Genetic and environmental influences on thin-ideal internalization across puberty and preadolescent, adolescent, and young adult development

Exploring Sociocultural Influences Affecting Body Image in Survivors of Childhood Sexual Assault

This phenomenological study explored the lived experiences of survivors of childhood sexual assault, their meaning making process of the assault, and how messages from their sociocultural environment affected their relationship with, and perception of, their bodies. Utilizing a social constructivist framework, the research team interviewed eleven (n = 11) participants from a variety of backgrounds who were gender assigned female at birth and had survived childhood sexual assault (CSA). Four major themes emerged from the narratives collected. These include sociocultural impacts which included four subthemes: family relationships, peer relationships, societal and environmental influences, and cultural and ethnic influences; meaning making of the critical event, i.e., childhood sexual assault; self-perception of their bodies; internal processes that have shaped their perceptions and meaning making, i.e., thoughts, feelings, and behaviors. Findings indicate major influence of sociocultural factors in shaping participant's internal processes as survivors of CSA, meaning making, and subsequently self-perceptions of, and relationship with, their bodies. We discuss CSA and body image keeping the intersectionality of the individual, their experiences, and the impact of sociocultural contexts on that intersectionality.

State of Mind Assessment in Relation to Adult Attachment and Text Analysis of Adult Attachment Interviews in a Sample of Patients with Anorexia Nervosa

BACKGROUND

Attachment theory represents one of the most important references for the study of the development of an individual throughout their life cycle and provides the clinician with a profound key for the purposes of understanding the suffering that underlies severe psychopathologies such as eating disorders. As such, we conducted a cross-sectional study with a mixed-methods analysis on a sample of 32 young women with anorexia nervosa (AN); this study was embedded in the utilized theoretical framework with the following aims: 1. to evaluate the state of mind (SoM) in relation to adult attachment, assuming a prevalence of the dismissing (DS) SoM and 2. to analyze the linguistic attachment profile emerging from the transcripts of the AAIs.

METHODS

Interviews were transcribed verbatim, coded, and analyzed using the linguistic inquiry and word count (LIWC) method.

RESULTS

The results were observed to be consistent with the referenced literature. The prevalence of a DS SoM (68.75%) is observed in the study sample, whereas the results of the lexical analysis of the stories deviate from expectations. Notably, the lexical results indicate the coexistence of the dismissing and entangled aspects at the representational level.

CONCLUSIONS

The study results suggest a high level of specificity in the emotional functioning of patients with AN, with a focusing on a pervasive control of emotions that is well illustrated by the avoidant/ambivalent (A/C) strategy described in Crittenden's dynamic-maturational model. These findings and considerations have important implications for clinical work and treatment, which we believe must be structured on the basis of starting from a reappraisal of emotional content.

Body-Related Attitudes, Personality, and Identity in Female Adolescents with Anorexia Nervosa or Other Mental Disorders

The psychological integration of body-related attitudes (BodyRA) is a critical developmental task in adolescence. Adolescents must adapt to their changing body image and body satisfaction. For young people, BodyRA (body dissatisfaction, bulimia, and drive for thinness) are connected to insecurities, which can disturb identity integration and personality development. Our goal was to evaluate the importance of BodyRA also for other mental disorders other than anorexia nervosa (AN), and the association between BodyRA with temperament and personality traits and identity diffusion. Data for the period of 2012 to 2019 were retrospectively analyzed from a convenience sample of patients in a child and adolescent psychiatric hospital (n = 114). The patients were 13 to 17 years of age and had a BMI of 11.9−36.1 kg/m2. As expected, BodyRA were found to be more pronounced in AN, as well as in borderline personality disorder (BPD), depression (DD), and attention deficit hyperactivity disorder (ADHD). BodyRA correlated significantly with internalizing problems in patients with DD (r = 0.428−0.565, p < 0.01) and BPD (r = 0.680, p < 0.01) as well as with BMI (r = 0.404, p < 0.01) in patients with DD. Moreover, we detected significant correlations with impaired identity development in patients with DD (r = 0.482−0.565, p < 0.01) and BPD (r = 0.681−0.703, p < 0.01). BodyRA also correlated significantly with the personality traits of harm avoidance (r = 0.377−0.541, p < 0.01) and self-directedness (r = −0.537−−0.635, p < 0.01) in DD. These personality traits and bulimia were used as predictors for identity diffusion in the investigated disorders of this study. We conclude that BodyRA, harm avoidance and self-directedness are associated with identity development in adolescent females with mental disorders.

