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 2,907 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 datasets. Seventy-six (72 independent) SNPs were taken forward for in silico (two datasets) or de novo (13 datasets) replication genotyping in 2,677 independent AN cases and 8,629 European ancestry controls along with 458 AN cases and 421 controls from Japan. The final global meta-analysis across discovery and replication datasets comprised 5,551 AN cases and 21,080 controls. AN subtype analyses (1,606 AN restricting; 1,445 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 to 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 that 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.
anorexia nervosa; eating disorders; GWAS; genome-wide association study; body mass index; metabolic
We examined prevalence of substance use disorders (SUD) in women with: (1) anorexia nervosa (AN) restricting type (RAN); (2) AN with purging only (PAN); (3) AN with binge eating only (BAN); and (4) lifetime AN and bulimia nervosa (ANBN). Secondary analyses examined SUD related to lifetime purging behavior and lifetime binge eating.
Participants (N = 731) were drawn from the International Price Foundation Genetic Studies.
The prevalence of SUD differed across AN subtypes, with more in the ANBN group reporting SUD than those in the RAN and PAN groups. Individuals who purged were more likely to report substance use than those who did not purge. Prevalence of SUD differed across lifetime binge eating status.
SUD are common in AN and are associated with bulimic symptomatology. Results underscore the heterogeneity in AN, highlighting the importance of screening for SUD across AN subtypes.
eating disorders; anorexia nervosa; bulimia nervosa; drug use; alcohol related disorders; cannabis
Anorexia nervosa (AN) is a highly heritable young-onset psychiatric illness the etiology of which remains unknown. Estrogen alpha and beta receptors, encoded by ESR1 and ESR2 genes, are involved in food intake regulation and eating behavior, and may have a potential role in AN. We performed a family-based association study of 17 single-nucleotide polymorphisms (SNPs) encompassing ESR1 and ESR2 genes in a cohort of 321 French AN families. We attempted to replicate this finding in a cohort of 41 restrictive AN (RAN) families and in a population-based study of 693 young women. Using the transmission disequilibrium test, a significant over-transmission was detected between AN and ESR1 rs726281 and rs2295193. These SNPs and another among ESR1 were more specifically associated with the RAN subtype (rs726281, p=0.005, odds ratio (OR)=2.1, 95% confidence interval (95% CI)=1.2–3.6; rs3798577, p=0.021, OR=1.6, 95% CI=1.1–2.3; and rs2295193, p=0.007, OR=1.7, 95% CI=1.2–2.5). A large eight-SNPs haplotype of ESR1 gene was also associated with AN (p<0.0001, OR=3.1, 95% CI=1.8–5.1). Association of ESR1 SNPs and RAN was driven by paternal over-transmissions (p<0.0001, OR=3.7, 95% CI=1.9–7.3). Furthermore, we confirmed the preferential paternal over-transmission of the ESR1 rs726281 on the independent German sample of 41 RAN trios (p=0.025, OR=3, 95% CI=1.1–8.3). Finally, rs3798577 was associated with eating disorders in a population-based sample of 693 women (p<0.01). Our findings are strongly in favor of an association between ESR1 polymorphisms and AN. In particular, ESR1 gene confers a high risk of vulnerability to the restrictive subtype of AN, and suggests that the estrogen pathway has to be further analyzed in AN.
anorexia nervosa; restrictive type; binge-eating/purging type; estrogen receptors; transmission disequilibrium test; population-based sample; Eating / Metabolic Disorders; Neurogenetics; Biological Psychiatry; Molecular & Cellular Neurobiology; Anorexia nervosa; estrogen receptors; restrictive type; binge-eating / purging type; transmission disequilibrium test; population-based sample
Individuals who suffer from Anorexia Nervosa refuse to maintain a minimally normal body weight, are intensely afraid of gaining weight and exhibit a significant disturbance in the perception of the shape and size of their body. Postmenarchal females with this disorder are amenorrohic. In the Binge-Eating/Purging subtype individuals regularly engage in binge eating and purging behaviour (i.e self-induced vomiting or misuse of laxatives, diuretics, or enemas).
