An investigation of indirect effects of personality features on anorexia nervosa severity through interoceptive dysfunction in individuals with lifetime anorexia nervosa diagnoses

OBJECTIVE

This study examined a hypothesized pathway by which interoceptive dysfunction accounted for associations between personality features (harm avoidance, self-directedness, and perfectionism) and anorexia nervosa (AN) severity (indicated by drive for thinness, eating disorder-related preoccupations and rituals, and body mass index).

METHOD

The study sample (n = 270, mean age = 28.47, 95.2% female, 98% White/Caucasian) consisted of probands and biological relatives who met DSM-IV criteria for lifetime diagnoses of AN (omitting criterion D, amenorrhea) drawn from the Price Foundation Anorexia Nervosa Affected Relative Pairs Study (AN-ARP). Participants completed measures assessing personality, interoceptive dysfunction, and eating pathology.

RESULTS

Associations between personality features of low self-directedness and high perfectionism and indicators of AN severity (drive for thinness and eating disorder-related preoccupations and rituals) were significant, as were the hypothesized indirect pathways through interoceptive dysfunction. Neither harm avoidance nor body mass index was significantly related to other study variables, and the proposed indirect pathways involving these variables were not significant.

DISCUSSION

Findings suggest that certain personality features may relate to AN severity, in part, through their associations with interoceptive dysfunction. Future research should examine prospective associations and the value of interventions targeting interoceptive dysfunction for interrupting the link between personality and AN severity.

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 [h²_SNP]), partitioned heritability, and genetic correlations (r_g) 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 h²_SNP 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.

Computerized measurement of anticipated anxiety from eating increasing portions of food in adolescents with and without anorexia nervosa: Pilot studies

Dieting and excessive fear of eating coexist in vulnerable individuals, which may progress to anorexia nervosa [AN], but there is no objective measure of this fear. Therefore, we adapted a computer program that was previously developed to measure the satiating effects of foods in order to explore the potential of food to induce anxiety and fear of eating in adolescent girls. Twenty four adolescents (AN) and ten healthy controls without eating disorders rated pictures of different types of foods in varying sized portions as too large or too small and rated the expected anxiety of five different portions (20-320 kcal). Two low energy dense (potatoes and rice) and two high energy dense (pizza and M&Ms) foods were used. The regression coefficient of line lengths (0-100 mm) marked from "No anxiety" to "this would give me a panic attack", regressed from portions shown, was the measure of "expected anxiety" for a given food. The maximum tolerated portion size [kcal] (MTPS), computed by method of constant stimulus from portions shown, was significantly smaller for high energy dense foods, whereas the expected anxiety response was greater, for all foods, for patients compared to controls. For both groups, expected anxiety responses were steeper, and maximum tolerated portion sizes were larger, for low, than high, energy dense foods. Both maximum tolerated portion size and expected anxiety response were significantly predicted by severity of illness for the patients. Those who had larger maximum tolerated portion sizes had smaller anticipated anxiety to increasing portion sizes. Visual size had a greater influence than energy content for these responses. This method could be used to quantify the anxiety inducing potential of foods and for studies with neuro-imaging and phenotypic clarifications.

Larger hippocampus size in women with anorexia nervosa who exercise excessively than healthy women

Exercise has been shown to increase hippocampal volume in healthy older adults. Observations from animal models of diabetes and hypertension suggest that the combination of exercise and caloric restriction may exert greater neuroprotection in the hippocampus than either behavior alone. Yet, in humans, the effects of exercise and caloric restriction on the hippocampus are not known. We measured the volume of the hippocampus prior to clinical treatment in women with anorexia nervosa (AN) who were restricting calories and engaging in excessive exercise, women with AN who did not exercise excessively, and healthy women who did not engage in either behavior. Women with AN were also examined longitudinally (once weight was restored and 6 months later). In the present report, we found that women with AN engaged in caloric restriction and excessive exercising prior to clinical treatment had larger hippocampal volumes than healthy comparison women. After weight restoration, women with AN who had engaged in food restriction and excessive exercise prior to treatment had hippocampal volumes similar to that of women with AN who only engaged in caloric restriction. These results advance the field by showing for the first time that hippocampal volume may be increased by exercise alone or exercise interacting with food restriction in AN.