The role of personality traits, sociocultural factors, and body dissatisfaction in anorexia readiness syndrome in women

BACKGROUND

The mass media promote certain standards of physical attractiveness. The media coverage, in interaction with body dissatisfaction and personality traits, may intensify specified behaviors in women, that should help them to obtain an ideal body image, e.g., excessive concentration on body image, weight control, increase in physical activity. The intensification of these behaviors can develop anorexia readiness syndrome (ARS) in women. The paper presents a study on the role of the Five-Factor Model personality traits (neuroticism, extraversion, agreeableness, conscientiousness, and intellect/openness), sociocultural factors (internalization, sociocultural pressure, information seeking), and body dissatisfaction in anorexia readiness syndrome.

METHODS

The study involved 1533 Polish women aged 18-36 (M = 22.51, SD = 2.41). The participants completed the online version of the set of questionnaires. The link to the study was shared in social media groups. Personality dimensions were measured with the BFI, sociocultural factors were evaluated by means of the SATAQ-3, the degree of body dissatisfaction was assessed with the BIQ, while ARS was measured using five self-reported items referring to specific behaviors from TIAE.

RESULTS

Hierarchical multiple regression analysis revealed internalization, sociocultural pressure, and body dissatisfaction as significant predictors of ARS. While neuroticism was correlated with ARS, it lost its predictive value after entering body dissatisfaction in the regression model.

CONCLUSIONS

The factors associated with ARS were (1) neuroticism among personality traits, (2) internalization and pressure from sociocultural norms among sociocultural attitudes, and (3) body dissatisfaction. The key finding is the absence of statistical significance for neuroticism in predicting ARS after including body dissatisfaction. In future research, the group of men and patients with anorexia nervosa can be included, and the age range can be extended to include younger people. The catalog of potential ARS predictors may be expanded, which can help to explain the role of neuroticism in ARS.

A test of the tripartite influence model of disordered eating among men

Studies of the Tripartite Influence Model conducted with female samples suggest that thinness-oriented pressures, internalization, and appearance comparisons may be risk factors for disordered eating. However, limited work has investigated this model among men utilizing measures specifically designed to assess both muscularity- and thinness-oriented processes, which characterize male body image concerns. To address this gap, the current study examined the Tripartite Influence Model of disordered eating among men using a battery of such measures. A convenience sample of 265 male undergraduates completed validated, self-report measures of disordered eating, muscularity- and thinness-oriented appearance pressures, internalization, and appearance comparisons. Path analyses supported a slightly modified version of the Tripartite Influence Model, indicating direct and indirect paths from sociocultural pressures to disordered eating via internalization and appearance comparisons. These results provide support for a version of the Tripartite Influence Model among men. Specifically, muscularity- and thinness-oriented pressures appear to be related to disordered eating among college men via indirect pathways involving thin internalization, muscular internalization, and appearance comparisons. Future work is needed, however, to examine whether the model would generalize to muscularity-oriented disordered eating.

Psychometric properties of measures of sociocultural influence and internalization of appearance ideals across eight countries

The aim of the current study was to examine the psychometric properties of two well-established measures of sociocultural influence and internalization of the thin/low body fat ideal and muscular ideal. Data from 6272 emerging adults (68.9 % female), aged 18-30 years from Australia, Belgium, Canada, China, Italy, Japan, Spain, and the U.S. were included in this study. Participants completed measures of pressure from mother, fathers, peers, and media, to both increase muscles and lose weight, as well as internalization of the thin/low body fat ideal and muscular ideal. Overall, support for partial invariance was found across the scales. In addition, group level differences were found between countries as well as along demographic factors including gender, age, body mass index, and socioeconomic status. These findings make an important contribution by identifying these scales as useful tools that will support future cross-country and cross-cultural examinations of explanatory models of the development of body image and eating concerns grounded within sociocultural theories.