Hypokalaemia is often seen in chronic Anorexia Nervosa, especially that of the purging type (ANp), and, as well as electrocardiographic anomalies, this can lead to tubulointerstitial nephritis (hypokalaemic nephropathy) with typical histological characteristics. The physiopathological mechanisms behind this damage are linked to altered stimulation of vasoactive mediators, and to the ammonium-mediated activation of the alternative complement pathway. However, it has not yet been ascertained whether a variant of the pathway specific for ANp , exists.
We describe herein a case of hypokalaemic nephropathy in a patient affected by chronic ANp who presented to our Centre for Eating Disorders.
Hypokalaemia can provoke cardiovascular alterations as well as muscular and renal complications, and thus potential renal damage needs to be investigated in patients suffering from long-term purgative anorexia.
To further refine our understanding of impulsivity, obsessions, and compulsions in anorexia nervosa (AN) by isolating which behaviors—binge eating, purging, or both—are associated with these features.
We conducted regression analyses with binge eating, purging, and the interaction of binge eating with purging as individual predictors of scores for impulsivity, obsessions, and compulsions in two samples of women with AN (n = 1373).
Purging, but not binge eating, was associated with higher scores of impulsivity, obsessions and compulsions. Purging was also associated with worst eating rituals and with worst eating preoccupations.
Our results suggest that purging, compared with binge eating, may be a stronger correlate of impulsivity, obsessions, and compulsions in AN.
anorexia nervosa; impulsivity; compulsivity; binge eating; purging
This case report details the therapeutic effects of tandospirone on two patients with anorexia nervosa, one with the restricting subtype (ANR), and another with the binge-eating/purging subtype (ANBP). A 22-year-old female patient with ANR and a 23-year-old female patient with ANBP were treated successfully with the 5-HT1A partial agonist tandospirone. After treatment, not only did both patients gain weight, they also showed improved scores on the Eating Disorder Examination Questionnaire. In addition, a 6-month follow-up showed maintenance of these effects. In this disorder, tandospirone may be an effective drug for long-term use with good patient compliance.
Anorexia nervosa; Pharmacotherapy; Treatment; Serotonin 1A receptor; Tandospirone
Elucidation of clinically relevant subtypes has been proposed as a means of advancing treatment research, but classifying anorexia nervosa (AN) patients into restricting and binge-eating/purging types has demonstrated limited predictive validity. This study aimed to evaluate whether an approach to classifying eating disorder patients based on comorbid personality psychopathology has utility in predicting treatment response and readmission in patients with AN.
Data were collected from 154 AN patients (M[SD] age = 25.6[9.4] years; 95.5% female; 96.8% Caucasian) at admission, discharge, and three months post-discharge from intensive treatment. Latent profile analysis of personality traits assessed at admission was performed to classify participants into personality subtypes, which were then used to predict outcomes at discharge and risk of readmission.
The best-fitting model identified three personality subtypes (undercontrolled, overcontrolled, low psychopathology) that contributed significantly to multivariate models predicting study outcomes. Undercontrolled patients were more likely to have a poor outcome at discharge than overcontrolled (OR = 3.56, p = .01) and low psychopathology patients (OR = 11.23, p <.001). Undercontrolled patients also had a greater risk of discharge against medical advice (HR = 2.08, p = .02) and readmission than overcontrolled patients (HR = 3.76, p = .009). Binge-eating/purging versus restricting subtypes did not predict discharge against medical advice or readmission in the multivariate models.
Findings support the clinical utility of personality subtypes in AN. Future work is needed to identify mechanisms that explain diminished treatment response in undercontrolled patients and to develop interventions for this high-risk group.
anorexia nervosa; subtypes; personality; latent profile analysis; treatment
Patients with anorexia nervosa-restricting type (AN-R) sometimes develop accompanying bulimic symptoms or the full syndrome of bulimia nervosa (BN). If clinicians could predict who might change into the bulimic sub-type or BN, preventative steps could be taken. Therefore, we investigated anthropometric and psychological factors possibly associated with such changes.
