Anorexia nervosa and generalized anxiety disorder: further explorations of the relation between anxiety and body mass index

Anxiety and restrained eating in everyday life: An ecological momentary assessment study

BACKGROUND

Restrained eating has been related to psychological distress like anxiety and eating disorder symptomatology, but little is known about this relationship in daily life in non-clinical populations. We aimed to understand concurrent and temporal associations between momentary anxiety and restrained eating in everyday life within and across persons in a non-clinical sample, and examined whether this association remains after controlling for eating disorder symptomatology.

METHODS

We used a 10-day ecological momentary assessment (EMA) protocol. Participants (n = 123) completed a baseline survey with demographics and eating disorder symptomatology questions, and three EMA surveys per day reporting anxiety and restrained eating intentions. We applied mixed-effects and random intercept cross-lagged models to analyze the data.

RESULTS

Momentary anxiety and restrained eating were concurrently significantly positively associated within and between persons. When participants had more anxiety than was typical for them, they were more likely to intend to restrain eating, and people with overall higher anxiety symptoms tended to report greater restrained eating over the study period. These associations remained significant after adjusting for eating disorder symptomatology. There were no significant temporal cross-lagged effects. Anxiety-restrained eating association did not spill over into the next assessment window.

LIMITATIONS

The time window between prompts may have been too long to capture potential temporal effects, and we did not examine actual behavioral food restrictions.

CONCLUSION

Daily-life anxiety may be related to concurrent restrained eating intentions, above and beyond baseline eating disorder symptomatology. Research is needed exploring daily-life anxiety as a potential intervention target to address restrained eating.

Does Relative Energy Deficiency in Sport (REDs) Syndrome Exist?

Relative energy deficiency in sport (REDs) is a widely adopted model, originally proposed by an International Olympic Committee (IOC) expert panel in 2014 and recently updated in an IOC 2023 consensus statement. The model describes how low energy availability (LEA) causes a wide range of deleterious health and performance outcomes in athletes. With increasing frequency, sports practitioners are diagnosing athletes with "REDs," or "REDs syndrome," based largely upon symptom presentation. The purpose of this review is not to "debunk" REDs but to challenge dogmas and encourage rigorous scientific processes. We critically discuss the REDs concept and existing empirical evidence available to support the model. The consensus (IOC 2023) is that energy availability, which is at the core of REDs syndrome, is impossible to measure accurately enough in the field, and therefore, the only way to diagnose an athlete with REDs appears to be by studying symptom presentation and risk factors. However, the symptoms are rather generic, and the causes likely multifactorial. Here we discuss that (1) it is very difficult to isolate the effects of LEA from other potential causes of the same symptoms (in the laboratory but even more so in the field); (2) the model is grounded in the idea that one factor causes symptoms rather than a combination of factors adding up to the etiology. For example, the model does not allow for high allostatic load (psychophysiological "wear and tear") to explain the symptoms; (3) the REDs diagnosis is by definition biased because one is trying to prove that the correct diagnosis is REDs, by excluding other potential causes (referred to as differential diagnosis, although a differential diagnosis is supposed to find the cause, not demonstrate that it is a pre-determined cause); (4) observational/cross-sectional studies have typically been short duration (< 7 days) and do not address the long term "problematic LEA," as described in the IOC 2023 consensus statement; and (5) the evidence is not as convincing as it is sometimes believed to be (i.e., many practitioners believe REDs is well established). Very few studies can demonstrate causality between LEA and symptoms, most studies demonstrate associations and there is a worrying number of (narrative) reviews on the topic, relative to original research. Here we suggest that the athlete is best served by an unbiased approach that places health at the center, leaving open all possible explanations for the presented symptoms. Practitioners could use a checklist that addresses eight categories of potential causes and involve the relevant experts if and when needed. The Athlete Health and Readiness Checklist (AHaRC) we introduce here simply consists of tools that have already been developed by various expert/consensus statements to monitor and troubleshoot aspects of athlete health and performance issues. Isolating the purported effects of LEA from the myriad of other potential causes of REDs symptoms is experimentally challenging. This renders the REDs model somewhat immune to falsification and we may never definitively answer the question, "does REDs syndrome exist?" From a practical point of view, it is not necessary to isolate LEA as a cause because all potential areas of health and performance improvement should be identified and tackled.

Taking better advantage of the activity-based anorexia model

The lack of specific treatments for anorexia nervosa (AN) is partly driven by an inadequate understanding of the neurobiological drivers of the condition. The activity-based anorexia (ABA) model recapitulates key characteristics of AN in rats and mice, and can be used to understand factors that predispose, maintain, and rescue anorectic behaviour. With the rapidly evolving suite of technologies to manipulate and record neural activity during the development of ABA, we are better placed than ever before to take advantage of this unique biobehavioural model in order to develop and refine novel treatments for AN. This will require a collective effort to bridge research disciplines in order to capitalise on knowledge gains from genetics, neurobiology, metabolism, and cognition.

Examining anxious temperament in anorexia nervosa: Behavioural inhibition and intolerance of uncertainty and their contribution to trait anxiety in adolescents with anorexia nervosa

BACKGROUND

Anorexia nervosa (AN) is a serious and complex psychiatric disorder yet treatment results are suboptimal. Insight into the etiology of this illness is much needed. Research highlights the implication of anxiety-related traits in the development and maintenance of AN. This study investigates firstly, behavioural inhibition and intolerance for uncertainty (IU) in adolescents with and without AN, and secondly relations between these traits.

METHODS

In a cross-sectional study, 165 adolescent girls (AN = 94, HC = 71) completed questionnaires measuring behavioural inhibition, IU and trait anxiety. ANOVAs tested differences between AN and HC groups, and mediation models with IU as a mediator between behavioural inhibition and trait anxiety were run.