Momentary associations between positive affect dimensions and dysregulated eating during puberty in a diverse sample of youth with overweight/obesity

OBJECTIVE

The link between dysregulated positive affect and binge-eating behavior in youth with obesity is poorly understood. In addition, it is unclear how putative associations differ across developmental periods of rapid biological and emotional change, such as puberty, and in racial and ethnic minority youth, who are more likely to be overweight but are underrepresented in the literature.

METHOD

This study used a 2-week ecological momentary assessment protocol to examine independent and interactive effects of positive affect intensity/instability, and pubertal stage on two components of binge-eating behavior, loss of control eating (LOCE), and overeating.

RESULTS

Participants were 38 youth with overweight/obesity (ages 8-14 years; 78% African American/Hispanic). Positive affect instability was calculated using probability of acute change (PAC), representing the likelihood of extreme affective changes, and mean squared successive difference (MSSD), representing the average change in affect over successive recordings. There were no main effects of positive affect intensity on LOCE or overeating, but positive affect instability was negatively associated with overeating severity using both MSSD (p = .005) and PAC metrics (p = .001). However, moderation analyses including interactions with pubertal status revealed more extreme changes in positive affect (i.e., higher PAC) were related to greater overeating (p = .001) and LOCE severity (p = .043) in mid-late pubertal youth but not in pre-early pubertal youth.

DISCUSSION

Pubertal status may influence the association between disruptions in positive affect and dysregulated eating in youth, and positive affect instability may be important to consider in order to understand the emotional correlates of binge eating in youth with overweight/obesity.

Iowa Gambling Task and Distortion in Perception of Body Image Among Adolescent Women With Eating Disorders

The Iowa gambling task (IGT) is an instrument for the neuropsychological evaluation of cognitive and emotional decision making (DM) processes that was created to test the somatic marker hypothesis (SMH) described by Damasio in 1994. It was initially applied to patients with frontal lobe lesions due to its association with executive functions but was subsequently used on patients with a variety of disorders. Although the DM process is inherently perceptual, few studies have applied the IGT to examine DM processes in patients with eating disorders (EDs), and even fewer have associated the IGT to the perceptual distortion of body image (PDBI) in this population. People diagnosed with ED exhibit heightened control over their somatic responses-for example, they can delay digestion for hours-and DM may be affected in this condition. This study compares the performance of two samples of adolescent women-hospitalized patients with ED, and healthy controls with similar demographic characteristics-on the IGT using body image as a possible factor in the SMH. Seventy-four women with a mean age of 14.97 years (SD = 2.347) participated. To analyze their body self-image, we used the figure-rating scale and compared the results with their body mass index (BMI). Correlations between indices of the IGT and distortion in body image were then explored. The results revealed significant differences between the groups in terms of evolving performance on the partial IGT. Patients with ED performed worse than their healthy counterparts in the last 40 trials and exhibited greater distortions in their body image, especially in terms of overestimation. Indices of these distortions were negatively correlated with the total IGT. These results are compatible with the SMH because they suggest that patients with ED evinced blindness with regard to the future, as described by their authors. In addition, a negative correlation was found between the IGT and PDBI, showing that a more distorted body image was associated with lower IGT, that is, more disadvantageous or riskier decisions were made by the subjects with more distortion.

Prolonged constipation and diarrhea in childhood and disordered eating in adolescence

OBJECTIVES

Gastrointestinal problems are common in all eating disorders; however, the extent to which these problems predate the onset of eating disorders is not clear. We explored longitudinal associations between childhood gastrointestinal problems and adolescent disordered eating, and assessed whether observed associations are potentially causal or due to familial confounding factors.

METHODS

Data from a population-based Swedish twin sample were used to investigate associations between parent- and self-reported protracted constipation and diarrhea in childhood and adolescence, and later disordered eating, measured by the Eating Disorders Inventory-2 (EDI). Linear regression models were used to investigate the associations. Possible familial confounding was explored by using a within-twin pair analysis.

RESULTS

We found that those who reported a history of constipation at age 15 scored 5.55 and 5.04 points higher, respectively, on the EDI total score at age 15 and 18, compared with those without constipation. Those reporting a history of diarrhea at age 15 scored 5.15 points higher, and the group reporting both problems scored 9.52 points higher on the EDI total score at age 15 than those reporting no problems. We observed that the association between constipation and disordered eating was attenuated in the within-twin pair analysis, but remained positive.

