Analysis of shared heritability in common disorders of the brain

Disorders of the brain can exhibit considerable epidemiological comorbidity and often share symptoms, provoking debate about their etiologic overlap. We quantified the genetic sharing of 25 brain disorders from genome-wide association studies of 265,218 patients and 784,643 control participants and assessed their relationship to 17 phenotypes from 1,191,588 individuals. Psychiatric disorders share common variant risk, whereas neurological disorders appear more distinct from one another and from the psychiatric disorders. We also identified significant sharing between disorders and a number of brain phenotypes, including cognitive measures. Further, we conducted simulations to explore how statistical power, diagnostic misclassification, and phenotypic heterogeneity affect genetic correlations. These results highlight the importance of common genetic variation as a risk factor for brain disorders and the value of heritability-based methods in understanding their etiology.

Genome-wide association study identifies eight risk loci and implicates metabo-psychiatric origins for anorexia nervosa

Characterized primarily by a low body-mass index, anorexia nervosa is a complex and serious illness1, affecting 0.9-4% of women and 0.3% of men2-4, with twin-based heritability estimates of 50-60%5. Mortality rates are higher than those in other psychiatric disorders6, and outcomes are unacceptably poor7. Here we combine data from the Anorexia Nervosa Genetics Initiative (ANGI)8,9 and the Eating Disorders Working Group of the Psychiatric Genomics Consortium (PGC-ED) and conduct a genome-wide association study of 16,992 cases of anorexia nervosa and 55,525 controls, identifying eight significant loci. The genetic architecture of anorexia nervosa mirrors its clinical presentation, showing significant genetic correlations with psychiatric disorders, physical activity, and metabolic (including glycemic), lipid and anthropometric traits, independent of the effects of common variants associated with body-mass index. These results further encourage a reconceptualization of anorexia nervosa as a metabo-psychiatric disorder. Elucidating the metabolic component is a critical direction for future research, and paying attention to both psychiatric and metabolic components may be key to improving outcomes.

Significant Locus and Metabolic Genetic Correlations Revealed in Genome-Wide Association Study of Anorexia Nervosa

OBJECTIVE

The authors conducted a genome-wide association study of anorexia nervosa and calculated genetic correlations with a series of psychiatric, educational, and metabolic phenotypes.

METHOD

Following uniform quality control and imputation procedures using the 1000 Genomes Project (phase 3) in 12 case-control cohorts comprising 3,495 anorexia nervosa cases and 10,982 controls, the authors performed standard association analysis followed by a meta-analysis across cohorts. Linkage disequilibrium score regression was used to calculate genome-wide common variant heritability (single-nucleotide polymorphism [SNP]-based heritability [h2SNP]), partitioned heritability, and genetic correlations (rg) between anorexia nervosa and 159 other phenotypes.

RESULTS

Results were obtained for 10,641,224 SNPs and insertion-deletion variants with minor allele frequencies >1% and imputation quality scores >0.6. The h2SNP of anorexia nervosa was 0.20 (SE=0.02), suggesting that a substantial fraction of the twin-based heritability arises from common genetic variation. The authors identified one genome-wide significant locus on chromosome 12 (rs4622308) in a region harboring a previously reported type 1 diabetes and autoimmune disorder locus. Significant positive genetic correlations were observed between anorexia nervosa and schizophrenia, neuroticism, educational attainment, and high-density lipoprotein cholesterol, and significant negative genetic correlations were observed between anorexia nervosa and body mass index, insulin, glucose, and lipid phenotypes.

CONCLUSIONS

Anorexia nervosa is a complex heritable phenotype for which this study has uncovered the first genome-wide significant locus. Anorexia nervosa also has large and significant genetic correlations with both psychiatric phenotypes and metabolic traits. The study results encourage a reconceptualization of this frequently lethal disorder as one with both psychiatric and metabolic etiology.

Breakfast skipping and health-compromising behaviors in adolescents and adults

OBJECTIVE

To investigate which sociodemographic factors and behaviors are associated with breakfast skipping in adolescents and adults.

