A twin study of alcohol dependence, binge eating, and compensatory behaviors

Genetic and environmental influence on alcohol intent and alcohol sips among U.S. children-Effects across sex, race, and ethnicity

INTRODUCTION

Alcohol intent (the susceptibility to initiating alcohol use) and alcohol sips (the initiation of alcohol) in youth are a multifactorial puzzle with many components. This research aims to examine the connection between genetic and environmental factors across sex, race and ethnicity.

METHODS

Data was obtained from the twin hub of the Adolescent Brain Cognitive Development (ABCD) study at baseline (2016-2018). Variance component models were conducted to dissect the additive genetic (A), common (C) and unique environmental (E) effects on alcohol traits. The proportion of the total alcohol phenotypic variation attributable to additive genetic factors is reported as heritability (h2).

RESULTS

The sample (n = 1,772) included an approximately equal male-female distribution. The 886 same-sex twin pairs were 60.4% dizygotic (DZ), 39.6% monozygotic (MZ), 65.4% non-Hispanic Whites, 13.9% non-Hispanic Blacks, 10.8% of Hispanics with a mean age of 121.2 months. Overall, genetic predisposition was moderate for alcohol intent (h2 = 28%, p = .006) and low for alcohol initiation (h2 = 4%, p = 0.83). Hispanics (h2 = 53%, p < .0001) and Blacks (h2 = 48%, p < .0001) demonstrated higher alcohol intent due to additive genetic factors than Whites (h2 = 34%, p < .0001). Common environmental factors explained more variation in alcohol sips in females (c2 = 63%, p = .001) than in males (c2 = 55%, p = .003). Unique environmental factors largely attributed to alcohol intent, while common environmental factors explained the substantial variation in alcohol initiation.

CONCLUSION

Sex and racial/ethnic disparities in genetic and environmental risk factors for susceptibility to alcohol initiation can lead to significant health disparities. Certain populations may be at greater risk for alcohol use due to their genetic and ecological factors at an early age.

Associations of broad eating disorder symptoms with later alcohol problems in Finnish adult twins: A nationwide 10-year follow-up

OBJECTIVE

Eating disorders are associated with subsequent alcohol problems, but it is not known whether this association also extends to broader eating disorder symptoms not captured by clinical diagnoses. We assessed the longitudinal association of broad eating disorder symptoms with alcohol problems in a nationwide twin sample (FinnTwin16).

METHODS

Finnish women (N = 1905) and men (N = 1449) self-reported their eating disorder symptoms using the Eating Disorder Inventory-2 Bulimia, Drive for Thinness, and Body Dissatisfaction subscales at the mean age of 24.4 years in 2000-2003. A subsample of participants also completed items on drive for muscularity, height dissatisfaction, and muscle-enhancing supplement use. Alcohol problems were assessed 10 years later at the age of 34.1 in 2010-2012 with the Rutgers Alcohol Problem Index.

RESULTS

Eating disorder symptoms were associated with later alcohol problems (odds ratio per point increase 1.02-1.18). Bulimia showed stronger associations among men than women (p for interaction .012). Drive for muscularity and height dissatisfaction were also associated with later alcohol problems, but supplement use was not. When accounting for baseline alcohol problems, only Bulimia (among women and men) and Drive for Thinness (among men) were significantly associated with later alcohol problems. Bulimia was also significantly associated with later alcohol problems in within-twin-pair analyses among dizygotic twins, but not among monozygotic twins.

DISCUSSION

In a longitudinal setting, eating disorder symptoms were associated with later alcohol problems. Bulimic symptoms were a stronger risk factor for men than women. These associations may be attributable to baseline alcohol problems, childhood environment and genetic liability.

PUBLIC SIGNIFICANCE

This study found that both young adult women and men with broad eating disorder symptoms are at a higher risk of alcohol-related problems than those without such symptoms. Men with bulimic symptoms were at a particularly high risk. These findings emphasize the need for better prevention and treatment of disordered eating, body image concerns and alcohol problems for both young adult women and men.

Differential genetic associations between dimensions of eating disorders and alcohol involvement in late adolescent twins

BACKGROUND

Twin studies have demonstrated shared genetic and environmental effects between eating disorders and alcohol involvement in adults and middle adolescents. However, fewer studies have focused on late adolescents or investigated a wide range of eating disorder dimensions and alcohol involvement subscales in both sexes. We examined genetic and environmental correlations among three eating disorder dimensions and two alcohol involvement subscale scores in late adolescent twins using bivariate twin models.