CONCLUSIONS

Gastrointestinal problems in childhood and adolescence are significantly associated with disordered eating. Associations were partly due to familial confounding, but might also be consistent with a causal interpretation. Clinicians should be aware of the increased risk of disordered eating when following children and adolescents who present with gastrointestinal problems.

A Systematic Review of Sexual Orientation Disparities in Disordered Eating and Weight-Related Behaviors among Adolescents and Young Adults: Toward a Developmental Model

Adolescence is a sensitive period for the development of disordered eating and weight-related behaviors, and sexual minorities may be particularly at risk due to heightened minority stress and challenges related to sexual identity development. This review synthesized findings from 32 articles that examined sexual orientation disparities (each with a heterosexual referent group) in four disordered eating behaviors (binging, purging, restrictive dieting, diet pill use) and four weight-related behaviors (eating behaviors, physical activity, body image, and Body Mass Index [BMI]). Potential variations by outcome, sex, race/ethnicity, and developmental stage were systematically reviewed. Evidence supporting sexual orientation disparities in disordered eating and weight-related behaviors was more consistent among males than females. Among females, sexual orientation disparities in disordered eating behaviors appeared to be more pronounced during adolescence than in young adulthood. Sexual minority females generally reported more positive body image than heterosexual females but experienced disparities in BMI. Sexual orientation differences in eating behaviors and physical activity were especially understudied. Incorporating objectification and minority stress theory, a developmental model was devised where body image was conceptualized as a key mechanism leading to disordered eating behaviors. To advance understanding of sexual orientation disparities and tailor intervention efforts, research in this field should utilize longitudinal study designs to examine developmental variations and incorporate multi-dimensional measurements of sexual orientation and body image.

Adult Separation Anxiety Disorder Symptomology as a Risk Factor for Thin-Ideal Internalization: The Role of Self-Concept Clarity

The study of when and how individuals compare themselves against standards has been an enduring focus for clinical and social psychology researchers in efforts to facilitate well-being and health. Our study focused on internalization of the societal thin-ideal standard for feminine attractiveness, a construct that has proven to be very important in women's psychological health. Although multiple adverse consequences of thin-ideal internalization have been documented, the understanding of variability in the extent of thin-ideal internalization across women (e.g., why do some women strongly internalize thin-ideal standards when others do not?) is much less well developed. This research was conducted to explore the role of adult separation anxiety disorder (ASAD) symptomology and conceptions of the self in young women's propensity to internalize the thin-ideal attractiveness standard. Results show that elevated ASAD symptoms are associated with greater thin-ideal internalization. A structural equations model demonstrates the reason for this association; young women with higher ASAD symptomology exhibit lower self-concept clarity, which drives greater thin-ideal internalization. This research makes novel practical and conceptual contributions by (a) delineating a new risk factor for the development of thin-ideal internalization, (b) highlighting a previously undocumented vulnerability of women who experience ASAD symptoms, and (c) documenting the relationship between ASAD and lower self-concept clarity. Implications for mental health practitioners are discussed.

Media ideals and early adolescents' body image: Selective avoidance or selective exposure?

The present study combines selective exposure theory with body image coping literature to study effects of media internalization in early adolescence. The main objective was to explore how early adolescents selectively internalize media body ideals to manage their body image. To examine the role of media internalization in early adolescents' body image management, we used two-wave panel data (N_Wave1 = 1986) gathered among 9- to 14-year-olds. Structural equation analyses indicated that media internalization (Wave 1) positively related to body surveillance (Wave 2). Body surveillance (Wave 2), in turn, was associated with more body image self-discrepancy (Wave 2). In addition, body image self-discrepancy (Wave 1) related to higher body surveillance (Wave 1). Body surveillance, in turn, related to more media internalization cross-sectionally, but less media internalization six months later. Taken together, these results suggest a role for media internalization in early adolescents' body image management. Theoretical and practical implications are discussed.