Challenges in conducting a multi-site randomized clinical trial comparing treatments for adolescent anorexia nervosa

OBJECTIVE

To describe obstacles in the implementation of a controlled treatment trial of adolescent anorexia nervosa (AN).

METHOD

The original aim was to enter 240 participants with AN to one of four cells: Behavioral family therapy (BFT) plus fluoxetine; BFT plus placebo; systems family therapy (SFT) plus fluoxetine; SFT plus placebo.

RESULTS

Recruitment was delayed pending a satisfactory resolution concerning participant safety. After 6 months of recruitment it became clear that the medication was associated with poor recruitment leading to a study redesign resulting in a comparison of two types of family therapy with a projected sample size of 160. One site was unable to recruit and was replaced.

DISCUSSION

Problems with the delineation of safety procedures, recruitment, re-design of the study, and replacement of a site, were the main elements resulting in a 1-year delay. Suggestions are made for overcoming such problems in future AN trials.

Stepped care and cognitive-behavioural therapy for bulimia nervosa: randomised trial

BACKGROUND

This study compared the best available treatment for bulimia nervosa, cognitive-behavioural therapy (CBT) augmented by fluoxetine if indicated, with a stepped-care treatment approach in order to enhance treatment effectiveness.

AIMS

To establish the relative effectiveness of these two approaches.

METHOD

This was a randomised trial conducted at four clinical centres (Clinicaltrials.gov registration number: NCT00733525). A total of 293 participants with bulimia nervosa were randomised to one of two treatment conditions: manual-based CBT delivered in an individual therapy format involving 20 sessions over 18 weeks and participants who were predicted to be non-responders after 6 sessions of CBT had fluoxetine added to treatment; or a stepped-care approach that began with supervised self-help, with the addition of fluoxetine in participants who were predicted to be non-responders after six sessions, followed by CBT for those who failed to achieve abstinence with self-help and medication management.

RESULTS

Both in the intent-to-treat and completer samples, there were no differences between the two treatment conditions in inducing recovery (no binge eating or purging behaviours for 28 days) or remission (no longer meeting DSM-IV criteria). At the end of 1-year follow-up, the stepped-care condition was significantly superior to CBT.

CONCLUSIONS

Therapist-assisted self-help was an effective first-level treatment in the stepped-care sequence, and the full sequence was more effective than CBT suggesting that treatment is enhanced with a more individualised approach.

The genetics of anorexia nervosa collaborative study: methods and sample description

OBJECTIVE

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).

METHOD

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.

RESULTS

We report attributes of the first 200 families, comprising 200 probands and 232 affected relatives.

CONCLUSION

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.

Eating disorder symptoms in pregnancy: a prospective study

OBJECTIVE

Previous work suggests that eating disorder symptoms diminish with pregnancy. However, little prospective study has been conducted, and little is known about pregnancy symptoms in eating disorder not otherwise specified. This research prospectively studies both eating behaviors and disordered eating cognitions in pregnant women with various eating disorder diagnoses.

METHOD

Forty-two participants became pregnant during 4-year follow-up of 385 women with full or subthreshold anorexia nervosa, bulimia nervosa, or binge eating disorder. Participants completed the Eating Disorders Examination (EDE) at 6-month intervals. Mixed modeling procedures were used to examine change in eating disorder cognitions, binge eating, and purging.

RESULTS

EDE restraint, EDE shape concerns, EDE weight concerns, binge eating, and purging diminished from prepartum to intrapartum, but returned to approximately baseline levels postpartum.

CONCLUSION

In this longitudinal sample of women with diverse eating disorder diagnoses, eating disorder symptoms improved during pregnancy, but worsened postpartum. These results highlight pregnancy as a potential time for eating disorder interventions.