METHODS

Participants were 3568 female and 2526 male same-sex twins aged 18 years old from the Child and Adolescent Twin Study in Sweden. The Eating Disorder Inventory-2 (EDI) assessed the drive for thinness, bulimia, and body dissatisfaction. Alcohol involvement was assessed with the Alcohol Use Disorder Identification Test consumption (AUDIT-C) and problem (AUDIT-P) subscales.

RESULTS

Only phenotypic and twin correlations in female twins met our threshold for twin modeling. The proportion of total variance for each trait accounted for by additive genetic factors ranged from 0.50 to 0.64 in female twins, with the rest explained by nonshared environmental factors and measurement error. Shared environmental factors played a minimal role in the variance of each trait. The strongest genetic correlation (ra ) emerged between EDI bulimia and AUDIT-P (ra  = 0.46, 95% confidence interval: 0.37, 0.55), indicating that the proportion of genetic variance of one trait that was shared with the other trait was 0.21. Nonshared environmental correlations between eating disorder dimensions and alcohol involvement ranged from 0.03 to 0.13.

CONCLUSIONS

We observed distinct patterns of genetic and environmental effects for co-occurring eating disorder dimensions and alcohol involvement in female vs. male twins, supporting sex-specific treatment strategies for late adolescents with comorbid eating disorders and alcohol use disorder. Our findings emphasize the importance of assessing family history of multiple eating disorder dimensions while treating late adolescents with problematic alcohol use, and vice versa, to improve detection and treatment.

The Relationship between Binge Drinking and Binge Eating in Adolescence and Youth: A Systematic Review and Meta-Analysis

Adolescence and youth are critical periods in which alcohol consumption is usually initiated, especially in the form of binge drinking. In recent years, it is increasingly common to find adolescents and young people who also present binge behaviors towards unhealthy food with the aim of alleviating their anxiety (emotional eating) and/or because of impulsive personality. Despite the social and health relevance of this issue, it remains scarcely studied and more preventive research needs to be developed. Our meta-analysis study aimed to evaluate the relationship and co-occurrence of both binge behaviors during adolescence and young adulthood to clarify the link between binge drinking and eating. Selective literature search on different online databases was performed. We identified discrete but significant results regarding the direct association between binge drinking and binge eating in correlation coefficients and odds ratio. Future research should focus on the common psychological background and motives behind these problematic behaviors owing to their clinical implications for effective prevention and treatment.

The Differential Heritability of Social Adjustment by Sex

Sex differences in social adjustment are frequently observed; however, there has been very little research on adaptability in the individual and social domains. The aim of this study was to investigate the sex difference in social abilities, such as high self-appeal, sociability, school adaptation, and home adaptation between school-age males and females. The sample for this study included both same-sex and opposite-sex twin pairs: a total of 467 twin pairs. We classified them into three groups: a group of those in lower classes of elementary school, a group of those in higher classes of elementary school, and a group of those in junior high school. The heritability of school adaptation was estimated to be 95% in males and 54% in females in the junior high school group. The full sex-limitation model showed a better fit in this group, and this means that a qualitative genetic difference exists. For school adaptation, there was no sex difference in lower elementary school classes; however, a quantitative difference appeared in higher classes of elementary school. Moreover, a qualitative difference appeared in junior high school. From this research, it became clear that sex differences in heritability exist for school adaptation, and there was a marked increase from the elementary school children to the junior high school children.

Blockade of Orexin Receptors in the Posterior Paraventricular Nucleus of the Thalamus Prevents Stress-Induced Reinstatement of Reward-Seeking Behavior in Rats With a History of Ethanol Dependence