DESIGN

Five birth cohorts of adolescent twins and their parents received an extensive behavioral and medical self-report questionnaire that also assessed breakfast-eating frequency.

SETTING

Finland, 1991-1995.

SUBJECTS

A population sample of 16-y-old girls and boys (n=5448) and their parents (n=4660).

RESULTS

Parental breakfast eating was the statistically most significant factor associated with adolescent breakfast eating. Smoking, infrequent exercise, a low education level at 16, female sex, frequent alcohol use, behavioral disinhibition, and high body mass index (BMI) were significantly associated with adolescent breakfast skipping. In adults, smoking, infrequent exercise, low education level, male sex, higher BMI, and more frequent alcohol use were associated with breakfast skipping. In the adult sample, older individuals had breakfast more often than younger ones. Both adults and adolescents who frequently skipped breakfast were much more likely to exercise very little compared to those who skipped breakfast infrequently. Breakfast skipping was associated with low family socioeconomic status in adults and adolescent boys, but not in girls. Breakfast skipping clustered moderately with smoking, alcohol use, and sedentary lifestyle in both adults and adolescents.

CONCLUSIONS

Breakfast skipping is associated with health-compromising behaviors in adults and adolescents. Individuals and families who skip breakfast may benefit from preventive efforts that also address risk behaviors other than eating patterns.

SPONSORSHIP

National Institute of Alcohol Abuse and Alcoholism (AA08315), Academy of Finland (44069), European Union Fifth Framework Program (QLRT-1999-00916), Yrjö Jahnsson Foundation, and Jalmari and Rauha Ahokas Foundation.

Epidemiology and course of anorexia nervosa in the community

OBJECTIVE

Most previous studies of the prevalence, incidence, and outcome of anorexia nervosa have been limited to cases detected through the health care system, which may bias our understanding of the disorder's incidence and natural course. The authors sought to describe the onset and outcomes of anorexia nervosa in the general population.

METHOD

Lifetime prevalences, incidence rates, and 5-year recovery rates of anorexia nervosa were calculated on the basis of data from 2,881 women from the 1975-1979 birth cohorts of Finnish twins. Women who screened positive for eating disorder symptoms (N=292), their screen-negative female co-twins (N=134), and 210 randomly selected screen-negative women were assessed for lifetime eating disorders by telephone by experienced clinicians. To assess outcomes after clinical recovery and to detect residua of illness, women who had recovered were compared with their unaffected co-twins and healthy unrelated women on multiple outcome measures.

RESULTS

The lifetime prevalence of DSM-IV anorexia nervosa was 2.2%, and half of the cases had not been detected in the health care system. The incidence of anorexia nervosa in women between 15 and 19 years of age was 270 per 100,000 person-years. The 5-year clinical recovery rate was 66.8%. Outcomes did not differ between detected and undetected cases. After clinical recovery, the residua of illness steadily receded. By 5 years after clinical recovery, most probands had reached complete or nearly complete psychological recovery and closely resembled their unaffected co-twins and healthy women in weight and most psychological and social measures.

CONCLUSIONS

The authors found a substantially higher lifetime prevalence and incidence of anorexia nervosa than reported in previous studies, most of which were based on treated cases. Most women recovered clinically within 5 years, and thereafter usually progressed toward full recovery.

A genome-wide association study of anorexia nervosa

Anorexia nervosa (AN) is a complex and heritable eating disorder characterized by dangerously low body weight. Neither candidate gene studies nor an initial genome-wide association study (GWAS) have yielded significant and replicated results. We performed a GWAS in 2907 cases with AN from 14 countries (15 sites) and 14 860 ancestrally matched controls as part of the Genetic Consortium for AN (GCAN) and the Wellcome Trust Case Control Consortium 3 (WTCCC3). Individual association analyses were conducted in each stratum and meta-analyzed across all 15 discovery data sets. Seventy-six (72 independent) single nucleotide polymorphisms were taken forward for in silico (two data sets) or de novo (13 data sets) replication genotyping in 2677 independent AN cases and 8629 European ancestry controls along with 458 AN cases and 421 controls from Japan. The final global meta-analysis across discovery and replication data sets comprised 5551 AN cases and 21 080 controls. AN subtype analyses (1606 AN restricting; 1445 AN binge-purge) were performed. No findings reached genome-wide significance. Two intronic variants were suggestively associated: rs9839776 (P=3.01 × 10(-7)) in SOX2OT and rs17030795 (P=5.84 × 10(-6)) in PPP3CA. Two additional signals were specific to Europeans: rs1523921 (P=5.76 × 10(-)(6)) between CUL3 and FAM124B and rs1886797 (P=8.05 × 10(-)(6)) near SPATA13. Comparing discovery with replication results, 76% of the effects were in the same direction, an observation highly unlikely to be due to chance (P=4 × 10(-6)), strongly suggesting that true findings exist but our sample, the largest yet reported, was underpowered for their detection. The accrual of large genotyped AN case-control samples should be an immediate priority for the field.