A trial of a relapse prevention strategy in women with bulimia nervosa who respond to cognitive-behavior therapy

OBJECTIVE

This study examines a relapse prevention strategy for bulimia nervosa (BN). Subjects in a multicenter BN treatment trial who initially achieved abstinence after a course of cognitive-behavioral therapy (CBT) were told to recontact the clinic if they had a recurrence of symptoms or feared such a reoccurrence so that they could receive additional therapy visits.

METHOD

At the end of CBT, subjects whose scores on the Eating Disorders Examination indicated that they were abstinent from binge eating and purging, and therefore considered to be treated successfully, were assigned randomly to follow-up only or to a crisis intervention model. With the crisis intervention model, subjects would receive additional visits if needed.

RESULTS

None of the 30 subjects who relapsed during the follow-up sought additional treatment visits.

DISCUSSION

Simply telling patients with BN who appear to have been successfully treated to come back if they have additional problems, or fear that they are developing such problems, may be an ineffective relapse prevention technique. Alternative strategies, such as planned return visits or phone calls, should be considered as alternative relapse prevention strategies.

Participant recruitment for an anorexia nervosa treatment study

OBJECTIVE

To investigate the nature of differing recruitment rates for clinical treatment trials for anorexia nervosa and bulimia nervosa.

METHODS

Recruitment rates from a study recruiting women partially recovered from anorexia nervosa were compared with the rates from two studies conducted at the same sites recruiting women with bulimia nervosa.

RESULTS

At all sites in the anorexia study, the total number of contacts per month rose steadily over the first 2 years of the recruitment phase then decreased to near zero with the number of participants randomized to the study practically evaporating. In contrast, the bulimia studies screened a larger group of contacts and met monthly randomization goals in the time allotted for recruitment. Participants eligible for a study but with a barrier to participation occurred at a much higher rate in the anorexia study than in the bulimia studies.

DISCUSSION

These results reveal a difficulty in planning recruitment from a small population such as partially recovered anorexics. A small population's total pool size diminishes faster than it is replenished, suggesting that future studies of anorexia nervosa may recruit more successfully from many sites in a short period rather than at a few sites over a long period.

Candidate genes for anorexia nervosa in the 1p33-36 linkage region: serotonin 1D and delta opioid receptor loci exhibit significant association to anorexia nervosa

Serotonergic and opioidergic neurotransmitter system alterations have been observed in people with eating disorders; the genes for the serotonin 1D receptor (HTR1D) and the opioid delta receptor (OPRD1) are found on chr1p36.3-34.3, a region identified by our group in a linkage analysis of anorexia nervosa (AN). These candidate genes were evaluated for sequence variation and for linkage and association of this sequence variation to AN in family and case : control data sets. Resequencing of the HTR1D locus and a portion of the OPRD1 locus identified novel SNPs and confirmed existing SNPs. Genotype assay development and genotyping of nine SNPs (four at HTR1D and five at OPRD1) was performed on 191 unrelated individuals fulfilling DSM-IV criteria (w/o amenorrhea criterion) for AN, 442 relatives of AN probands and 98 psychiatrically screened controls. Linkage analysis of these candidate gene SNPs with 33 microsatellite markers in families including relative pairs concordantly affected with restricting AN (N=37) substantially increased the evidence for linkage of this region to restricting AN to an NPL score of 3.91. Statistically significant genotypic, allelic, and haplotypic association to AN in the case : control design was observed at HTR1D and OPRD1 with effect sizes for individual SNPs of 2.63 (95% CI=1.21-5.75) for HTR1D and 1.61 (95% CI=1.11-2.44) for OPRD1. Using genotype data on parents and AN probands, three SNPs at HTR1D were found to exhibit significant transmission disequilibrium (P&<0.05). The combined statistical genetic evidence suggests that HTR1D and OPRD1 or linked genes may be involved in the etiology of AN.

Full syndromal versus subthreshold anorexia nervosa, bulimia nervosa, and binge eating disorder: a multicenter study

OBJECTIVE

The diagnostic criteria for anorexia nervosa (AN), bulimia nervosa (BN), and binge eating disorder (BED) establish symptom severity levels, which are used to separate full cases from partial cases. However, the value of these distinctions is unclear.

METHOD

Three hundred eighty-five women with full or partial AN, BN, or BED were assessed at entry into a longitudinal study of eating disorders.