Neural systems involved in processing natural rewards and drugs of abuse overlap and exposure to drugs of abuse induce neuroadaptations that can cause compulsive-like behavior. For example, the recruitment of the orexin (Orx) system by drugs of abuse has been proposed to induce neuroadaptations that in turn alter its function, reflected by maladaptive, compulsive, and addictive behavior. Orexin neurons project to the paraventricular nucleus of the thalamus (PVT)—particularly the posterior part (pPVT), a structure that plays a key role in stress regulation. This study investigated whether Orx transmission in the pPVT plays a role in stress-induced reinstatement of reward-seeking behavior toward ethanol (EtOH) and a highly palatable food reward [sweetened condensed milk (SCM)] in rats and whether this role changes with EtOH dependence. After being trained to orally self-administer EtOH or SCM, the rats were made dependent (EtOH_D and SCM_D) by chronic intermittent EtOH vapor exposure. The control nondependent groups (EtOH_ND and SCM_ND) were exposed to air. Following extinction, the rats were tested for stress-induced reinstatement of EtOH- and SCM-seeking behavior. Stress reinstated EtOH- and SCM-seeking behavior in all groups (EtOH_D/ND and SCM_D/ND). Administration of the dual Orx receptor (OrxR) antagonist TCS1102 (15 μg) in the pPVT prevented stress-induced reinstatement only in dependent rats (EtOH_D and SCM_D). In parallel, the qPCR analysis showed that Orx mRNA expression in the hypothalamus and OrxR1/R2 mRNA expression in the pPVT were increased at the time of testing in the EtOH_D and SCM_D groups. These results are the first to implicate Orx transmission in the pPVT in the stress-induced reinstatement of reward-seeking behavior in EtOH dependent rats and indicate the maladaptive recruitment of Orx transmission in the pPVT by EtOH dependence.

Impulsivity and anxiety-related dimensions in adults with bulimic-spectrum disorders differentially relate to eating disordered behaviors

While facets of both anxiety and impulsivity appear central to the development and maintenance of bulimia nervosa (BN), specific BN behaviors may be propagated by differing profiles of risk. The current study examined associations between dimensions of anxiety and impulsivity and BN symptoms (binge eating, vomiting, laxative misuse, driven exercise), both in terms of the presence of such behaviors and their frequency. Two hundred and four women (M_age = 25.7 years) who met DSM-IV criteria for full or subthreshold BN completed self-report measures of perfectionism (Frost Multidimensional Perfectionism Scale), anxiety (Spielberger Trait Anxiety Inventory), impulsivity (Barratt Impulsiveness Scale-11; Impulsive Behavior Scale), eating disordered behaviors (Eating Disorder Examination - Questionnaire), and associated psychiatric symptoms (Michigan Assessment Screening Test/Alcohol-Drug; Maudsley Obsessive-Compulsive Inventory). Factor analysis revealed multidimensional impulsive and anxiety-related traits (5 anxiety-related factors; 7 impulsivity-related factors). In zero-sensitive regression models, different facets of impulsivity evidenced association with the presence of binge eating (risk taking), laxative misuse (impulsive spending), and fasting (difficulty concentrating), along with the frequency of vomiting (long-term planning difficulties). In contrast, anxiety-related dimensions were only associated with driven exercise (high standards) and fasting (concern over mistakes, high standards, parental expectations). Overall, impulsive and anxiety-related factors and symptoms showed distinct associations with specific eating disorder behaviors, even among those with the same diagnosis.

Dialectical behaviour therapy skills training for the treatment of addictive behaviours among individuals with alcohol use disorder: the effect of emotion regulation and experiential avoidance

BACKGROUNDS

Dialectical behavior therapy skills training (DBT-ST) is an effective treatment for alcohol use disorder (AUD). AUD frequently co-occurs with other addictive behaviors.

OBJECTIVE

s: These secondary analyses of prior studies on the effectiveness of a 3-month DBT-ST program for AUD investigated pre- post-treatment changes in the severity of concurrent addictive behaviors. The study hypothesized that emotion regulation and experiential avoidance should be the key therapeutic mechanisms involved in the treatment of addictive behaviors.

METHODS

The research included 186 individuals (110 males; 76 females) with a primary diagnosis of AUD. Mediational models were performed considering shorter PROMIS questionnaire subscales (i.e., gambling, sex, shopping, food binging, and starvation) as dependent variables. The difficulties in emotion regulation scale and acceptance and action questionnaire-II total scores were independent and mediator variables, respectively.

RESULTS

Clinical variables significantly improved during the treatment, independent of baseline levels. Changes in emotion regulation showed significant total effects on improvements in addictive behaviors. Significant indirect effects of changes in experiential avoidance were detected considering compulsive buying and dysfunctional eating behaviors.

CONCLUSION

The DBT-ST was a feasible treatment for several addictive behaviors frequently reported by individuals with AUD. The improvements in emotion regulation and experiential avoidance were relevant therapeutic mechanisms involved in the treatment of these conditions. Future controlled trials and follow-up studies are recommended to support the efficacy of DBT-ST as a stand-alone intervention for the treatment of different classes of addictive behaviors.

Genetics of Eating Disorders: What the Clinician Needs to Know

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

Alcohol Use and Disordered Eating in a US Sample of Heterosexual and Sexual Minority Adolescents

OBJECTIVE

To expand knowledge of co-occurring alcohol use and disordered eating behaviors (DEB) among sexual minority (ie, nonheterosexual) youth.