The process of recovery in eating disorder sufferers' own words: an Internet-based study

This exploratory Internet-based study attempts to understand what eating disorder sufferers suggest when they mention the word recovery. All messages (N = 685) posted in a Finnish-language eating disorders discussion group during a 3-month period were analyzed for the contexts of the word recovery using text analysis software and qualitative methods. The discussion group participants' views of recovery changed according to their current stage of change. Mentioning recovery was least likely during precontemplation and relapse. Internet discussion group was seen as helpful in the early stages of change, but as impeding recovery in the last stages. Willpower and ceasing to identify with eating disorders were viewed as essential to recovery. The value of professional help in recovery was viewed as conditional on the eating disorders sufferer's own willingness to change. Internet-based support groups have many potential therapeutic applications. Motivational aspects need to be taken into account in promoting recovery.

Incidence and outcomes of bulimia nervosa: a nationwide population-based study

BACKGROUND

Little is known about the epidemiology of bulimia nervosa outside clinical settings. We report the incidence, prevalence and outcomes of bulimia nervosa using for the first time a nationwide study design.

METHOD

To assess the incidence and natural course and outcomes of DSM-IV bulimia nervosa among women from the general population, women (n=2881) from the 1975-79 birth cohorts of Finnish twins were screened for lifetime eating disorders using a two-stage procedure consisting of a questionnaire screen and the Structured Clinical Interview for DSM-IV (SCID). Clinical recovery was defined as 1-year abstinence from bingeing and purging combined with a body mass index (BMI) 19 kg/m2.

RESULTS

The lifetime prevalence of DSM-IV bulimia nervosa was 2.3%; 76% of the women suffered from its purging subtype and 24% from the non-purging subtype. The incidence rate of bulimia nervosa was 300/100000 person-years at the peak age of incidence, 16-20 years, and 150/100000 at 10-24 years. The 5-year clinical recovery rate was 55.0%. Less than a third of the cases had been detected by health-care professionals; detection did not influence outcome. After clinical recovery from bulimia nervosa, the mean levels of residual psychological symptoms gradually decreased over time but many women continued to experience significantly more body image problems and psychosomatic symptoms than never-ill women.

CONCLUSIONS

Few women with bulimia nervosa are recognized in health-care settings. Symptoms of bulimia are relatively long-standing, and recovery is gradual. Many clinically recovered women experience residual psychological symptoms after attaining abstinence from bingeing and purging.

Worldwide prevalence of DSM-5 eating disorders among young people

PURPOSE OF REVIEW

Eating disorders (anorexia nervosa, bulimia nervosa, binge eating disorder, and other eating disorders) affect young people worldwide. This narrative review summarizes key studies conducted on the prevalence of Diagnostic and Statistical Manual of Mental Disorders (DSM-5) eating disorders among young people in 2013-22.

RECENT FINDINGS

In Western settings, a substantial proportion of young people have reported an eating disorder. Overall, 5.5--17.9% of young women and 0.6-2.4% of young men have experienced a DSM-5 eating disorder by early adulthood. Lifetime DSM-5 anorexia nervosa was reported by 0.8-6.3% of women and 0.1-0.3% of men, bulimia nervosa by 0.8-2.6% of women and 0.1-0.2% of men, binge eating disorder by 0.6-6.1% of women and 0.3-0.7% of men, other specified feeding or eating disorders by 0.6-11.5% of women and 0.2-0.3% of men, and unspecified feeding or eating disorders 0.2-4.7% of women and 0-1.6% of men. Gender and sexual minorities were at particularly high risk. Emerging studies from Eastern Europe, Asia, and Latin America show similar high prevalences. During the COVID-19 pandemic, the incidence of eating disorders has still increased.