All participants were from a study by the Japanese Genetic Research Group for Eating Disorders. Of 80 patients initially diagnosed with AN-R, 22 changed to the AN-Binge Eating/Purging Type (AN-BP) and 14 to BN for some period of time. The remaining 44 patients remained AN-R only from the onset to the investigation period. Variables compared by ANOVA included anthropometric measures, personality traits such as Multiple Perfectionism Scale scores and Temperament and Character Inventory scores, and Beck Depression Inventory-II scores.
In comparison with AN-R only patients, those who developed BN had significantly higher current BMI (p < 0.05) and maximum BMI in the past (p < 0.05). They also scored significantly higher for the psychological characteristic of parental criticism (p < 0.05) and lower in self-directedness (p < 0.05), which confirms previous reports, but these differences disappeared when the depression score was used as a co-variant. No significant differences were obtained for personality traits or depression among the AN-R only patients irrespective of their duration of illness.
The present findings suggest a tendency toward obesity among patients who cross over from AN-R to BN. Low self-directedness and high parental criticism may be associated with the development of BN by patients with AN-R, although the differences may also be associated with depression.
Supported by National Institute of Mental Health (NIMH), this 12-site international collaboration seeks to identify genetic variants that affect risk for anorexia nervosa (AN).
Four hundred families will be ascertained with two or more individuals affected with AN. The assessment battery produces a rich set of phenotypes comprising eating disorder diagnoses and psychological and personality features known to be associated with vulnerability to eating disorders.
We report attributes of the first 200 families, comprising 200 probands and 232 affected relatives.
These results provide context for the genotyping of the first 200 families by the Center for Inherited Disease Research. We will analyze our first 200 families for linkage, complete recruitment of roughly 400 families, and then perform final linkage analyses on the complete cohort. DNA, genotypes, and phenotypes will form a national eating disorder repository maintained by NIMH and available to qualified investigators.
anorexia nervosa; eating disorders; bulimia nervosa; psychiatric disorders; genetics; linkage analysis; genomics
Anorexia nervosa is regarded a s a typical culture bound syndrome, and its existence is negligible in nonwestern countries due to protective biological and socio-cultural factors. Most of the cases reported from nonwestern countries are atypical in presentation with lack of body image disturbances. Recent studies showed that anorexia nervosa is no more culture bound, in fact it is a "culture change syndrome" due to westernization and no differences are seen in the phenomenology of anorexia nervosa between the two cultures. We report a typical case of anorexia nervosa of binge eating and purging type associated with body dysmorphophobia in an adolescent girl.
Anorexia Nervosa; Culture bound syndrome; binge eating
Eating disorders such as anorexia (AN) and bulimia nervosa (BN) are characterized by abnormal eating behavior. The essential aspect of AN is that the individual refuses to maintain a minimal normal body weight. The main features of BN are binge eating and inappropriate compensatory methods to prevent weight gain. The gut-brain-adipose tissue (AT) peptides and neutralizing autoantibodies play an important role in the regulation of eating behavior and growth hormone release. The mechanisms for controlling food intake involve an interplay between gut, brain, and AT. Parasympathetic, sympathetic, and serotoninergic systems are required for communication between brain satiety centre, gut, and AT. These neuronal circuits include neuropeptides ghrelin, neuropeptide Y (NPY), peptide YY (PYY), cholecystokinin (CCK), leptin, putative anorexigen obestatin, monoamines dopamine, norepinephrine (NE), serotonin, and neutralizing autoantibodies. This extensive and detailed report reviews data that demonstrate that hunger-satiety signals play an important role in the pathogenesis of eating disorders. Neuroendocrine dysregulations of the AT-gut-brain axis peptides and neutralizing autoantibodies may result in AN and BN. The circulating autoantibodies can be purified and used as pharmacological tools in AN and BN. Further research is required to investigate the orexigenic/anorexigenic synthetic analogs and monoclonal antibodies for potential treatment of eating disorders in clinical practice.