METHOD

Using pooled 2009 to 2015 US Youth Risk Behavior Surveys (322,687 students; 7.3% lesbian, gay, bisexual), multivariable logistic regression models examined the following: (1) associations of age of onset of drinking and past month binge drinking with past year DEB (fasting, diet pill use, purging, steroid use); and (2) effect modification by sexual orientation.

RESULTS

Alcohol use and sexual minority identity were independently associated with elevated odds for diet pill use and purging among female adolescents, and with fasting and steroid use among male adolescents. Odds of fasting increased with greater frequency of monthly binge drinking among heterosexual adolescent female youth, and odds of diet pill use increased with greater frequency of monthly binge drinking among heterosexual adolescent male youth. DEB prevalence was particularly pronounced among adolescents who binge drank and who were not sure of their sexual orientation identity. Among male adolescents not sure of their sexual orientation identity, those who binge drank more than 1 day in the past month had 8.63 to 23.62 times the odds of using diet pills relative to those who did not binge drink, and 13.37 to 26.42 times the odds of purging relative to those who did not binge drink.

CONCLUSION

More research is needed on psychosocial factors underlying alcohol use and DEB in youth of all sexual orientations.

Illicit Drug Use, Cigarette Smoking, and Eating Disorder Symptoms: Associations in an Adolescent Twin Sample

OBJECTIVE

Twin studies have shown that genetic factors in part explain the established relation between alcohol use (i.e., problematic use or abuse/dependence) and eating disorder symptoms in adolescent and adult females. However, studies have yet to elucidate if there are similar shared genetic factors between other aspects of substance involvement, such as illicit drug use and repeated cigarette smoking.

METHOD

For those sex-specific phenotypic correlations above our threshold of .20, we used a behavioral genetic design to examine potential shared genetic overlap between self-reported lifetime illicit drug use and repeated cigarette smoking and the eating disorder symptoms of drive for thinness (DT), bulimia (BU), and body dissatisfaction (BD), as assessed with the Eating Disorder Inventory-II, in 16- to 17-year-old female and male twin pairs.

RESULTS

Only phenotypic correlations with illicit drug use met our threshold for twin modeling. Small to moderate genetic correlations were observed between illicit drug use and BU in both girls and boys and between illicit drug use and DT in girls.

CONCLUSIONS

Similar etiological factors are at play in the overlap between illicit drug use and certain eating disorder symptoms in girls and boys during adolescence, such that genetic factors are important for covariance. Specifically, illicit drug use was associated with bulimia nervosa symptoms in girls and boys, which parallels previous substance use research finding a genetic overlap between alcohol use and bulimia nervosa symptoms. Future research should prospectively examine developmental trajectories to further understand the etiological overlap between substance involvement and eating disorder symptoms.

The Lifespan Human Connectome Project in Aging: An overview

The original Human Connectome Project yielded a rich data set on structural and functional connectivity in a large sample of healthy young adults using improved methods of data acquisition, analysis, and sharing. More recent efforts are extending this approach to include infants, children, older adults, and brain disorders. This paper introduces and describes the Human Connectome Project in Aging (HCP-A), which is currently recruiting 1200 + healthy adults aged 36 to 100+, with a subset of 600 + participants returning for longitudinal assessment. Four acquisition sites using matched Siemens Prisma 3T MRI scanners with centralized quality control and data analysis are enrolling participants. Data are acquired across multimodal imaging and behavioral domains with a focus on factors known to be altered in advanced aging. MRI acquisitions include structural (whole brain and high resolution hippocampal) plus multiband resting state functional (rfMRI), task fMRI (tfMRI), diffusion MRI (dMRI), and arterial spin labeling (ASL). Behavioral characterization includes cognitive (such as processing speed and episodic memory), psychiatric, metabolic, and socioeconomic measures as well as assessment of systemic health (with a focus on menopause via hormonal assays). This dataset will provide a unique resource for examining how brain organization and connectivity changes across typical aging, and how these differences relate to key characteristics of aging including alterations in hormonal status and declining memory and general cognition. A primary goal of the HCP-A is to make these data freely available to the scientific community, supported by the Connectome Coordination Facility (CCF) platform for data quality assurance, preprocessing and basic analysis, and shared via the NIMH Data Archive (NDA). Here we provide the rationale for our study design and sufficient details of the resource for scientists to plan future analyses of these data. A companion paper describes the related Human Connectome Project in Development (HCP-D, Somerville et al., 2018), and the image acquisition protocol common to both studies (Harms et al., 2018).