Eating Disorder Symptomatology and Identity Formation in Adolescence: A Cross-Lagged Longitudinal Approach

Introduction: Eating disorder symptomatology, comprising both psychological and behavioral aspects of subclinical eating concerns, constitutes a clear precursor of developing eating disorders. It is crucial to investigate its antecedents and correlates to subsequently inform eating disorder prevention programs. The present study focused on identity formation, a core developmental task in adolescence, that has increasingly been linked to eating disorder development. Our main aim was to examine the temporal sequence between eating disorder symptomatology and identity formation. Methods: Data on eating disorder symptomatology and identity formation were collected in 530 high school students (at Time 1: mean age = 15 years; SD = 1.84; range: 12-18 years; 50.6% females) using self-report questionnaires at three annual measurement points. Cross-lagged structural equation modeling was performed to examine the directionality of effects. Results: Results indicated bidirectional effects between eating disorder symptomatology and identity formation. Identity confusion seemed to increase vulnerability to body dissatisfaction and bulimia symptoms, whereas identity synthesis seemed to protect against their development. Additionally, identity synthesis seemed to protect against the development of drive for thinness as well. At the same time, body dissatisfaction and bulimia symptoms positively predicted identity confusion and negatively predicted identity synthesis over time. Conclusion: The present study adds to the growing body of literature on identity and eating disorders by focusing on their temporal interplay in a community sample of adolescents. As bidirectional effects emerged, a greater emphasis on identity formation in eating disorder prevention programs is advocated.

Obesity and eating disorders in integrative prevention programmes for adolescents: protocol for a systematic review and meta-analysis

INTRODUCTION

Obesity and eating disorders are public health problems that have lifelong financial and personal costs and common risk factors, for example, body dissatisfaction, weight teasing and disordered eating. Obesity prevention interventions might lead to the development of an eating disorder since focusing on weight may contribute to excessive concern with diet and weight. Therefore, the proposed research will assess whether integrating obesity and eating disorder prevention procedures ('integrated approach') do better than single approach interventions in preventing obesity among adolescents, and if integrated approaches influence weight-related outcomes.

METHODS AND ANALYSIS

Integrated obesity and eating disorder prevention interventions will be identified. Randomised controlled trials and quasi-experimental trials reporting data on adolescents ranging from 10 to 19 years of age from both sexes will be included. Outcomes of interest include body composition, unhealthy weight control behaviours and body satisfaction measurements. MEDLINE/PubMed, PsycINFO, Web of Science and SciELO will be searched. Data will be extracted independently by two reviewers using a standardised data extraction form. Trial quality will be assessed using the Cochrane Collaboration criteria. The effects of integrated versus single approach intervention studies will be compared using systematic review procedures. If an adequate number of studies report data on integrated interventions among similar populations (k>5), a meta-analysis with random effects will be conducted. Sensitivity analyses and meta-regression will be performed only if between-study heterogeneity is high (I² ≥75%).

ETHICS AND DISSEMINATION

Ethics approval will not be required as this is a systematic review of published studies. The findings will be disseminated through conference presentations and peer-reviewed journals.

The Science Behind the Academy for Eating Disorders' Nine Truths About Eating Disorders

OBJECTIVE

In 2015, the Academy for Eating Disorders collaborated with international patient, advocacy, and parent organizations to craft the 'Nine Truths About Eating Disorders'. This document has been translated into over 30 languages and has been distributed globally to replace outdated and erroneous stereotypes about eating disorders with factual information. In this paper, we review the state of the science supporting the 'Nine Truths'.

METHODS

The literature supporting each of the 'Nine Truths' was reviewed, summarized and richly annotated.

RESULTS

Most of the 'Nine Truths' arise from well-established foundations in the scientific literature. Additional evidence is required to further substantiate some of the assertions in the document. Future investigations are needed in all areas to deepen our understanding of eating disorders, their causes and their treatments.

CONCLUSIONS

The 'Nine Truths About Eating Disorders' is a guiding document to accelerate global dissemination of accurate and evidence-informed information about eating disorders. Copyright © 2017 John Wiley & Sons, Ltd and Eating Disorders Association.

