Sarah E. Racine

The interactive effects of estrogen and progesterone on changes in emotional eating across the menstrual cycle

Studies suggest that within-person changes in estrogen and progesterone predict changes in binge eating across the menstrual cycle. However, samples have been extremely small (maximum N = 9), and analyses have not examined the interactive effects of hormones that are critical for changes in food intake in animals. The aims of the current study were to examine ovarian hormone interactions in the prediction of within-subject changes in emotional eating in the largest sample of women to date (N = 196). Participants provided daily ratings of emotional eating and saliva samples for hormone measurement for 45 consecutive days. Results confirmed that changes in ovarian hormones predict changes in emotional eating across the menstrual cycle, with a significant estradiol × progesterone interaction. Emotional eating scores were highest during the midluteal phase, when progesterone peaks and estradiol demonstrates a secondary peak. Findings extend previous work by highlighting significant interactions between estrogen and progesterone that explain midluteal increases in emotional eating. Future work should explore mechanisms (e.g., gene-hormone interactions) that contribute to both within- and between-subjects differences in emotional eating.

Emotion dysregulation and symptoms of anorexia nervosa: The unique roles of lack of emotional awareness and impulse control difficulties when upset

OBJECTIVE Extant research suggests that individuals with anorexia nervosa (AN) have deficits in emotion regulation across a variety of domains. The current study investigated associations between specific difficulties with emotion regulation and the core symptoms of AN. METHOD Participants were 192 patients with AN presenting to an intensive eating disorder treatment facility. Emotion regulation was assessed using the multidimensional Difficulties in Emotion Regulation Scale, and associations with body mass index (BMI) at admission, eating disorder cognitions, objective binge eating, subjective binge eating, and purging were examined. RESULTS Eating disorder cognitions were significantly associated with multiple forms of emotion dysregulation; however, only lack of emotional awareness was independently related to these symptoms. In contrast, impulse control difficulties when upset was the only emotion regulation impairment associated with the presence of recurrent objective binge eating and recurrent purging in AN. No significant relationships between emotion regulation and BMI or subjective binge eating were detected. DISCUSSION Results point to differential associations between specific emotion regulation deficits and core symptoms of AN. These findings suggest that parsing the construct of emotion regulation as well as the AN phenotype can help to identify the unique ways in which eating disorder symptoms may function to regulate emotions.

The possible influence of impulsivity and dietary restraint on associations between serotonin genes and binge eating

Although serotonin (5-HT) genes are thought to be involved in the etiology of bulimia nervosa and binge eating, findings from molecular genetic studies are inconclusive. This may be due to limitations of past research, such as a failure to consider the influence of quantitative traits and gene-environment interactions. The current study investigated these issues by examining whether quantitative traits (i.e., impulsivity) and environmental exposure factors (i.e., dietary restraint) moderate 5-HT gene/binge eating associations in a sample of young women (N = 344). Binge eating was assessed using the Minnesota Eating Behavior Survey and the Dutch Eating Behavior Questionnaire (DEBQ). Impulsivity was assessed with the Barratt Impulsiveness Scale-Version 11. Dietary restraint was measured with a factor score derived from common restraint scales. Saliva samples were genotyped for the 5-HT2a receptor T102C polymorphism and 5-HT transporter promoter polymorphism. As expected, impulsivity and dietary restraint were associated with binge eating. Although the T allele of the 5-HT2a receptor gene and the s allele of the 5-HTT gene were associated with higher levels of impulsivity, there were no main effects of 5-HT genotypes on any binge eating measure, and interactions between genotypes, impulsivity, and dietary restraint were non-significant. In conclusion, we found no evidence to suggest that dietary restraint or impulsivity moderate associations between binge eating and these 5-HT genes. Future research should continue to explore interaction effects by examining larger samples, assessing dietary intake directly, and investigating other genes, traits, and environmental factors that may be related to binge eating and bulimia nervosa.