Associations Between Alcohol Involvement and Drive for Thinness and Body Dissatisfaction in Adolescent Twins: A Bivariate Twin Study

BACKGROUND

Alcohol involvement has familial associations with bulimic symptoms (i.e., binge eating, inappropriate compensatory behaviors), with several studies indicating a genetic overlap between the two. It is unclear whether overlapping familial risk with alcohol involvement extends to other eating disorder symptoms. Understanding the genetic overlap between alcohol involvement and other eating disorder symptoms may aid in more targeted interventions for comorbid alcohol use-eating disorder symptoms. Thus, we investigated associations between alcohol involvement and 2 core eating disorder symptoms: drive for thinness and body dissatisfaction in adolescent female and male twins.

METHODS

We assessed 3 levels of alcohol involvement: alcohol use in the last month, having ever been intoxicated, and alcohol intoxication frequency via self-report. The Eating Disorder Inventory-II assessed drive for thinness and body dissatisfaction. Sex-specific biometrical twin modeling examined the genetic overlap between alcohol involvement and eating disorder symptoms.

RESULTS

Phenotypic associations between alcohol involvement, drive for thinness, and body dissatisfaction were significantly greater in girls compared with boys. A majority of the associations between alcohol involvement, drive for thinness, and body dissatisfaction in girls, but not boys, met our threshold for twin modeling (phenotypic r > 0.20). Moderate genetic correlations were observed between the 3 aspects of alcohol involvement and drive for thinness. Moderate genetic correlations were observed between alcohol use and intoxication frequency and body dissatisfaction.

CONCLUSIONS

Together with the literature on alcohol involvement and bulimic symptoms, these findings suggest a generalized association between alcohol involvement and eating disorder symptoms in girls, whereas this association may be symptom specific in boys. Genetic correlations indicate that the amount and direction of this genetic overlap differs across specific symptoms. When intervening on comorbid alcohol involvement and eating disorder symptoms, it may be important to target-specific eating disorder symptoms.

Shared familial risk between bulimic symptoms and alcohol involvement during adolescence

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

Genome-wide association study of alcohol consumption and genetic overlap with other health-related traits in UK Biobank (N=112 117)

Alcohol consumption has been linked to over 200 diseases and is responsible for over 5% of the global disease burden. Well-known genetic variants in alcohol metabolizing genes, for example, ALDH2 and ADH1B, are strongly associated with alcohol consumption but have limited impact in European populations where they are found at low frequency. We performed a genome-wide association study (GWAS) of self-reported alcohol consumption in 112 117 individuals in the UK Biobank (UKB) sample of white British individuals. We report significant genome-wide associations at 14 loci. These include single-nucleotide polymorphisms (SNPs) in alcohol metabolizing genes (ADH1B/ADH1C/ADH5) and two loci in KLB, a gene recently associated with alcohol consumption. We also identify SNPs at novel loci including GCKR, CADM2 and FAM69C. Gene-based analyses found significant associations with genes implicated in the neurobiology of substance use (DRD2, PDE4B). GCTA analyses found a significant SNP-based heritability of self-reported alcohol consumption of 13% (se=0.01). Sex-specific analyses found largely overlapping GWAS loci and the genetic correlation (rG) between male and female alcohol consumption was 0.90 (s.e.=0.09, P-value=7.16 × 10^-23). Using LD score regression, genetic overlap was found between alcohol consumption and years of schooling (rG=0.18, s.e.=0.03), high-density lipoprotein cholesterol (rG=0.28, s.e.=0.05), smoking (rG=0.40, s.e.=0.06) and various anthropometric traits (for example, overweight, rG=-0.19, s.e.=0.05). This study replicates the association between alcohol consumption and alcohol metabolizing genes and KLB, and identifies novel gene associations that should be the focus of future studies investigating the neurobiology of alcohol consumption.

Phenotypic and Genetic Relationship Between BMI and Drinking in a Sample of UK Adults

The health impairments derived from both alcoholism and obesity are well known. However, reports that relate increased alcohol use with increased measures of obesity have been mixed in their findings, especially with respect to genetic factors that could potentially link these two behaviors. Here, using a large sample of adults from the UK (n ≈ 113,000), we report both the observed and genetic correlations between BMI (kg/m2) and two measures of alcohol use: reported quantity (drinks per week) and frequency of use (from never to daily). Overall, both observationally and genetically, alcohol intake is negatively correlated with BMI. Phenotypic correlations ranged from -0.01 to -0.17, and genetic correlations ranged from -0.1 to -0.4. Genetic correlations tended to be stronger than the phenotypic correlations, and these correlations were stronger in females and between BMI and, specifically, frequency of use. Though the mechanisms driving these relationships are yet to be identified, we can conclude that the genetic factors related to drinking both more and more often are shared with those responsible for lower BMI.