SUMMARY

Eating disorders are a global health concern among young people. Improved detection, management, and prevention methods are urgently needed.

Binge eating disorder

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

Genetic epidemiology, endophenotypes, and eating disorder classification

OBJECTIVE

To explore how genetic epidemiology has informed the identification of endophenotypes and how endophenotypes may inform future classification of eating disorders.

METHOD

Literature review and synthesis.

RESULTS

Although a number of endo- and subphenotypes have been suggested for eating disorders, few reach the rigorous definitions developed for candidate endophenotypes.

CONCLUSION

Further study of endophenotypes and subphenotypes for eating disorders may assist with developing a more homogenous classification system that more closely reflects underlying biological mechanisms, and provides a clearer focus for the development of coherent models and treatments.

Do Disordered Eating Behaviours Have Long-term Health-related Consequences?

OBJECTIVE

Long-term health-related consequences of disordered eating behaviours of young adults remain poorly understood. We examined whether disordered eating behaviours in mid-20s are associated with physical and mental health 10 years later.

METHODS

Women (n = 2631) and men (n = 2394) from a population-based FinnTwin16 cohort were assessed using three subscales of the Eating Disorder Inventory-2 at age 24. Self-rated health, body mass index (BMI), waist circumference and psychological distress were assessed at age 24 and reassessed 10 years later.

RESULTS

In crude models, disordered eating behaviours at age 24 were associated cross-sectionally and prospectively with poor self-rated health, higher BMI, larger waist circumference and psychological distress in both sexes. In models adjusted for baseline BMI and potential confounders, disordered eating behaviours predicted increased psychological distress in both sexes and poor self-rated health in men.

CONCLUSIONS

Among young adults, disordered eating behaviours are associated with long-term health-related consequences, particularly psychological distress. Copyright © 2017 John Wiley & Sons, Ltd and Eating Disorders Association.

The DSM-5 diagnostic criteria for anorexia nervosa may change its population prevalence and prognostic value

The definition of anorexia nervosa was revised for the Fifth Edition of the Diagnostic and Statistical Manual (DSM-5). We examined the impact of these changes on the prevalence and prognosis of anorexia nervosa. In a nationwide longitudinal study of Finnish twins born 1975-1979, the women (N = 2825) underwent a 2-stage screening for eating disorders at mean age 24. Fifty-five women fulfilled DSM-IV criteria for lifetime anorexia nervosa. When we recoded the interviews using DSM-5 criteria, we detected 37 new cases. We contrasted new DSM-5 vs. DSM-IV cases to assess their clinical characteristics and prognosis. We also estimated lifetime prevalences and incidences and tested the association of minimum BMI with prognosis. We observed a 60% increase in the lifetime prevalence of anorexia nervosa using the new diagnostic boundaries, from 2.2% to 3.6%. The new cases had a later age of onset (18.8 y vs. 16.5, p = 0.002), higher minimum BMI (16.9 vs. 15.5 kg/m(2), p = 0.0004), a shorter duration of illness (one year vs. three years, p = 0.002), and a higher 5-year probability or recovery (81% vs. 67%, p = 0.002). Minimum BMI was not associated with prognosis. It therefore appears that the substantial increase in prevalence of anorexia nervosa is offset by a more benign course of illness in new cases. Increased diagnostic heterogeneity underscores the need for reliable indicators of disease severity. Our findings indicate that BMI may not be an ideal severity marker, but should be complemented by prognostically informative criteria. Future studies should focus on identifying such factors in prospective settings.

Body dissatisfaction and drive for thinness in young adult twins

OBJECTIVE

We explored correlates of the Eating Disorder Inventory subscales Body Dissatisfaction (BD) and Drive for Thinness (DT) and genetic and environmental influences on these traits.

