed at the prevention of ED should not only include nutritional education, but should also seek to promote regular physical activity with objectives other than weight loss or the burning of calories.

Refeeding syndrome influences outcome of anorexia nervosa patients in intensive care unit: an observational study

Introduction

Data on the epidemiology and management of anorexia nervosa (AN) in the intensive care unit (ICU) are scarce. The aim of this study was to evaluate the prevalence and associated morbidity and mortality of AN in French ICUs.

Methods

We randomly selected 30 ICUs throughout France. Thereafter, we retrospectively analyzed all patients with AN admitted to any of these 30 ICUs between May 2006 and May 2008. We considered demographic data, diagnosis at admission and complications occurring during the stay, focusing on refeeding syndrome and management of refeeding.

Results

Eleven of the 30 ICUs participated in the retrospective study, featuring 68 patients, including 62 women. Average body mass index at the admission was 12 ± 3 kg/m2. Twenty one were mechanically ventilated, mainly for neurological reasons. The reported average calorie intake was 22.3 ± 13 kcal/kg/24 h. Major diagnoses at admission were metabolic problems, refeeding survey and voluntary drug intoxication and infection. The most common complications were metabolic, hematological, hepatic, and infectious events, of which 10% occurred during refeeding. Seven patients developed refeeding syndrome. At day one, the average calorie intake was higher for patients who developed refeeding syndrome (23.2 ± 5 Kcal/kg/j; n = 7) versus patients without refeeding syndrome (14.1 ± 3 Kcal/kg/j; n = 61) P = 0.02. Seven patients died, two from acute respiratory distress syndrome and five from multiorgan-failure associated with major hydroelectrolytic problems.

Conclusions

The frequency of AN in ICU patients is very low and the crude mortality in this group is about 10%. Prevention and early-detection of refeeding syndrome is the key point.

Evidence of complex involvement of serotonergic genes with restrictive and binge purge subtypes of anorexia nervosa

OBJECTIVES

There is mixed evidence of association of serotoninergic genes with anorexia nervosa (AN), but substantial evidence for the involvement of serotonergic mechanisms in appetite control. This study was designed to investigate possible associations between the two subtypes of AN (Restricting-RAN, and Binge-purging-BPAN) and polymorphisms within five genes encoding for proteins involved in the serotoninergic system.

METHODS

In order to carry out this investigation we have conducted a case-control association study on 226 females meeting the criteria for AN, and 678 matched healthy females.

RESULTS

Our data show a significant association between polymorphisms with the gene encoding HTR2A with both AN subtypes, an association between polymorphisms within the genes encoding HTR1D and HTR1B with RAN, and an association between polymorphisms within the gene encoding HTR2C with BPAN. No associations were found for any polymorphisms of the serotonin transporter gene. This outcome indicates a substantial and complex inter-relationship between serotoninergic genes and AN.

CONCLUSIONS

Given these data we hypothesis that the expression or control of expression of several genes of the serotoninergic system, and interactions between these genes, could exert considerable influence over the specific symptomatology of the subtypes of AN.

A twin study of specific bulimia nervosa symptoms

BACKGROUND

Twin studies have suggested that additive genetic factors significantly contribute to liability to bulimia nervosa (BN). However, the diagnostic criteria for BN remain controversial. In this study, an item-factor model was used to examine the BN diagnostic criteria and the genetic and environmental contributions to BN in a population-based twin sample. The validity of the equal environment assumption (EEA) for BN was also tested.

METHOD

Participants were 1024 female twins (MZ n=614, DZ n=410) from the population-based Mid-Atlantic Twin Registry. BN was assessed using symptom-level (self-report) items consistent with DSM-IV and ICD-10 diagnostic criteria. Items assessing BN were included in an item-factor model. The EEA was measured by items assessing similarity of childhood and adolescent environment, which have demonstrated construct validity. Scores on the EEA factor were used to specify the degree to which twins shared environmental experiences in this model.

RESULTS

The EEA was not violated for BN. Modeling results indicated that the majority of the variance in BN was due to additive genetic factors. There was substantial variability in additive genetic and environmental contributions to specific BN symptoms. Most notably, vomiting was very strongly influenced by additive genetic factors, while other symptoms were much less heritable, including the influence of weight on self-evaluation. These results highlight the importance of assessing eating disorders at the symptom level.