An examination of affect prior to and following episodes of getting drunk in women with bulimia nervosa

The current study examined the association between affect and self-reported alcohol intoxication in women with bulimia nervosa (BN; N=133). Participants completed a two-week ecological momentary assessment protocol. Momentary global positive affect (PA) and negative affect (NA), as well as the facets of NA (fear, guilt, hostility and sadness), were measured. Forty-five participants endorsed that they "got drunk" during the study period. Daily mean and variability of global PA and NA were compared between days with self-reported alcohol intoxication and days without self-reported alcohol intoxication. Trajectories of affect were modeled prior to and following episodes of self-reported alcohol intoxication. There were no differences in the mean or variability of PA or NA on days characterized by self-reported alcohol intoxication compared to days with no self-reported alcohol intoxication (ps>0.05). PA decreased significantly prior to self-reported alcohol intoxication and remained stable afterwards. There were no changes in global NA before or after self-reported alcohol intoxication, but an examination of the facets of NA showed that sadness increased following episodes of self-reported alcohol intoxication. These findings showed only partial support for a negative reinforcement model of alcohol use in women with BN.

Risky drinking behaviors among women with eating disorders-A longitudinal community-based study

OBJECTIVE

Eating disorders and alcohol use disorders often co-occur, but few prospective studies have examined their relationship. Using a large population-based twin sample, we investigated how the drinking behaviors of women with lifetime eating disorders unfold from adolescence to adulthood.

METHOD

We identified 182 women with a lifetime eating disorder assessed at mean age 24, including 92 women with DSM-5 anorexia nervosa and 58 women with DSM-5 bulimia nervosa, from the 1975-1979 birth cohorts of Finnish twins (N = 2,825 women). Frequency of drinking and intoxicating were assessed at ages 16, 24, and 34. Drinking problems were assessed at ages 24 and 34 by the Malmö-modified Michigan Alcohol Screening Test (Mm-Mast) and the Rutgers Alcohol Problem Index (RAPI).

RESULTS

At age 16, proportionately more women with eating disorders reported being severely intoxicated when they last drank (25% vs.16%, P = 0.001), and at both surveys in adulthood, they reported more frequent intoxication and more alcohol-related problems than their unaffected peers. Those who had recovered from their eating disorder at age 24 still reported more alcohol-related problems in their 30s than did other women. The age of drinking onset, number of monthly drinking days, or frequency of intoxication in adolescence did not differ between women with lifetime eating disorders and unaffected women.

DISCUSSION

Women with eating disorders scored higher than their unaffected peers on scales measuring alcohol dependence, alcohol-related problems, and intoxication. These differences persisted from mid-adolescence into young adulthood. Women with eating disorders should be assessed routinely for drinking behaviors. © 2016 Wiley Periodicals, Inc. (Int J Eat Disord 2016; 49:563-571).

Genetic and environmental components to self-induced vomiting

OBJECTIVE

We examined the association between the genetic and environmental factors contributing to the liability to having ever engaged in self-induced vomiting (SIV initiation) and the genetic and environmental factors contributing to regular SIV behaviors (weekly or daily) for weight control.

METHOD

SIV was assessed in 3,942 women from monozygotic twin pairs and 2,790 women from same-sex dizygotic twin pairs, aged 20-47, from the Swedish Twin study of Adults: Genes and Environment. A causal-contingent-common pathway model assessed the extent to which genetic and environmental factors that influence initiation of SIV also influence regular SIV behaviors.

RESULTS

In the best-fit model, genetic and individual-specific environmental factors influenced liability to SIV initiation. The genetic factors influencing regular SIV behaviors were the same as the genetic factors influencing SIV initiation. Additional individual-specific environmental factors that were unrelated to SIV initiation influenced regular SIV behaviors.

DISCUSSION

Our findings provide evidence that the underlying liabilities for SIV initiation and regular SIV lie on the same continuum given the degree of overlap in risk between SIV initiation and regular SIV behaviors. Further, the lack of specific genetic factors and the importance of individual-specific environmental factors for regular SIV behaviors highlight the significance of environmental factors in the etiology of eating disorder symptomatology and the non-deterministic nature of genetic factors. Finally, our results suggest that when it comes to preventing individuals from developing regular SIV behavior, intervening at an environmental level is warranted.