METHOD

In a population-based sample of 4,667 Finnish twins aged 22-27 years, we conducted twin modeling to explore genetic and environmental contributions to body dissatisfaction and drive for thinness. Logistic regression was used for the correlational analysis.

RESULTS

Various eating and body size-related factors and psychosomatic symptoms were significantly associated with high body dissatisfaction and drive for thinness in both genders. In women, early puberty onset, early initiation of sexual activity, and multiple sex partners were statistically significant risk factors of body dissatisfaction. In gender-specific univariate twin models, additive genes accounted for 59.4% (95% confidence interval [CI] = 53.2-64.7%) of the variance in body dissatisfaction and for 51.0% (95% CI = 43.7-57.5%) of the variance in drive for thinness among females, but for none of the variance among males.

DISCUSSION

There are very distinct gender differences in the heritability patterns of body dissatisfaction and drive for thinness in young adults.

Reliability of self-reported eating disorders: Optimizing population screening

OBJECTIVE

The objective of this study was to assess whether short self-report eating disorder screening questions are useful population screening methods.

METHOD

We screened the female participants (N = 2881) from the 1975-1079 birth cohorts of Finnish twins for eating disorders, using several short screening questions and three Eating Disorder Inventory (EDI) subscales. Comparing these measures with clinician-conducted semi-structured diagnostic interviews (N = 549) of Diagnostic and Statistical Manual of Mental Disorders-IV (DSM-IV) anorexia and bulimia, we calculated their sensitivities and specificities and drew receiver operating characteristic curves to further compare these items.

RESULTS

For current and lifetime bulimia, best tradeoffs between sensitivity and specificity were reached by addressing purging behaviors. For current and lifetime anorexia, the questions "Have you ever had anorexia" and "Has anybody ever suspected that you might have an eating disorder?" optimized tradeoffs between sensitivity and specificity. These questions generally outperformed EDI subscales.

CONCLUSION

Simple screening questions, although less than ideal, are at least as good as other available instruments for community screenings.

Epidemiology of binge eating disorder: prevalence, course, comorbidity, and risk factors

PURPOSE OF REVIEW

Binge eating disorder (BED) is a new diagnosis in the Fifth Edition of the Diagnostic and Statistic Manual of Mental Disorders (DSM-5) and the Eleventh Revision of the International Classification of Diseases (ICD-11).

RECENT FINDINGS

DSM-5 BED is currently estimated to affect 1.5% of women and 0.3% of men worldwide; a lifetime diagnosis of DSM-5 BED is reported by 0.6-1.8% of women and 0.3-0.7% of men. In adolescence, BED is even more prevalent, but often transient. Many adults with BED report longstanding symptoms; less than half are recognized in healthcare. Commonly co-occurring conditions include obesity, type 2 diabetes, and hypertension. In a nationally representative US-based study, up to 23% of individuals with BED had attempted suicide, and virtually all (94%) reported lifetime mental health symptoms: 70% mood disorders, 68% substance use disorders, 59% anxiety disorders, 49% borderline personality disorder, and 32% posttraumatic stress disorder. Data on mortality are scarce, but the standardized mortality ratio of BED is estimated to be 1.5-1.8. Various minority statuses, deprivation, violence, trauma, and major mental illness may increase the risk of BED.

SUMMARY

BED is often invisible and overlooked, perhaps due to societal biases. For this reason, prevention, detection, and management of BED are closely linked with social justice and equity.

Epidemiology of anorexia nervosa in men: a nationwide study of Finnish twins

Background

To examine the epidemiology of anorexia nervosa in men, we screened Finnish male twins born in 1975–79.

Methods and Findings

Men (N = 2122) from FinnTwin16 birth cohorts were screened for lifetime eating disorders by a questionnaire. The screen positives (N = 18), their male co-twins (N = 10) and those with lifetime minimum BMI≤17.5 (N = 21) were administered the Structured Clinical Interview for DSM-IV anorexia nervosa. The incidence rate of anorexia nervosa for the presumed peak age of risk (10–24y) was 15.7 per 100 000 person-years; its lifetime prevalence was 0.24%. All probands had recovered from eating disorders, but suffered from substantial psychiatric comorbidity, which also manifested in their co-twins. Additionally, male co-twins displayed significant dissatisfaction with body musculature, a male-specific feature of body dysmorphic disorder.