Expanding the developmental boundaries of etiologic effects: The role of adrenarche in genetic influences on disordered eating in males

Genetic influences on disordered eating (DE) increase across age and puberty in girls, an effect that is at least partially due to ovarian hormone activation. However, development shifts in genetic effects have not been detected in boys; genetic influences have been found to be relatively constant from prepuberty to adulthood, suggesting that gonadal hormones may be less important. One caveat is that studies have examined males ages 10 or older. Genetic effects on DE may emerge earlier in boys, such as during adrenarche, when androgens begin to increase but the physical changes of puberty are not yet observable. The current study investigated this hypothesis in 1,212 male twins (ages 6-28) from the Michigan State University Twin Registry. Results supported a potential role of adrenarche, as genetic influences on DE increased during middle childhood, prior to the external physical changes of puberty. Specifically, genetic influences on DE were negligible (0%) in twins during pre- to early adrenarche, but increased incrementally across advancing adrenarche (17% to 44%) and into early puberty (57%). Genetic effects then remained stable into midpuberty and postpuberty (58%), suggesting that nearly all of the genetic effects on DE become prominent during adrenarche in males. Findings suggest that genetic effects on DE emerge sooner in boys than the midpubertal activation that is consistently found in girls. These data highlight a potentially important role for adrenarche in the genetic diathesis for DE in males and a need to examine younger ages in studies of developmental effects. (PsycINFO Database Record

Weight-related peer-teasing moderates genetic and environmental risk and disordered eating: twin study

BackgroundWeight-related peer-teasing is considered a potent prospective risk factor for development of disordered eating and clinical eating disorders. Currently, the interplay between genetic and environmental influences has yet to be elucidated.AimsTo determine whether peer-teasing moderates latent genetic and/or environmental risk for disordered eating among female adolescent twins.MethodFull quantitative gene-environment interplay modelling of longitudinal trajectory of disordered eating in 685 female twins from the Australian Twin Registry.ResultsA model permitting moderation of disordered eating by peer-teasing involving genetic and non-shared environment effects fit these data best. As levels of peer-teasing increased, both genetic and environmental influences on disordered eating strengthened; however, genetic sources increased proportionally more than environmental sources.ConclusionsWeight-related peer-teasing represents a particularly powerful trigger for disordered eating. Nevertheless, it is amenable to intervention/prevention activities spanning individual to universal levels of endeavour.

Cost-effectiveness of achieving clinical improvement with a dissonance-based eating disorder prevention program

Using data from an effectiveness trial delivered by college clinicians, we examined the cost-effectiveness of the dissonance-based Body Project program for reducing eating disorder symptoms in women with body dissatisfaction. The outcome of interest was individual-level change; 14.9% of Body Project participants attained clinically meaningful improvement vs. 6.7% of controls. Delivering the intervention costs approximately $70 (2012 U.S. dollars) per person. Incremental cost-effectiveness was $838 for each additional at-risk person reducing eating disorder symptomology to a clinically meaningful degree. These analyses demonstrate the economic value of the Body Project for college-age women with symptoms below the eating disorder diagnosis threshold.

Differential Effects of Estrogen and Progesterone on Genetic and Environmental Risk for Emotional Eating in Women

Recent data show shifts in genetic and environmental influences on emotional eating across the menstrual cycle, with significant shared environmental influences during pre-ovulation, and primarily genetic effects during post-ovulation. Factors driving differential effects are unknown, although increased estradiol during pre-ovulation and increased progesterone during post-ovulation are thought to play a role. We indirectly investigated this possibility by examining whether overall levels of estradiol and progesterone differentially impact genetic and environmental risk for emotional eating in adult female twins (N = 571) drawn from the MSU Twin Registry. Emotional eating, estradiol levels, and progesterone levels were assessed daily and then averaged to create aggregate measures for analysis. As predicted, shared environmental influences were significantly greater in twins with high estradiol levels, whereas additive genetic effects increased substantially across low versus high progesterone groups. Results highlight significant and differential effects of ovarian hormones on etiologic risk for emotional eating in adulthood.

Family factors and health behaviour of thin adolescent boys and girls

AIM

The aim of this study was to examine prevalence of extreme thinness and thinness in adolescent boys and girls and to study associations between family factors, health behaviour and thinness in boys and girls.

BACKGROUND

Extreme thinness carries high health risks. The family and health behavioural factors related to adolescent thinness have not been studied previously using a nationally representative data.

DESIGN

This is a cross-sectional quantitative study.