A Primer on the Genetics of Comorbid Eating Disorders and Substance Use Disorders

Eating disorders (EDs) and substance use disorders (SUDs) frequently co-occur; however, the reasons for this are unclear. We review the current literature on genetic risk for EDs and SUDs, as well as preliminary findings exploring whether these classes of disorders have overlapping genetic risk. Overall, genetic factors contribute to individual differences in liability to multiple EDs and SUDs. Although initial family studies concluded that no shared familial (which includes genetic) risk between EDs and SUDs exists, twin studies suggest a moderate proportion of shared variance is attributable to overlapping genetic factors, particularly for those EDs characterized by binge eating and/or inappropriate compensatory behaviours. No adoption or molecular genetic studies have examined shared genetic risk between these classes of disorders. Research investigating binge eating and inappropriate compensatory behaviours using emerging statistical genetic methods, as well as examining gene-environment interplay, will provide important clues into the aetiology of comorbid EDs and SUDs.

Prevalence of and familial influences on purging disorder in a community sample of female twins

OBJECTIVE

Purging disorder (PD) was recently included as an otherwise specified feeding or eating disorder (OSFED) in the DSM-5; however, limited information is available on its prevalence, and its etiology is unknown.

METHOD

Data from 1,790 monozygotic and 1,440 dizygotic European American female twins (age range = 18-29 years) from the Missouri Adolescent Female Twin Study were used to investigate prevalence and familial influences for PD. A structured clinical interview assessed lifetime DSM-IV criteria for eating disorders and PD. After adjustment for age, twin correlations and biometrical twin models were used to estimate familial (i.e., genetic plus shared environmental) influences on PD.

RESULTS

One hundred and twenty one (3.77%; 95% CI: 3.14, 4.49) women met criteria for lifetime PD. Twin correlations suggested that genetic, shared environmental, and nonshared environmental factors influenced liability to PD. Nonshared environmental factors accounted for 56% [35%, 79%] of the variance in PD. Although familial effects accounted for a significant proportion of variance (44% [21%, 65%]), it was not possible to disentangle the independent contributions of additive genetic effects (20% [0%, 65%]) and shared environmental effects (24% [0%, 57%]).

DISCUSSION

PD is a prevalent form of eating pathology. Familial factors are relevant to the development of PD but do not demonstrate the magnitude of heritable factors found for other eating disorders.

Genetic overlap between alcohol use disorder and bulimic behaviors in European American and African American women

BACKGROUND

Despite substantial evidence that alcohol use disorder (AUD) and bulimic behaviors (i.e., binge eating and compensatory behaviors) co-occur, insufficient information exists regarding a possible shared etiology. Moreover, although numerous twin studies of European ancestry individuals have reported moderate heritability estimates for AUD and bulimic behaviors, with little evidence for shared environmental factors, research on genetic and environmental risk in African American (AA) individuals is lacking.

METHODS

We investigated specific and overlapping genetic and environmental influences on AUD and bulimic behaviors in 3232 European American (EA; 55.38% monozygotic) and 549 AA (42.81% monozygotic) young adult female twins from the Missouri Adolescent Female Twin Study (age range=18-29 years). A structured clinical interview assessed lifetime DSM-5 AUD (minus craving) and bulimic behaviors. Biometrical twin modeling was conducted to generate age-adjusted estimates of genetic and environmental influences on AUD, bulimic behaviors, and their comorbidity.

RESULTS

Estimates of genetic and environmental contributions on AUD and bulimic behaviors could be equated across EA and AA women. Additive genetic effects accounted for 59% (95% CI: 50%, 66%) and 43% (33%, 52%) of the variance in AUD and bulimic behaviors, respectively, with the remainder due to non-shared environmental effects. Shared genetic factors (rg=.33 (.18, .49)) were solely responsible for the correlation between phenotypes; the non-shared environmental correlation was not significant (re=.10 (-.05, .25)).

CONCLUSIONS

Findings indicate similar magnitudes of genetic and environmental effects on AUD and bulimic behaviors for EA and AA women and implicate common genetic mechanisms underlying liability to these problem behaviors.