CONCLUSIONS

Refinement of eating disorder phenotypes could ultimately lead to improvements in treatment and targeted prevention, by clarifying sources of variation for specific components of symptomatology.

Genetic and environmental influences on disordered eating: An adoption study

Twin studies indicate significant genetic, but little shared environmental, influences on eating disorders. However, critics argue that study limitations constrain the conclusions that can be drawn. Adoption studies avoid many of these limitations, but to date, no adoption studies of eating pathology have been conducted. The current study was the first adoption study to examine genetic/environmental effects for disordered eating. Participants included 123 adopted and 56 biological female sibling pairs. Disordered eating (i.e., overall eating pathology, body dissatisfaction, weight preoccupation, binge eating) was assessed with the Minnesota Eating Behaviors Survey (Klump, McGue, & Iacono, 2000; von Ranson, Klump, Iacono, & McGue, 2005). Biometric model fitting indicated significant genetic influences (59%-82%) on all forms of disordered eating, with nonshared environmental factors accounting for the remaining variance. Shared environmental factors did not contribute significantly to any disordered eating symptom. Our findings bolster those from twin studies and provide critical evidence of significant genetic effects on disordered eating symptoms.

Anorexia nervosa in identical triplets

The cause of anorexia nervosa (AN) is unclear, but is likely multifactorial, including psychological, familial, environmental, societal, genetic, and other biological factors. This case report of identical 12-year-old female triplets simultaneously concordant for AN illustrates the importance of addressing all these components in evaluation and treatment, and the difficulty of determining the relative importance of each factor in the cause of an individual's eating disorder. An overly close relationship and competitiveness between the girls, treated at times as a triplet group rather than as individuals, as well as stressful family dynamics, were probably important antecedents to the girls' AN. The girls encouraged each other and competed to lose weight. Brief individual and family psychotherapy, parent counseling, nutritional counseling, and psychoeducation led to successful treatment. The triplets were encouraged in treatment to compete with and encourage each other to obtain treatment goals, including eating more healthily and achieving healthy weights. A literature review of AN twins studies is also presented, as these studies add to our understanding of the relative importance of shared genes and shared environment in the development of AN. These studies also add insight into treating individuals from families with multiple affected relatives.

Further evidence of association of OPRD1 & HTR1D polymorphisms with susceptibility to anorexia nervosa

BACKGROUND

A recent study reported strong evidence for the involvement of a region on human chromosome 1 and genetic susceptibility to anorexia nervosa (AN). A more detailed analysis of this region has suggested 2 genes that may account for this susceptibility. These data suggest that polymorphisms in both the serotonin 1D (HTR1D) and opioid delta 1 (OPRD1) receptor genes show a significant association with restricting AN (RAN).

METHODS

In the current study, we have conducted an independent association study on 226 females meeting DSM-IV criteria for AN and 678 matched volunteers.

RESULTS

We genotyped 4 SNPs in HTR1D and 6 SNPs in OPRD1. 3 SNPs were found to be associated with both RAN and binge-purge AN (BPAN) within the gene for OPRD1. We also found evidence of association between 2 polymorphisms within HTR1D and RAN.

CONCLUSIONS

These data support the hypothesis that polymorphisms within this region form a component of the genetic basis to susceptibility to RAN. However, further work is required to understand the processes that may be mediated by these genes.

Genetics of food intake and eating behavior phenotypes in humans

This review summarizes the research advances of the past decade regarding the role of human genetic differences in energy and nutrient intake as well as in eating behavior phenotypes and selected eating disorders. The evidence for familial aggregation and heritability based on twin and nuclear family study designs is summarized. Genome-wide linkage scans and quantitative trait loci identified to date are discussed. DNA sequence variants in candidate genes are reviewed. Single genes associated with classical eating disorders are also incorporated. Epigenetic events will need to be incorporated in future studies designed to investigate the effects of DNA variants on dietary phenotypes. Understanding the relative contribution of global genetic variation and of DNA sequence variants in specific genes is important in the effort to influence dietary habits in a healthier direction.