Fibroblast growth factor (FGF) 23, a circulating 26-kDa peptide produced by osteogenic cells, is a novel phosphaturic factor. In our previous study, binge-eating/purging type anorexia nervosa (AN-BP) patients had elevated plasma intact FGF23 (iFGF23) levels, while restricting type (AN-R) patients had plasma iFGF23 levels similar to healthy controls. Although bulimia nervosa (BN) patients as well as some patients with AN-BP regularly engage in binge eating, there have been no studies regarding plasma iFGF23 levels in BN patients. Therefore, this study was performed to determine plasma iFGF23 concentrations in BN patients and healthy controls. The study population consisted of 13 female BN patients and 11 healthy female controls. Blood samples were collected from all subjects after overnight fasting. Plasma iFGF23 was measured using an ELISA kit in a cross-sectional manner. The two-tailed Mann-Whitney U-test was used to assess differences between BN patients and healthy controls. In addition, BN patients were divided into two groups based on questionnaire-reported binge eating frequency immediately prior to participation in this study: high frequency of binge eating (once a week or more; HF group; n = 8) and low frequency of binge eating (less than once a week; LF group; n = 5). Two-tailed Mann-Whitney U-test with Bonferroni's correction was performed after the Kruskal-Wallis test to assess differences between HF group, LF group, and healthy controls. Median (quartiles) plasma iFGF23 levels were greater in BN patients (35.5 [14.8-65.0] pg/ml) than in controls (3.8 [not detected-5.3] pg/ml; p = 0.002). In addition, median (quartiles) plasma iFGF23 levels were greater in the HF group (62.3 [44.4-73.4] pg/ml) than in controls (p < 0.001) and in the LF group (12.9 [not detected-30.3] pg/ml; p = 0.011), while there were no differences between the LF group and controls (p = 0.441). This is the first study to show that BN patients have elevated plasma iFGF23 levels. Moreover, this study showed that BN patients with a high frequency of binge eating have elevated plasma iFGF23 levels, while iFGF23 levels are similar to healthy controls in those with a low frequency of binge eating. Plasma iFGF23 level may be a suitable indicator of binge eating in BN patients.
fibroblast growth factor 23 (FGF23); intact fibroblast growth factor 23 (iFGF23); eating disorders; bulimia nervosa (BN); binge eating; frequency of binge eating; dietary phosphate; plasma phosphate; 1,25-dihydroxyvitamin D (1,25-(OH)2D)
Acute gastric dilatation is a rare complication of anorexia nervosa binge/purge subtype that results from gastrointestinal abnormalities, including decreased gastric motility and delayed gastric emptying. Early diagnosis and intervention is critical since delay may result in gastric necrosis, perforation, shock, and death. We report a 26-year-old female with anorexia nervosa binge/purge subtype, who presented with abdominal pain and nausea after a binge episode. Abdominal radiography and computed tomography showed a grossly dilated stomach measuring 32 cm × 17.9 cm consistent with acute gastric dilatation. She underwent exploratory laparotomy with gastrotomy and gastric decompression, and recovered uneventfully. Initially, the patient denied the binge episode, as many patients with eating disorders do, but later revealed an extensive history of anorexia nervosa binge/purge subtype. This case stresses the importance of obtaining a thorough history of eating disorders and maintaining a high index of suspicion for acute gastric dilatation in young women who present with abdominal pain and distention.
Acute gastric dilatation; anorexia; binge/purge; denial; eating disorder; gastric dysmotility
In spite of the role of some psychosomatic factors as alexithymia, mood intolerance, and somatization in both pathogenesis and maintenance of anorexia nervosa (AN), few studies have investigated the prevalence of psychosomatic syndromes in AN. The aim of this study was to use the Diagnostic Criteria for Psychosomatic Research (DCPR) to assess psychosomatic syndromes in AN and to evaluate if psychosomatic syndromes could identify subgroups of AN patients.