Smoking, alcohol consumption, and drug use among adolescents with psychiatric disorders compared with a population based sample

This study investigated frequencies of smoking, alcohol use, and illicit drug use by diagnostic category in 566 adolescent psychiatric patients, comparing this sample with 8173 adolescents from the general population in Norway who completed the Young-HUNT 3 survey. Frequencies of current alcohol use were high in both samples but were lower among psychiatric patients. Compared with adolescents in the general population, adolescents in the clinical sample had a higher prevalence of current smoking and over four times higher odds of having tried illicit drugs. In the clinical sample, those with mood disorders reported the highest frequencies of smoking, alcohol use, and illicit drug use, whereas those with autism spectrum disorders reported the lowest frequencies. Our results show an increased prevalence of risky health behaviors among adolescents with psychiatric disorders compared with the general population. The awareness of disorder-specific patterns of smoking and substance use may guide preventive measures.

Preliminary evidence for the role of HTR2A variants in binge eating in young women

We examined the association between 15 single nucleotide polymorphisms (SNPs) in HTR2A and characteristics of disordered eating, including weight/shape concerns, binge eating (with or without loss of control), and compensatory behaviors (purging and nonpurging). Whether a lifetime history of major depressive disorder (MDD) moderated or mediated this association was also investigated. A sample of 1533 twin women of White descent that were part of the Missouri Adolescent Female Twin Study was used. Data were collected using self-report responses to a semistructured interview. Logistic regression analyses were used to examine the association between weight/shape concerns, binge eating, and compensatory behaviors and SNPs (where carriers of the minor allele were coded as 1). Two SNPs, rs6561333 and rs2296972, showed a protective influence against binge eating, with rs2296972 being significant at a trend level after application of the false discovery rate. The SNP was not associated with MDD nor did MDD moderate its putative relation with binge eating. Pending replication, our analyses provide preliminary evidence for intronic SNPs in HTR2A and their association with binge eating. Given the well-documented role of serotonergic dysfunction in eating psychopathology, this report warrants considerable further study.

Genetic and environmental factors underlying comorbid bulimic behaviours and alcohol use disorders: a moderating role for the dysregulated personality cluster?

Women with bulimia nervosa (BN) frequently have co-occurring alcohol use disorders (AUDs). Studies of shared genetic transmission of these disorders have been mixed. Personality heterogeneity among individuals with BN may explain discrepant findings. Cluster analysis has characterized women with BN in groups on the basis of personality profiles. One group, the Dysregulated cluster, characterized largely by behavioural disinhibition and emotional dysregulation may be more closely linked etiologically to AUDs. This study examined whether genetic associations between BN and AUDs are the strongest among the Dysregulated cluster. Symptoms of BN and AUDs were assessed in female twins at ages 17 and 25 years from the Minnesota Twin Family Study. Personality clusters were defined using the Multidimensional Personality Questionnaire. Twin moderation models suggested small-to-moderate common genetic transmission between BN and AUDs. However, shared genetic effects did not differ by personality cluster. Findings suggest that personality clusters are unlikely to account for inconsistent findings regarding their shared aetiology.

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

Aspects of disordered eating and personality traits, such as neuroticism, are correlated and individually heritable. We examined the phenotypic correlation between binge eating episodes and indices of personality (neuroticism, extraversion, openness to experience, agreeableness, conscientiousness, and control/impulsivity). For correlations ≥|0.20|, we estimated the extent to which genetic and environmental factors contributed to this correlation. Participants included 3,446 European American same-sex female twins from the Missouri Adolescent Female Twin Study (median age = 22 years). Binge eating episode was assessed via interview questions. Personality traits were assessed by self-report questionnaires. There was a significant moderate phenotypic correlation between binge eating episode and neuroticism (r = 0.33) as well as conscientiousness (r = -0.21), while other correlations were significant but smaller (r ranging from -0.14 to 0.14). Individual differences in binge eating episodes, neuroticism, and conscientiousness were attributed to additive genetic influences (38% [95% CI: 21-53%], 45% [95% CI: 38-52%], and 44% [95% CI: 0.33-0.55%] respectively), with the remaining variance attributed to individual-specific environmental influences. Covariance was attributable to genetic (neuroticism r g = 0.37; conscientiousness r g = -0.22) and individual-specific environmental (neuroticism r e = 0.28; conscientiousness r e = -0.19) influences. Personality traits may be an early indicator of genetic vulnerability to a variety of pathological behaviors, including binge eating episode. Furthermore, prior research documenting phenotypic correlations between eating disorder diagnoses and personality may have stemmed from etiological overlap between these personality traits and aspects of disordered eating, such as binge eating episode.