Is an integral nutritional approach to eating disorders feasible in primary care?

Patients with eating disorders (ED) show alterations in both their behaviour and their intake of food, frequently presenting nutritional and somatic affectations. Besides the classical forms such as anorexia or bulimia nervosa, there has recently been an increase in atypical or incomplete forms of ED, such as binge eating. Primary care (PC) services form the central and closest nucleus of health care for the individual and the family, where ED occur and leave their mark. This allows PC to provide an integral response at all levels of care for ED. Primary prevention at school, in the family and community is fundamental to avoiding its inception. Secondary prevention is based on early diagnosis and treatment of ED and favours a better prognosis of the illness. Tertiary prevention tries to reduce the serious consequences with rehabilitation measures to alleviate complications and avoid risk to life. Due to its complexity, these patients are afforded the attention of multidisciplinary teams of specialists with experience in treating this condition. In consultation with the team, the general practitioner should adopt a leading role at all levels of attention, as he/she is the link between the team, the family and the patient. This requires both regulated, specific training in the disease and the allocation of resources to carry it through. Putting into practice all these plans would allow us to give a positive answer to the question posed in the title of the present article.

Essstörungen und Adipositas im Kindes- und Jugendalter

Zusammenfassung. Essstörungen und Adipositas stellen auch und gerade im Kindes- und Jugendalter ein ernst zu nehmendes Gesundheitsproblem dar. In diesem Beitrag werden die Erscheinungsformen von Essstörungen und Adipositas bei Kindern und Jugendlichen, epidemiologische Befunde, Risikofaktoren und Entstehungsbedingungen sowie aktuelle Befunde zu psychologischen Interventions- und Präventionsmöglichkeiten vorgestellt.

Association between childhood feeding problems and maternal eating disorder: role of the family environment

BACKGROUND

There is a strong relationship between feeding problems in childhood and eating disorder in the mother. The mechanisms responsible for this relationship are not understood.

AIMS

To elucidate family-environmental factors that could mediate this association.

METHOD

A general population sample of children with feeding problems (n=35), other problems (shyness, fears or behavioural problems; n=58), or no problems (n=23) was identified. The mental state of their mothers was evaluated, including an assessment of current and past eating disorder. Video recordings were made in the families' homes of a mealtime and of the mothers and children participating in a standardised exploratory task.

RESULTS

Two family-environmental variables significantly distinguished the children with feeding problems from the other two groups: 'mealtime disorganisation' and 'maternal strong control and disharmony'. Path analysis revealed the importance of these two environmental variables in mediating the association between child and maternal disturbance.

CONCLUSIONS

The degree of mealtime disorganisation and the level of maternal strong control and disharmony mediate the association between maternal eating disorder and child feeding disturbance.

Coming to Terms With Risk Factors for Eating Disorders: Application of Risk Terminology and Suggestions for a General Taxonomy

The aims of the present review are to apply a recent risk factor approach (H. C. Kraemer et al., 1997) to putative risk factors for eating disorders, to order these along a timeline, and to deduce general taxonomic questions. Putative risk factors were classified according to risk factor type, outcome (anorexia nervosa, bulimia nervosa, binge-eating disorder, full vs. partial syndromes), and additional factor characteristics (specificity, potency, need for replication). Few of the putative risk factors were reported to precede the onset of the disorder. Many factors were general risk factors; only few differentiated between the 3 eating disorder syndromes. Common risk factors from longitudinal and cross-sectional studies were gender, ethnicity, early childhood eating and gastrointestinal problems, elevated weight and shape concerns, negative self-evaluation, sexual abuse and other adverse experiences, and general psychiatric morbidity. Suggestions are made for the conceptualization of future risk factor studies.

Causes and recovery in anorexia nervosa: the patient's perspective

OBJECTIVE

We explored anorexic patients' subjective accounts of the causes of their anorexia and of the factors that fostered recovery. Subjective accounts could assist in understanding this complicated and often intractable disorder.

METHOD

All female new referrals to an eating disorders service underwent extensive interviews including open-ended questions about their beliefs concerning the causes of their anorexia nervosa and factors that led to recovery. Responses were categorized by two independent raters.