108 AN inpatients (76 AN restricting subtype, AN-R, and 32 AN binge-purging subtype, AN-BP) were consecutively recruited and psychosomatic syndromes were diagnosed with the Structured Interview for DCPR. Participants were asked to complete psychometric tests: Body Shape Questionnaire, Beck Depression Inventory, Eating Disorder Inventory–2, and Temperament and Character Inventory. Data were submitted to cluster analysis.
Illness denial (63%) and alexithymia (54.6%) resulted to be the most common syndromes in our sample. Cluster analysis identified three groups: moderate psychosomatic group (49%), somatization group (26%), and severe psychosomatic group (25%). The first group was mainly represented by AN-R patients reporting often only illness denial and alexithymia as DCPR syndromes. The second group showed more severe eating and depressive symptomatology and frequently DCPR syndromes of the somatization cluster. Thanatophobia DCPR syndrome was also represented in this group. The third group reported longer duration of illness and DCPR syndromes were highly represented; in particular, all patients were found to show the alexithymia DCPR syndrome.
These results highlight the need of a deep assessment of psychosomatic syndromes in AN. Psychosomatic syndromes correlated differently with both severity of eating symptomatology and duration of illness: therefore, DCPR could be effective to achieve tailored treatments.
Anorexia nervosa; Eating disorders; Psychosomatic syndromes; Illness denial; Alexithymia
Comorbidity among eating disorders, traumatic events, and post traumatic stress disorder (PTSD) has been reported in several studies. The main objectives of this study were to describe the nature of traumatic events experienced and to explore the relation between PTSD and anorexia nervosa (AN) in a sample of women.
Eight hundred twenty-four participants from the National Institutes of Health funded Genetics of Anorexia Nervosa Collaborative Study were assessed for eating disorders, PTSD, and personality characteristics.
From a final sample of 753 women with AN, 13.7% (n=103) met DSM-IV criteria for PTSD. The sample mean age was 29.5 years (SD=11.1). In pairwise comparisons across AN subtypes, the odds of having a PTSD diagnosis were significantly lower in individuals with restricting AN (RAN) than individuals with purging AN without binge eating (PAN) (OR=0.49, 95% CI=0.30, 0.80). The majority of participants with PTSD reported the first traumatic event before the onset of AN (64.1%, n=66). The most common traumatic events reported by those with a PTSD diagnosis were sexual related traumas during childhood (40.8%) and during adulthood (35.0%).
AN and PTSD do co-occur and traumatic events tend to occur prior to the onset of AN. Clinically, these results underscore the importance of assessing trauma history and PTSD in individuals with AN and raise the question of whether specific modifications or augmentations to standard treatment for AN should be considered in a subgroup to address PTSD-related psychopathology.
PTSD; anorexia nervosa; trauma; prevalence; comorbid; epigenetic
The purpose of this paper is to review the available literature that addresses the predictive validity and utility of subtyping anorexia nervosa patients into binge/purge and restrictor subtypes.
Literature was reviewed including studies that compared individuals with subtype diagnoses on clinical and outcome variables as well as more recent research examining the frequency of diagnostic crossover.
Several studies found that in general the binge/purge subtype patients have more psychopathology, tend to be older and tend to have a worse outcome. More recent studies which have examined diagnostic crossover suggest that the rate of crossover from the restrictor subtype to the binge/purge subtype is substantial. Crossover from the binge/purge to the restrictor subtype appears to occur less commonly. There is also literature documenting crossover from anorexia nervosa to bulimia nervosa and a small literature looking at crossover from bulimia nervosa to anorexia nervosa.