Conclusions

Anorexia nervosa in males in the community is more common, transient and accompanied by more substantial comorbidity than previously thought.

Brain serotonin 1A receptor binding in bulimia nervosa

BACKGROUND

Selective serotonin reuptake inhibitors (SSRIs) are the first choice for the pharmacologic treatment of bulimia nervosa, but there are no published data on the putative altered serotonin (5-HT) receptor characteristics in patients with bulimia. Experimental studies suggest that the therapeutic antidepressant effect of SSRIs is mediated via 5-HT(1A) receptors. The aim of this study was to measure brain 5-HT(1A) receptor binding among nonmedicated patients with bulimia nervosa.

METHODS

Positron emission tomography (PET) with a selective 5-HT(1A) ligand, [11C]WAY-100635, was performed on eight unmedicated patients with bulimia and 10 healthy comparison subjects.

RESULTS

The binding potential values were greater in patients than in control subjects in all brain regions studied. The most robust differences were observed in the angular gyrus, the medial prefrontal cortex, and the posterior cingulate cortex.

CONCLUSIONS

These results suggest that brain 5-HT(1A) receptor binding is increased in several cortical areas in patients with bulimia nervosa during their state of impulsive binge eating.

Are computer and cell phone use associated with body mass index and overweight? A population study among twin adolescents

Background

Overweight in children and adolescents has reached dimensions of a global epidemic during recent years. Simultaneously, information and communication technology use has rapidly increased.

Methods

A population-based sample of Finnish twins born in 1983–1987 (N = 4098) was assessed by self-report questionnaires at 17 y during 2000–2005. The association of overweight (defined by Cole's BMI-for-age cut-offs) with computer and cell phone use and ownership was analyzed by logistic regression and their association with BMI by linear regression models. The effect of twinship was taken into account by correcting for clustered sampling of families. All models were adjusted for gender, physical exercise, and parents' education and occupational class.

Results

The proportion of adolescents who did not have a computer at home decreased from 18% to 8% from 2000 to 2005. Compared to them, having a home computer (without an Internet connection) was associated with a higher risk of overweight (odds ratio 2.3, 95% CI 1.4 to 3.8) and BMI (beta coefficient 0.57, 95% CI 0.15 to 0.98). However, having a computer with an Internet connection was not associated with weight status. Belonging to the highest quintile (OR 1.8 95% CI 1.2 to 2.8) and second-highest quintile (OR 1.6 95% CI 1.1 to 2.4) of weekly computer use was positively associated with overweight. The proportion of adolescents without a personal cell phone decreased from 12% to 1% across 2000 to 2005. There was a positive linear trend of increasing monthly phone bill with BMI (beta 0.18, 95% CI 0.06 to 0.30), but the association of a cell phone bill with overweight was very weak.

Conclusion

Time spent using a home computer was associated with an increased risk of overweight. Cell phone use correlated weakly with BMI. Increasing use of information and communication technology may be related to the obesity epidemic among adolescents.

Prevalence and correlates of binge eating disorder related features in the community

Binge eating disorder (BED) is associated with high levels of obesity and psychological suffering, but little is known about 1) the distribution of features of BED in the general population and 2) their consequences for weight development and psychological distress in young adulthood. We investigated the prevalence of features of BED and their association with body mass index (BMI) and psychological distress among men (n = 2423) and women (n = 2825) from the longitudinal community-based FinnTwin16 cohort (born 1975-1979). Seven eating-related cognitions and behaviors similar to the defining features of BED were extracted from the Eating Disorder Inventory-2 and were assessed at a mean age of 24. BMI and psychological distress, measured with the General Health Questionnaire, were assessed at ages 24 and 34. We assessed prevalence of the features and their association with BMI and psychological distress cross-sectionally and prospectively. More than half of our participants reported at least one feature of BED; clustering of several features in one individual was less common, particularly among men. The most frequently reported feature was 'stuffing oneself with food', whereas the least common was 'eating or drinking in secrecy'. All individual features of BED and their clustering particularly were associated with higher BMI and more psychological distress cross-sectionally. Prospectively, the clustering of features of BED predicted increase in psychological distress but not additional weight gain when baseline BMI was accounted for. In summary, although some features of BED were common, the clustering of several features in one individual was not. The features were cumulatively associated with BMI and psychological distress and predicted further increase in psychological distress over ten years of follow-up.