RESULTS

The most commonly mentioned perceived causes were dysfunctional families, weight loss and dieting, and stressful experiences and perceived pressure. The three most commonly cited factors contributing to recovery were supportive nonfamilial relationships, therapy, and maturation.

DISCUSSION

Individuals with anorexia nervosa perceive both external (family environment) and personal factors (dieting and stress) as contributory to their disorders. The results underscore the importance of interpersonal factors in recovery from anorexia nervosa and suggest that attention to this area in treatment may be beneficial.

Family therapy for identical twins with anorexia nervosa

The rarity of identical twins with anorexia nervosa (AN) makes formulating an effective treatment approach for this subset of individuals quite difficult Clinicians may be applying treatment strategies that have been designed for individuals with an eating disorder. However, these approaches might have to be modified for the treatment of identical twins. The few available case studies have not discussed the challenges a clinician faces when treating identical twins with AN. In this report we describe the presentation of the case of adolescent monozygotic twins who were simultaneously concordant for AN. We discuss their unique presentation and our approach to their treatment.

Eating disorders

Eating disorders are an important cause of physical and psychosocial morbidity in adolescent girls and young adult women. They are much less frequent in men. Eating disorders are divided into three diagnostic categories: anorexia nervosa, bulimia nervosa, and the atypical eating disorders. However, the disorders have many features in common and patients frequently move between them, so for the purposes of this Seminar we have adopted a transdiagnostic perspective. The cause of eating disorders is complex and badly understood. There is a genetic predisposition, and certain specific environmental risk factors have been implicated. Research into treatment has focused on bulimia nervosa, and evidence-based management of this disorder is possible. A specific form of cognitive behaviour therapy is the most effective treatment, although few patients seem to receive it in practice. Treatment of anorexia nervosa and atypical eating disorders has received remarkably little research attention.

Psychiatric comorbidity in anorexia and bulimia nervosa: nature, prevalence, and causal relationships

Eating disorders are complex, multifactorially determined phenomena. When individuals with eating disorders present for treatment with comorbid conditions, case conceptualization is further complicated and, as a result, it may be difficult to determine optimal psychological or pharmacological treatment. This article reviews the evidence of the association between eating disorders (anorexia nervosa [AN] and bulimia nervosa [BN]) and Axis I depression, obsessive-compulsive disorder (OCD), substance abuse, and Axis II personality disorders, for the purposes of increasing awareness about the different options for case conceptualization. Although other diagnoses comorbid with eating disorders are of interest to clinicians (e.g., posttraumatic stress disorder [PTSD] and social phobia), their comprehensive review is currently premature due to a lack of empirical scrutiny. Finally, future directions for research, including suggestions for the use of particular assessment tools and more sophisticated research designs, are discussed.

Individual psychotherapy in the outpatient treatment of adults with anorexia nervosa

BACKGROUND

Anorexia nervosa is a disorder of high morbidity and significant mortality. It is commonest in young adult women, in whom the incidence may be increasing. The focus of treatment has moved to an outpatient setting and a number of differing psychotherapies are presently used in treatment.

OBJECTIVES

The aim of the present review was to evaluate the evidence from randomised controlled trials for the efficacy of outpatient psychotherapies used in the treatment of older adolescents and adults with anorexia nervosa

SEARCH STRATEGY

The strategy comprised database searches of MEDLINE, EXTRAMED, EMBASE,PSYCLIT, CURRENT CONTENTS, Cochrane Collaboration Controlled Trials Register and the Depression and Anxiety Neuroses Cochrane Group (CCDAN), a hand-search of The International Journal of Eating Disorders, and he reference lists of all papers selected. Personal letters were sent to identified notable researchers published in the area, requesting information on trials that are unpublished or in progress.

SELECTION CRITERIA

All randomised controlled trials of adult individual outpatient therapy for anorexia nervosa as defined by the DSM-IV or similar international criterion. Quality ratings were made according to the CCDAN criteria and in addition, whether the trial had examined treatment integrity.