Exploring the relationship between negative urgency and dysregulated eating: etiologic associations and the role of negative affect.

Negative urgency (i.e., the tendency to engage in rash action in response to negative affect) has emerged as a critical personality trait contributing to individual differences in binge eating. However, studies investigating the extent to which genetic and/or environmental influences underlie the effects of negative urgency on binge eating are lacking. Moreover, it remains unclear whether negative urgency-binge eating associations are simply a result of the well-established role of negative affect in the development/maintenance of binge eating. The current study addresses these gaps by examining phenotypic and etiologic associations between negative urgency, negative affect, and dysregulated eating (i.e., binge eating, emotional eating) in a sample of 222 same-sex female twin pairs from the Michigan State University Twin Registry. Negative urgency was significantly associated with both dysregulated eating symptoms, even after controlling for the effects of negative affect. Genetic factors accounted for the majority (62-77%) of this phenotypic association, although a significant proportion of this genetic covariation was due to genetic influences in common with negative affect. Nonshared environmental factors accounted for a relatively smaller (23-38%) proportion of the association, but these nonshared environmental effects were independent of negative affect. Findings suggest that the presence of emotion-based rash action, combined with high levels of negative affect, may significantly increase genetic risk for dysregulated eating.

Sex differences in binge eating patterns in male and female adult rats

OBJECTIVE Several efforts are underway to model binge eating in animals in order to advance neurobiological models of risk. However, knowledge of sex differences in these models is currently lacking. The goal of the present study was to examine sex differences in binge eating phenotypes using a well-established rodent model (i.e., the binge eating resistant/binge eating prone model). METHOD Thirty male and 30 female adult Sprague-Dawley rats were exposed to feeding tests consisting of intermittent access to palatable food (PF). Rats were then categorized as binge eating prone (BEP) based on the amount and consistency of PF consumption across tests. RESULTS Across multiple methods for BEP classification, rates of BEP phenotypes were two to six times higher in female than male rats. DISCUSSION Findings provide support for sex differences in rodent models of binge eating and highlight the promise of the BER/BEP model for understanding neurobiological mechanisms underlying sex differences in risk.

Examining the relationship between dietary restraint and binge eating: differential effects of major and minor stressors.

This study sought to examine the complex interactive impact of major stress and minor stressors on the relation between dietary restraint and binge eating. Participants were 497 undergraduate females who completed an online questionnaire that included measures of binge eating (modified version of the bulimia scale of the Eating Disorder Inventory-2; EDI-2), major life stressors (the Social Readjustment Rating Scale; SRRS), minor stressors (Daily Stress Inventory; DSI), and dietary restraint (Restraint Scale; RS). A hierarchal linear regression revealed a significant three-way interaction among dietary restraint, life event stress, and daily stress that accounted for a significant proportion of the variance in binge eating above and beyond all main effects and two-way interactions. Findings suggested that the interactive relationship among dietary restraint and daily stress is present only under conditions of high life event stress. Overall, the relationship between dietary restraint and binge eating appears to be quite complex and dependent upon differential levels of daily and life event stressors.

Differential associations between ovarian hormones and disordered eating symptoms across the menstrual cycle in women

OBJECTIVE We examined changes in drive for thinness, body dissatisfaction, and dietary restraint across the menstrual cycle and associations between these symptoms and ovarian hormones in two independent samples of women (N = 10 and 8 women, respectively) drawn from the community. METHOD Daily self-report measures of disordered eating and negative affect were completed for 35-65 days. Daily saliva samples were assayed for estradiol and progesterone in Study 2 only. RESULTS Levels of body dissatisfaction and drive for thinness were highest during the mid-luteal/pre-menstrual phases in both studies and were negatively associated with estradiol, and positively associated with progesterone. By contrast, dietary restraint showed less variation across the menstrual cycle and weaker associations with ovarian hormones. DISCUSSION Differential associations between ovarian hormones and specific disordered eating symptoms point to distinct etiological processes within the broader construct of disordered eating.