RESULTS

Stepwise discriminant analysis revealed that full and partial BN were discriminated by the Yale-Brown-Cornell Eating Disorders Scale total scores (kappa =.46). However, it was not possible to discriminate between full and partial AN or BED. Discriminant analysis also demonstrated clear differences between full AN, BN, and BED.

DISCUSSION

Full BN can be differentiated from partial BN by more severe eating disorder symptoms, whereas both full and partial AN and full and partial BED appear quite similar. These results emphasize the distinct nature of AN, BN, and BED, as well as the similarities between full and partial cases.

A randomized secondary treatment study of women with bulimia nervosa who fail to respond to CBT

OBJECTIVE

Since the description of bulimia nervosa as a distinct diagnostic entity in 1979, several psychological and pharmacological interventions have been developed and empirically tested. The existence of several effective treatments, none of which is completely effective, is common to most psychiatric conditions. The research question that flows from such findings is whether second-level treatments would be effective for those who fail initial treatment.

METHOD

In the case of bulimia nervosa, the research findings suggest that cognitive behavioral therapy (CBT) is the first level of treatment and that both antidepressant medication and interpersonal psychotherapy (IPT) may potentially be effective second-level treatments. This was a multicenter study in which 194 patients were initially treated with CBT. Those treated unsuccessfully (n = 62) were then randomized to treatment with IPT or medication management.

RESULTS

Of those assigned to secondary treatment, 37 completed such treatment and 25 dropped out or were withdrawn. The abstinence rate for subjects assigned to treatment with IPT was 16% and for those assigned to medication management was 10%. No significant differences were found between medication and IPT in either the intent-to-treat or completer analysis.

DISCUSSION

Dropout rates were high, and response rates were low among BN patients assigned to secondary treatments who failed to achieve remission with CBT. Offering lengthy sequential treatments appears to have little value, and alternative models for therapy need to be tested.

Establishing guidelines for pharmacotherapy trials in bulimia nervosa and anorexia nervosa

OBJECTIVE

This paper addresses the lack of a standard protocol for pharmacotherapy trials for patients with bulimia nervosa (BN) and anorexia nervosa (AN).

METHOD

Twenty-two surveys were sent to established researchers in the field of eating disorders to elicit their opinions regarding medication trials, including baseline laboratory tests, the optimal length/frequency of medication management sessions, and the information that should or should not be included in these sessions.

RESULTS

Sixteen of 22 researchers completed and returned the survey. Their answers are the basis of the data presented.

DISCUSSION

We propose a battery of screening laboratory tests for both conditions. We suggest 30-45-min initial medication management sessions in both AN and BN trials with 15-min follow-ups to be held weekly for AN subjects, and weekly for 2 weeks, then biweekly for 2 weeks, then monthly, for BN subjects. We also recommend that published trials should include explicit details of medication management.

Psychopharmacology in the treatment of anorexia nervosa and bulimia nervosa

Anorexia nervosa and bulimia nervosa remain enigmatic disorders with poorly understood etiologies. Clinicians continue to find these disorders very challenging to treat. As their underlying pathophysiology is clarified, it is hoped that specific pharmacologic treatments will be developed to alleviate the pain and disability these disorders produce.

DSM-III-R personality disorders in patients with eating disorders

The authors conducted a systematic examination of DSM-III-R personality disorders among 35 patients with eating disorders. Fifty-seven percent of the patients met the criteria for at least one axis II diagnosis; borderline, self-defeating, and avoidant were the most frequently assigned personality disorders. Forty percent of the patients were given two or more diagnoses, and 17% of the patients met criteria for five to seven diagnoses. No differences were found between patients with anorexia nervosa, anorexia and bulimia nervosa, and bulimia nervosa in the distribution of diagnoses or the frequency with which individual criteria (traits) were assigned.

Monozygotic twins concordant and discordant for anorexia nervosa

The occurrence of anorexia nervosa in monozygotic twins discordant and concordant for this illness is reviewed. Two additional pairs of identical twins, one discordant and the other concordant for anorexia nervosa, are described.