DATA COLLECTION AND ANALYSIS

A range of outcome variables were selected, including physical state, severity of eating disorder attitudes and beliefs, interpersonal function, and general psychiatric symptom severity. Continuous outcome data comparisons were made with the standardized mean difference statistic, and binary outcome comparisons made with the relative risk statistic. Reliability of data extraction and quality ratings were made with the kappa statistic. Sensitivity analyses to evaluate the effects of trial quality and subgroup analyses to explore specific questions of treatment effects from different settings, frequency and duration of therapies were planned.

MAIN RESULTS

Six small trials only, two of which included children or adolescents, were identified from the search and aggregation of data was not possible. Bias was possible due particularly to lack of blinding of outcome assessments. The results in two trials suggested that 'treatment as usual' or similar may be less efficacious than a specific psychotherapy. No specific treatment was consistently superior to any other specific approach. Dietary advice as a control arm had a 100% non-completion rate in one trial.

REVIEWER'S CONCLUSIONS

No specific approach can be recommended from this review. It is unclear why 'treatment as usual' performed so poorly or why dietary advice alone appeared so unacceptable as the reasons for non-completion were not reported. There is an urgent need for large well-designed trials in his area.

Pattern of birth in anorexia nervosa. I: Early-onset cases in the United Kingdom

OBJECTIVES

Previous studies suggest that adults with anorexia nervosa are more likely to be born in spring and early summer. This study examines whether this pattern of birth is true of early-onset anorexia nervosa, and whether there is a relationship between environmental temperature at assumed time of conception and a later diagnosis of anorexia nervosa.

METHOD

The population were children and adolescents with diagnoses of anorexia nervosa (N = 259) or "other eating disorders" (N = 149). Distribution of births across the year was compared between groups and relative to standard population norms. Temperature at assumed time of conception was taken from meteorological records.

RESULTS

There was a significant preponderance of births among those with anorexia nervosa between April and June, compared with the other months of the year and with the "other eating disorders" group. Anorexia nervosa was also associated with higher environmental temperature at assumed time of conception.

CONCLUSIONS

Among early-onset cases in the United Kingdom, patients with anorexia nervosa are more likely to be born between April and June, and to be conceived during warmer months. A tentative "temperature at conception" hypothesis is advanced to explain these findings and to generate further research.

The human genetics of eating disorders lessons from the leptin/melanocortin system

Genetic analysis of eating disorders is complex phenotypically and genotypically. As seen in the leptin/melanocortin system, however, the results can lead to a deeper understanding and to new therapies. Benefits are expected for eating disorders that stem from genetic and psychologic causes. Finally, an awareness of possible genetic causes of eating disorders will help determine the causes--and thus the treatments--in children and adolescents with eating disorders, as exemplified by obese patients with mutations in the POMC, PC1, leptin, and MC4R loci.

The children of mothers with eating disorders

There is good evidence that children of parents with psychological disorders are themselves at increased risk of disturbances in their development. Although there has been considerable research on a variety of disorders such as depression and alcohol, research on the children of parents with eating disorders has been relatively recent. This paper aims to review the evidence and covers a number of areas, including genetic factors, pregnancy, the perinatal and postpartum period, infancy, and the early years of life, focusing on feeding and mealtimes, general parenting functions, and growth. This is followed by a consideration of psychopathology in the children, parental attitudes to children's weight and shape, and adolescence. What is clear is that although there are numerous case reports and case series, the number of systematic controlled studies is relatively small, and almost nothing has been written about the children of fathers with eating disorders. What is evident from the available evidence is that children of mothers with eating disorders are at increased risk of disturbance, but that the risk depends on a variety of factors, and that difficulties in the children are far from invariable. The paper concludes by summarizing five broad categories of putative mechanisms, based on the evidence to date, by which eating disturbance in parents can influence child development.

Anorexia nervosa: manifestations and management for the gastroenterologist

Anorexia nervosa is a complex psychiatric disorder with significant morbidity and mortality. It is important for gastroenterologists to be aware of the physiological effects and potential complications of anorexia nervosa, as they are frequently involved in treating patients with this disorder. We review the classic, GI, and neuroendocrinological features of anorexia nervosa. We also discuss gender differences and treatment options in anorexia nervosa. Further studies of GI physiology and pharmacology are needed to determine whether any disturbances may be amenable to therapeutic intervention. Future treatments directed at improving GI sensorimotor function and neurohormonal abnormalities in patients with anorexia nervosa may impact their nutritional rehabilitation and may have important health economic implications as patients avoid hospitalization and are restored to full activities in society. The current team approach, which incorporates psychiatrists, psychologists, nutritionists, pediatricians, internists, and gastroenterologists in the treatment of patients with anorexia nervosa, will continue to be essential.