Dietary restraint moderates genetic risk for binge eating

Dietary restraint is a prospective risk factor for the development of binge eating and bulimia nervosa. Although many women engage in dietary restraint, relatively few develop binge eating. Dietary restraint may increase susceptibility for binge eating only in individuals who are at genetic risk. Specifically, dietary restraint may be a behavioral exposure factor that activates genetic predispositions for binge eating. We investigated this possibility in 1,678 young adolescent and adult same-sex female twins from the Minnesota Twin Family Study and the Michigan State University Twin Registry. Twin moderation models were used to examine whether levels of dietary restraint moderate genetic and environmental influences on binge eating. Results indicated that genetic and nonshared environmental factors for binge eating increased at higher levels of dietary restraint. These effects were present after controlling for age, body mass index, and genetic and environmental overlap among dietary restraint and binge eating. Results suggest that dietary restraint may be most important for individuals at genetic risk for binge eating and that the combination of these factors could enhance individual differences in risk for binge eating.

Dynamic longitudinal relations between emotion regulation difficulties and anorexia nervosa symptoms over the year following intensive treatment.

OBJECTIVE Emotion regulation difficulties have been implicated in theoretical models of anorexia nervosa (AN) development/maintenance, and several treatments for AN have been designed to target emotion dysregulation. However, no research has used longitudinal methodology to examine whether emotion regulation difficulties predict the maintenance of AN symptoms, or vice versa. The current study evaluated dynamic longitudinal relations between emotion dysregulation and AN symptom severity over the year following discharge from intensive treatment in order to enhance theoretical models and treatments for AN. METHOD Participants were 191 patients with AN recruited during intensive treatment. Assessments including the Eating Disorders Examination and the Difficulties in Emotion Regulation Scale were completed at discharge from treatment and at 3-, 6-, and 12-month follow-ups. Bivariate latent change score models were used to examine the direction of associations between emotion dysregulation and AN symptom severity across time. RESULTS Emotion dysregulation predicted change in AN symptom severity, but the reverse relationship did not occur. Individuals with high levels of emotion dysregulation experienced an increase and subsequent maintenance of AN psychopathology, whereas low emotion dysregulation predicted a decreasing AN symptom trajectory. Importantly, these dynamic temporal relationships could not be accounted for by body mass index or depressive symptoms and were present for patients with the restricting and binge-eating/purging subtypes of AN. CONCLUSIONS Emotion regulation difficulties appear to be involved in the maintenance of AN symptom severity over time. Findings provide support for an increasing emphasis on emotion regulation in the development of novel treatments for AN.

Emotion dysregulation and anorexia nervosa: An exploration of the role of childhood abuse

OBJECTIVE Theoretical models of emotion regulation difficulties in anorexia nervosa (AN) specify a role for factors that predispose to or precipitate emotion dysregulation. The current study considered whether childhood abuse (i.e., emotional, sexual, physical) might be related to emotion regulation difficulties and eating disorder symptom severity in patients with AN. Childhood abuse was hypothesized to relate to AN symptoms indirectly via emotion dysregulation. METHOD Participants were 188 patients with AN presenting to an intensive treatment facility. The Childhood Trauma Questionnaire, Difficulties in Emotion Regulation Scale, and Eating Disorder Examination were used to assess childhood abuse, emotion dysregulation, and AN symptom severity, respectively. RESULTS Of the three forms of childhood abuse, reports of emotional abuse were most strongly related to emotion regulation difficulties and AN symptom severity. Mediation analyses revealed that emotion dysregulation significantly explained the relationship between childhood emotional abuse and AN symptomatology, and mediation effects did not differ by AN subtype (i.e., restricting vs. binge-eating/purging). DISCUSSION Findings provide initial support for a model in which childhood emotional abuse precipitates emotion dysregulation and the development of AN. Future studies with longitudinal designs and control groups are necessary to examine the direction and specificity of these cross-sectional associations