METHODS

The nationally representative data were obtained from the Finnish School Health Promotion study conducted in 2013. The sample of this study included 12-17 year old adolescents (n = 71,973) who were categorised as extremely thin, thin and normal weight using international age and gender body mass index (BMI) cut-off points for children and adolescents. Associations with family factors and health behaviour were examined separately for boys and girls using cross-tabulations, Chi-square test and multinomial logistic regression.

RESULTS

Thinness and extreme thinness were more common in girls than in boys. Health behaviour, such as smoking and exercise, were associated with thinness and extreme thinness in both genders. Regarding family factors; low maternal education, family meal and parental knowledge of adolescents' friends and whereabouts were associated with thinness and, or extreme thinness in both boys and girls. However, there were gender differences in the associations.

CONCLUSIONS

It is important for healthcare professionals working with adolescents to be aware of prevalence in thinness and aware of health behaviour and family factors that are associated with thinness and extreme thinness in adolescence.

Socialization and selection effects in the association between weight conscious peer groups and thin-ideal internalization: A co-twin control study

Affiliation with weight conscious peer groups is theorized to increase thin-ideal internalization through socialization processes. However, selection effects could contribute if genetic and/or environmental predispositions lead to affiliation with weight conscious peers. Co-twin control methodology was used to examine socialization and selection effects in 614 female twins (ages 8-15) from the Michigan State University Twin Registry (MSUTR). Thin-ideal internalization and peer group characteristics were assessed via self-report questionnaires. Results suggested the presence of both socialization and selection effects. In terms of socialization, twins who reported increased exposure to weight conscious peers relative to their co-twins had elevated thin-ideal internalization scores, regardless of zygosity. However, associations between weight conscious peers and thin-ideal internationalization within twin pairs were attenuated, suggesting that genetic and shared environmental selection effects also contribute. Findings significantly extend previous work by confirming the presence of socialization processes and highlighting selection processes to be examined in future longitudinal research.

The dimensional nature of eating pathology: Evidence from a direct comparison of categorical, dimensional, and hybrid models

Eating disorders are conceptualized as categorical rather than dimensional in the current major diagnostic system (Diagnostic and Statistical Manual of Mental Disorders; 5th ed.; American Psychiatric Association, 2013) and in many previous studies. However, previous research has not critically evaluated this assumption or tested hybrid models (e.g., modeling latent variables with both dimensional and categorical features). Accordingly, the current study directly compared categorical, dimensional, and hybrid models for eating pathology in a large, population-based sample. Participants included 3,032 female and male twins (ages 9-30 years) from the Michigan State University Twin Registry. The Minnesota Eating Behaviors Survey was used to assess disordered eating symptoms including body dissatisfaction, weight preoccupation, binge eating, and compensatory behaviors. Results showed that dimensional models best fit the data in the overall sample as well as across subgroups divided by sex and pubertal status (e.g., prepubertal vs. postpubertal). It is interesting to note that the results favored more categorical models when using a case-control subset of our sample with participants who either endorsed substantial eating pathology or no/little eating pathology. Overall, findings provide support for a dimensional conceptualization of eating pathology and underscore the importance of using community samples to capture the full range of severity of eating pathology when investigating questions about taxonomy. (PsycINFO Database Record

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

BACKGROUND

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

METHODS

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

FINDINGS

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

CONCLUSIONS

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

Stigma, Obesity and Adolescent Risk Behaviors: Current Research and Future Directions

Adolescents are particularly vulnerable to risk behaviors as, in this life stage, they are experiencing intense physical, psychological and social changes. Adolescents who are overweight/obese, but particularly those who perceive themselves as such, are more likely to engage in risk behaviors than those who are or perceive themselves of normal-weight. Weight stigma and discrimination may contribute to this association as they reinforce poor body image and create intense stress. Stress is associated with poor emotion regulation, more impulsive, contextually-determined, and less rational decision-making, leading to greater engagement in risk behaviors. However, pathways from weight stigma/discrimination to risk behavior may be moderated by adolescents' social networks. This review provides a conceptual model and empirical evidence to illustrate the proposed pathways from weight stigma and discrimination to risk behaviors. Public health implications and future research directions are also discussed.