The results of this review suggest that although there is generally progression from restrictor anorexia nervosa to binge/purge anorexia nervosa to bulimia nervosa in a sizeable number of patients, other crossover patterns can be seen as well, and the amount of crossover is quite large. This suggests a lack of predictive validity for subtypes. Validity and Utility of Subtyping Anorexia Nervosa
The current study tested a psychosocial interactive model of perfectionism, self-efficacy, and weight/shape concern within a sample of women with clinically significant bulimic symptoms, examining how different dimensions of perfectionism operated in the model. Individuals with bulimia nervosa (full diagnostic criteria or subthreshold) completed measures of bulimic symptoms, multidimensional perfectionism, self-efficacy, and weight/shape concern. Among those who were actively binge eating (n = 180), weight/shape concern was associated with binge eating frequency in the context of high perfectionism (either maladaptive or adaptive) and low self-efficacy. Among those who were actively vomiting (n = 169), weight/shape concern was associated with vomiting frequency only in the context of high adaptive perfectionism and low self-efficacy. These findings provide support for the value of this psychosocial interactive model among actively binge eating and purging samples and for the importance of considering different dimensions of perfectionism in research and treatment related to bulimia nervosa.
Perfectionism; Self-efficacy; Body dissatisfaction; Binge eating; Vomiting
The aim of our study was to determine the central and peripheral autonomic nervous system profiles underlying anorexia nervosa (AN) syndrome, given that affected patients present with the opposite clinical profile to that seen in the hyperinsulinism syndrome.
We measured blood pressure and heart rate, as well as circulating neurotransmitters (noradrenaline, adrenaline, dopamine, plasma serotonin, and platelet serotonin), using high-performance liquid chromatography with electrochemical detection, during supine resting, one minute of orthostasis, and after five minutes of exercise. In total, 22 AN patients (12 binge-eating/purging type and 10 restricting type) and age-, gender-, and race-matched controls (70 ± 10.1% versus 98 ± 3.0% of ideal body weight) were recruited.
We found that patients with AN had adrenal sympathetic overactivity and neural sympathetic underactivity, demonstrated by a predominance of circulating adrenaline over noradrenaline levels, not only during the supine resting state (52 ± 2 versus 29 ± 1 pg/mL) but also during orthostasis (67 ± 3 versus 32 ± 2 pg/mL, P < 0.05) and after exercise challenge (84 ± 4 versus 30 ± 3 pg/mL, P < 0.01).
Considering that this peripheral autonomic nervous system disorder depends on the absolute predominance of adrenomedullary C1 adrenergic nuclei over A5 noradrenergic pontine nucleus, let us ratify the abovementioned findings. The AN syndrome depends on the predominance of overwhelming adrenal sympathetic activity over neural sympathetic activity. This combined central and autonomic nervous system profile contrasts with that registered in patients affected by hyperinsulinism, hypoglycemia, and bulimia syndrome which depends on the absolute predominance of neural sympathetic activity.
anorexia nervosa; adrenal sympathetic activity; adrenaline; noradrenaline; eating disorders
Fibroblast growth factor (FGF)23 is a novel phosphaturic factor associated with inorganic phosphate homeostasis. Previous human studies have shown that serum FGF23 levels increase in response to a high phosphate diet. For anorexia nervosa (AN) patients, inorganic phosphate homeostasis is important in the clinical course, such as in refeeding syndrome. The purpose of this study was to determine plasma levels of intact FGF23 (iFGF23) in restricting-type AN (AN-R) patients, binge-eating/purging-type AN (AN-BP) patients, and healthy controls.
The subjects consisted of 6 female AN-R patients, 6 female AN-BP patients, and 11 healthy female controls; both inpatients and outpatients were included. Plasma iFGF23, 1,25-dihydroxyvitamin D (1,25-(OH)2D), and 25-hydroxyvitamin D (25-OHD) levels were measured. Data are presented as the median and the range. A two-tailed Mann-Whitney U-test with Bonferroni correction was used to assess differences among the three groups, and a value of p < 0.017 was considered statistically significant.