Bulimic symptoms in the Virginia Twin Study of Adolescent Behavioral Development: correlates, comorbidity, and genetics

BACKGROUND

This paper addresses bulimia symptoms in a large community sample of twins aged 8 to 17 years. We aim to identify environmental correlates of bulimia symptoms and relationships with other psychiatric disorder symptoms. The twin design allows examination of the structure of genetic and environmental effects.

METHODS

DSM-IIIR bulimia symptoms and consequential impairment were measured by interview in the first wave of the Virginia Twin Study of Adolescent Behavioral Development. Comorbidity with other psychiatric symptoms and environmental correlates were examined and the relative contributions of genes and environment were assessed using structural equation modeling.

RESULTS

An item-response theory model indicated that the range of bulimic symptoms represented a single underlying trait. Bulimia symptoms were more common in postmenarche girls and positively associated with body-mass index. Subdiagnostic symptomatology was associated with impairment in psychosocial functioning. Bulimia symptoms were strongly associated with other psychiatric disorders symptoms including anxiety and depression. Genetic model fitting identified strong additive genetic effects on the symptom score. Accounting for a potential violation of the equal environment assumption for identical and fraternal twins slightly reduced estimated genetic variance.

CONCLUSIONS

The pattern of comorbidity suggests overlap between bulimia symptoms and those of internalizing disorders. Substantial genetic variance (44%) was evident in the most conservative model.

Predicting children's reported eating disturbances at 8 years of age

OBJECTIVES

To examine differential parental influences on eating attitudes and behaviors of 8-year-old children with a specific focus on gender effects and to assess the specificity of this relationship.

METHOD

One hundred eight infants were monitored from birth and interviewed at age 8 for eating disturbances and negative affect with an adaptation of the McKnight Risk Factor Survey. Parental measures included the Three Factor Eating Questionnaire subscales Disinhibition and Restraint as well as body mass index, assessed at study entry.

RESULTS

No gender differences were found for frequencies of children's self-reported eating disturbances. Higher maternal restraint scores predicted worries about being too fat in girls but not in boys. Higher maternal disinhibition scores also differentially predicted weight control behaviors in their daughters. Negative affect in the child was (weakly) predicted by higher maternal body mass index. No association between paternal predictors of disturbed eating and the child's eating disturbances and negative emotionality was found.

CONCLUSIONS

The impact of maternal eating disorders and disturbances is much stronger than that of fathers and is specifically directed at their daughters. The clinical importance of these disturbances in terms of precursors of adolescent eating disorders has to be determined by monitoring the sample through puberty.

Research on eating disorders: current status and future prospects

This report summarizes the main themes addressed at a workshop on research on eating disorders (EDs), which was hosted by the National Institute of Mental Health in December 1998. Both basic behavioral neuroscientists and clinical investigators met in an effort to integrate areas of research and foster collaborations. Considerable advances have been made in understanding the neuroendocrinological mechanisms that regulate appetite and food intake. These achievements are in sharp contrast with the limited progress in elucidating the pathogenesis of EDs and developing effective treatment and preventive interventions. Anorexia nervosa remains a highly morbid condition with the highest mortality of any other psychiatric disorder. Besides acute refeeding techniques, no specific interventions have been proven effective in changing the long-term course of anorexia nervosa. Efficacious treatments exist for bulimia nervosa, but their underutilization calls for research on translating experimental findings into clinical practice. Closer interface between neuroscientists and clinical researchers is required for advancing our understanding of ED pathogenesis and developing effective treatments. Recent studies are suggestive of a substantial genetic contribution to EDs that deserves further investigation. Finally, there is an urgent need to examine risk and protective factors for EDs, on which safe and effective prevention can be built.