Factors associated with recovery from anorexia nervosa: a population-based study

BACKGROUND

To examine factors associated with the outcome of anorexia nervosa among women from the general population.

METHOD

Women (N = 2,881) from the 1975-1979 birth cohorts of Finnish twins were screened for lifetime DSM-IV anorexia nervosa (N = 55 cases) using questionnaires and the SCID interview. Potential factors associated with the likelihood of recovery were addressed in the same assessment. Recovery was defined as restoration of weight, menstruation, and the absence of bingeing and purging for at least one year prior to assessment. Using two-tailed t tests and Pearson's chi-square tests, we contrasted recovered (N = 39) and unrecovered (N = 16) women. We then used logistic regression adjusted for duration of illness and Cox proportional hazard models to account for the variable lengths of illness on prognostic factors.

RESULTS

Unrecovered women were more likely to suffer from depressive symptoms prior to eating disorder onset (18.8% vs. 2.6%, p = 0.04), remain unemployed (18.8% vs. 2.6%, p = 0.04), report dissatisfaction with their current partner/spouse (p = 0.02), and report high perfectionism (p = 0.05) than were recovered women. When duration of illness was accounted for in the analyses, premorbid depression was the sole factor significantly associated with decreased likelihood of recovery (hazard ratio 0.17, 95% confidence interval: 0.03-0.89).

DISCUSSION

Predicting the course of anorexia remains fraught with difficulty, but premorbid depressive symptoms are associated with poor outcome of anorexia nervosa in the general population.

Genome-wide association analysis of eating disorder-related symptoms, behaviors, and personality traits

Eating disorders (EDs) are common, complex psychiatric disorders thought to be caused by both genetic and environmental factors. They share many symptoms, behaviors, and personality traits, which may have overlapping heritability. The aim of the present study is to perform a genome-wide association scan (GWAS) of six ED phenotypes comprising three symptom traits from the Eating Disorders Inventory 2 [Drive for Thinness (DT), Body Dissatisfaction (BD), and Bulimia], Weight Fluctuation symptom, Breakfast Skipping behavior and Childhood Obsessive-Compulsive Personality Disorder trait (CHIRP). Investigated traits were derived from standardized self-report questionnaires completed by the TwinsUK population-based cohort. We tested 283,744 directly typed SNPs across six phenotypes of interest in the TwinsUK discovery dataset and followed-up signals from various strata using a two-stage replication strategy in two independent cohorts of European ancestry. We meta-analyzed a total of 2,698 individuals for DT, 2,680 for BD, 2,789 (821 cases/1,968 controls) for Bulimia, 1,360 (633 cases/727 controls) for Childhood Obsessive-Compulsive Personality Disorder trait, 2,773 (761 cases/2,012 controls) for Breakfast Skipping, and 2,967 (798 cases/2,169 controls) for Weight Fluctuation symptom. In this GWAS analysis of six ED-related phenotypes, we detected association of eight genetic variants with P < 10(-5) . Genetic variants that showed suggestive evidence of association were previously associated with several psychiatric disorders and ED-related phenotypes. Our study indicates that larger-scale collaborative studies will be needed to achieve the necessary power to detect loci underlying ED-related traits.

Eating styles, overweight and obesity in young adult twins

OBJECTIVE

To explore the association of eating styles with overweight and obesity in young adults, controlling for identical genetic background in monozygotic twins.

DESIGN

Prospective twin cohort study.

SETTING

Finland, 1991-2002.