There were no differences between AN-R patients and controls in the iFGF23 and 1,25-(OH)2D levels. In AN-BP patients, the iFGF23 level (41.3 pg/ml; range, 6.1–155.5 pg/ml) was significantly higher than in controls (3.8 pg/ml; range, not detected-21.3 pg/ml; p = 0.001), and the 1,25-(OH)2D was significantly lower in AN-BP patients (7.0 pg/ml; range, 4.2–33.7 pg/ml) than in controls (39.7 pg/ml; range, 6.3–58.5 pg/ml; p = 0.015). No differences in plasma 25-OHD levels were observed among the groups.
This preliminary study is the first to show that plasma iFGF23 levels are increased in AN-BP patients, and that these elevated plasma FGF23 levels might be related to the decrease in plasma 1,25-(OH)2D levels.
Food intake is mediated, in part, through brain pathways for motivation and reinforcement. Dysregulation of these pathways may underlay some of the behaviors exhibited by patients with eating disorders. Research using animal models of eating disorders has greatly contributed to the detailed study of potential brain mechanisms that many underlie the causes or consequences of aberrant eating behaviors. This review focuses on neurochemical evidence of reward-related brain dysfunctions obtained through animal models of binge eating, bulimia nervosa, or anorexia nervosa. The findings suggest that alterations in dopamine (DA), acetylcholine (ACh) and opioid systems in reward-related brain areas occur in response to binge eating of palatable foods. Moreover, animal models of bulimia nervosa suggest that while bingeing on palatable food releases DA, purging attenuates the release of ACh that might otherwise signal satiety. Animal models of anorexia nervosa suggest that restricted access to food enhances the reinforcing effects of DA when the animal does eat. The activity-based anorexia model suggests alterations in mesolimbic DA and serotonin occur as a result of starvation coupled with excessive wheel running. These findings with animal models complement data obtained through neuroimaging and pharmacotherapy studies of clinical populations. Finally, information on the neurochemical consequences of the behaviors associated with these eating disorders will be useful in understanding these complex disorders and may inform future therapeutic approaches, as discussed here.
acetylcholine; binge eating; clinical studies; dopamine; eating disorders; opioids; rat; serotonin
Extensive population-based genome-wide association studies have identified an association between the FTO gene and BMI; however, the mechanism of action is still unknown. To determine whether FTO may influence weight regulation through psychological and behavioral factors, seven single nucleotide polymorphisms (SNPs) of the FTO gene were genotyped in 1085 individuals with anorexia nervosa (AN) and 677 healthy weight controls from the international Price Foundation Genetic Studies of Eating Disorders. Each SNP was tested in association with eating disorder phenotypes and measures that have previously been associated with eating behavior pathology: trait anxiety, harm-avoidance, novelty seeking, impulsivity, obsessionality, compulsivity, and concern over mistakes. After appropriate correction for multiple comparisons, no significant associations between individual FTO gene SNPs and eating disorder phenotypes or related eating behavior pathology were identified in cases or controls. Thus, this study found no evidence that FTO gene variants associated with weight regulation in the general population are associated with eating disorder phenotypes in AN participants or matched controls.
Pharmacotherapy for anorexia nervosa is considered to be of limited efficacy. However, many studies suffer methodological limitations, and the utility of newer drugs in the treatment of anorexia has not been examined yet. Although there have been more fruitful investigations on the efficacy of medication in the management of bulimia nervosa, there are still many unresolved issues regarding the optimal management of partial remission during the acute treatment phase and the intensity and duration of pharmacotherapy to achieve optimal prophylaxis. Selective serotonin reuptake inhibitors (SSRIs) control the binge urges in binge-eating disorder, but more trials are required to investigate the utility of SSRIs and other agents in maintenance treatment. We review the current status of psychopharmacotherapy for anorexia nervosa, bulimia nervosa and binge-eating disorder and evaluate the merits of newer agents in the treatment of these disorders.
Several lines of evidence indicate that the central cannabinoid receptor 1 (CNR1) as well as the major endocannabinoid degrading enzymes fatty acid amide hydrolase (FAAH), N-acylethanolamine-hydrolyzing acid amidase (NAAA) and monoglyceride lipase (MGLL) are implicated in mediating the orexigenic effects of cannabinoids. The aim of this study was to analyse whether nucleotide sequence variations in the CNR1, FAAH, NAAA and MGLL genes are associated with anorexia nervosa (AN).