SUBJECTS

Two-hundred and thirty-three women and 2060 men from the FinnTwin16 study, aged 16 years at baseline (T1), and ranging from 22 to 27 years at the time of the nutritional assessment (T4).

METHODS

Eating styles (Restrictive/overeating, health-conscious, snacking, emotional and externally induced), self-reported at T4, were contrasted with body mass indices (BMIs) at T1 and T4.

RESULTS

At T4, obesity (BMI>or=30Kg/m(2)) was significantly cross-sectionally associated with restrictive eating, frequent snacks, eating in the evening, avoiding fatty foods and failure to maintain healthy eating patterns. These associations were independent of BMI at T1. Obese women self-reported more vulnerability to external eating cues and comfort eating than normal-weight women. However, in a multivariable model, only restrictive/overeating and health-conscious eating styles were significant correlates of obesity at T4, independent of gender and BMI at T1. When we controlled for genetic background restricting the analysis to the 39 female and 45 male monozygotic twin pairs discordant for obesity or overweight (BMI>or=25Kg/m(2)), restrictive/overeating eating style was still statistically significantly associated with excess weight.

CONCLUSIONS

The eating styles of obese young adults differ from their normal-weight counterparts: restrictive eating, overeating and fewer healthy food choices are associated with obesity. Different eating styles may partially explain weight differences in individuals with identical genetic background.

Minor depression in adolescence: phenomenology and clinical correlates

BACKGROUND

Depressions that fail to meet the diagnostic criteria for major depressive disorder (MDD) may be underdiagnosed and undertreated in adolescent population. Traditionally, they are not considered as serious conditions and the phenomenological nature and clinical correlates of these disorders are largely unknown. In the present study, we used a large, representative and age-standardized sample of adolescents to examine the phenomenology and clinical correlates of minor depression, a poorly understood condition included in the category of Depressive Disorder Not Otherwise Specified in Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition-Text Revised (DSM-IV-TR).

METHODS

909 girls and 945 boys, with mean age of 14, were interviewed by professionals using the Semi-Structured Assessment for the Genetics of Alcoholism (SSAGA).

RESULTS

Although clearly milder condition than MDD, minor depression was associated with marked suicidal thoughts, plans and attempts, recurrences and a high degree of comorbidity. At this early age, despite that 14% of adolescents under 15 had suffered from depressive conditions with severe clinical implications, most of them failing to meet the diagnostic threshold for MDD, only 1.7% had received any psychiatric treatment. 40% of depressive adolescents who had attempted suicide had no contact with mental health services.

LIMITATIONS

Analyzed in a cross-sectional setting, no conclusions about long-term implications could be made.

CONCLUSIONS

The results highlight the clinical and public health significance of non-MDD depressions, e.g. minor depression, which need to be more carefully identified and treated at early age.

Genetic and environmental factors affecting self-esteem from age 14 to 17: a longitudinal study of Finnish twins

BACKGROUND

We analysed genetic and environmental influences on self-esteem and its stability in adolescence.

METHOD

Finnish twins born in 1983-1987 were assessed by questionnaire at ages 14 (n = 4132 twin individuals) and 17 years (n = 3841 twin individuals). Self-esteem was measured using the Rosenberg global self-esteem scale and analyzed using quantitative genetic methods for twin data in the Mx statistical package.

RESULTS

The heritability of self-esteem was 0.62 [95% confidence interval (CI) 0.56-0.68] in 14-year-old boys and 0.40 (95% CI 0.26-0.54) in 14-year-old girls, while the corresponding estimates at age 17 were 0.48 (95% CI 0.39-0.56) and 0.29 (95% CI 0.11-0.45). Rosenberg self-esteem scores at ages 14 and 17 were modestly correlated (r = 0.44 in boys, r = 0.46 in girls). In boys, the correlation was mainly (82%) due to genetic factors, with residual co-variation due to unique environment. In girls, genetic (31%) and common environmental (61%) factors largely explained the correlation.

CONCLUSIONS

In adolescence, self-esteem seems to be differently regulated in boys versus girls. A key challenge for future research is to identify environmental influences contributing to self-esteem during adolescence and determine how these factors interact with genetic influences.