We analysed the association of a previously described (AAT)n repeat in the 3' flanking region of CNR1 as well as a total of 15 single nucleotide polymorphisms (SNPs) representative of regions with restricted haplotype diversity in CNR1, FAAH, NAAA or MGLL in up to 91 German AN trios (patient with AN and both biological parents) using the transmission-disequilibrium-test (TDT). One SNP was additionally analysed in an independent case-control study comprising 113 patients with AN and 178 normal weight controls. Genotyping was performed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, ARMS-PCR or using 3730xl capillary sequencers.
The TDT revealed no evidence for association for any of the SNPs or the (AAT)n repeat with AN (all two-sided uncorrected p-values > 0.05). The lowest p-value of 0.11 was detected for the A-allele of the CNR1 SNP rs1049353 for which the transmission rate was 59% (95% confidence interval 47%...70%). Further genotyping of rs1049353 in 113 additional independent patients with AN and 178 normal weight controls could not substantiate the initial trend for association (p = 1.00).
As we found no evidence for an association of genetic variation in CNR1, FAAH, NAAA and MGLL with AN, we conclude that genetic variations in these genes do not play a major role in the etiology of AN in our study groups.
This analysis is a follow-up to an earlier investigation of 182 genes selected as likely candidate genetic variations conferring susceptibility to anorexia nervosa (AN). As those initial case-control results revealed no statistically significant differences in single nucleotide polymorphisms, herein we investigate alternative phenotypes associated with AN. In 1762 females using regression analyses we examined: (1) lowest illness-related attained body mass index; (2) age at menarche; (3) drive for thinness; (4) body dissatisfaction; (5) trait anxiety; (6) concern over mistakes; and (7) the anticipatory worry and pessimism vs. uninhibited optimism subscale of the harm avoidance scale. After controlling for multiple comparisons, no statistically significant results emerged. Although results must be viewed in the context of limitations of statistical power, the approach illustrates a means of potentially identifying genetic variants conferring susceptibility to AN because less complex phenotypes associated with AN are more proximal to the genotype and may be influenced by fewer genes.
covariates; eating disorders; association studies; personality; genetic
Anorexia nervosa (AN) and bulimia nervosa (BN) are marked by longitudinal symptom fluctuations. DSM-IV-TR does not address how to classify eating disorder (ED) presentations in individuals who no longer meet full criteria for these disorders. To consider this issue, we examined subthreshold presentations in women with initial diagnoses of AN and BN.
A total of 246 women with AN or BN were followed for a median of 9 years; weekly symptom data were collected at frequent intervals using the Longitudinal Interval Follow-up Evaluation of Eating Disorders (LIFE-EAT-II). Outcomes were ED presentations that were subthreshold for ≥3 months, including those narrowly missing full criteria for AN or BN, along with binge eating disorder (BED) and purging disorder.
During follow-up, most women (77.6%) experienced a subthreshold presentation. Subthreshold presentation was related to intake diagnosis (Wald χ2 = 8.065, df = 2, p = 0.018). Individuals with AN most often developed subthreshold presentations resembling AN; those with BN were more likely to develop subthreshold BN. Purging disorder was experienced by half of those with BN and one-quarter of those with AN binge/purge type (ANBP); BED occurred in 20% with BN. Transition from AN or BN to most subthreshold types was associated with improved psychosocial functioning (p < 0.001).
Subthreshold presentations in women with lifetime AN and BN were common, resembled the initial diagnosis, and were associated with modest improvements in psychosocial functioning. For most with lifetime AN and BN, subthreshold presentations seem to represent part of the course of illness and to fit within the original AN or BN diagnosis.
Anorexia nervosa; bulimia nervosa; classification; eating disorder not otherwise specified; longitudinal