RESULTS

AN adolescents reported significantly higher levels of behavioural inhibition, IU and trait anxiety compared to their peers. In both AN and HC, a direct and a total effect of behavioural inhibition on trait anxiety was found. However, only in the AN group IU partially mediated the relation between behavioural inhibition and trait anxiety.

LIMITATIONS

Data is cross-sectional and longitudinal studies are required. A mean illness duration of nearly 2 years may mean early effects of malnourishment and habituation and future studies should include patients with shorter illness duration.

CONCLUSIONS

Results highlight that behavioural inhibition and IU may contribute to anxiety in AN whilst their peers may have developed better executive and social-emotional skills to manage uncertainty. Adolescents with AN may benefit from interventions targeting behavioural inhibition and IU.

An excitatory projection from the basal forebrain to the ventral tegmental area that underlies anorexia-like phenotypes

Maladaptation in balancing internal energy needs and external threat cues may result in eating disorders. However, brain mechanisms underlying such maladaptations remain elusive. Here, we identified that the basal forebrain (BF) sends glutamatergic projections to glutamatergic neurons in the ventral tegmental area (VTA) in mice. Glutamatergic neurons in both regions displayed correlated responses to various stressors. Notably, in vivo manipulation of BF terminals in the VTA revealed that the glutamatergic BF → VTA circuit reduces appetite, increases locomotion, and elicits avoidance. Consistently, activation of VTA glutamatergic neurons reduced body weight, blunted food motivation, and caused hyperactivity with behavioral signs of anxiety, all hallmarks of typical anorexia symptoms. Importantly, activation of BF glutamatergic terminals in the VTA reduced dopamine release in the nucleus accumbens. Collectively, our results point to overactivation of the glutamatergic BF → VTA circuit as a potential cause of anorexia-like phenotypes involving reduced dopamine release.

Latent anxiety and depression dimensions differ amongst patients with eating disorders: A Swedish nationwide investigation

OBJECTIVE

Anxiety and depression symptoms are common in individuals with eating disorders. To study these co-occurrences, we need high-quality self-report questionnaires. The 19-item self-rated Comprehensive Psychopathological Rating Scale for Affective Syndromes (CPRS-S-A) is not validated in patients with eating disorders. We tested its factor structure, invariance, and differences in its latent dimensions.

METHOD

Patients were registered by 45 treatment units in the Swedish nationwide Stepwise quality assurance database for specialised eating disorder care (n = 9509). Patients self-reported their anxiety and depression symptoms on the CPRS-S-A. Analyses included exploratory and confirmatory factor analyses (CFA) in split samples, and testing of invariance and differences in subscales across eating disorder types.

RESULTS

Results suggested a four-factor solution: Depression, Somatic and fear symptoms, Disinterest, and Worry. Multigroup CFA indicated an invariant factor structure. We detected the following differences: Patients with anorexia nervosa binge-eating/purging subtype scored the highest and patients with unspecified feeding and eating disorders the lowest on all subscales. Patients with anorexia nervosa or purging disorder show more somatic and fear symptoms than individuals with either bulimia nervosa or binge-eating disorder.

CONCLUSION

Our four-factor solution of the CPRS-S-A is suitable for patients with eating disorders and may help to identify differences in anxiety and depression dimensions amongst patients with eating disorders.

Risk factors for eating disorders: findings from a rapid review

BACKGROUND

Risk factors represent a range of complex variables associated with the onset, development, and course of eating disorders. Understanding these risk factors is vital for the refinement of aetiological models, which may inform the development of targeted, evidence-based prevention, early intervention, and treatment programs. This Rapid Review aimed to identify and summarise research studies conducted within the last 12 years, focusing on risk factors associated with eating disorders.

METHODS

The current review forms part of a series of Rapid Reviews to be published in a special issue in the Journal of Eating Disorders, funded by the Australian Government to inform the development of the National Eating Disorder Research and Translation Strategy 2021-2031. Three databases were searched for studies published between 2009 and 2021, published in English, and comprising high-level evidence studies (meta-analyses, systematic reviews, moderately sized randomised controlled studies, moderately sized controlled-cohort studies, or population studies). Data pertaining to risk factors for eating disorders were synthesised and outlined in the current paper.

RESULTS

A total of 284 studies were included. The findings were divided into nine main categories: (1) genetics, (2) gastrointestinal microbiota and autoimmune reactions, (3) childhood and early adolescent exposures, (4) personality traits and comorbid mental health conditions, (5) gender, (6) socio-economic status, (7) ethnic minority, (8) body image and social influence, and (9) elite sports. A substantial amount of research exists supporting the role of inherited genetic risk in the development of eating disorders, with biological risk factors, such as the role of gut microbiota in dysregulation of appetite, an area of emerging evidence. Abuse, trauma and childhood obesity are strongly linked to eating disorders, however less conclusive evidence exists regarding developmental factors such as role of in-utero exposure to hormones. Comorbidities between eating disorders and mental health disorders, including personality and mood disorders, have been found to increase the severity of eating disorder symptomatology. Higher education attainment, body image-related factors, and use of appearance-focused social media are also associated with increased risk of eating disorder symptoms.

CONCLUSION

Eating disorders are associated with multiple risk factors. An extensive amount of research has been conducted in the field; however, further studies are required to assess the causal nature of the risk factors identified in the current review. This will assist in understanding the sequelae of eating disorder development and in turn allow for enhancement of existing interventions and ultimately improved outcomes for individuals.

The Roles of Anxiety and Self-Esteem in the Risk of Eating Disorders and Compulsive Buying Behavior

In contemporary society, following the sudden changes that occur, different forms of addiction are becoming popular. Of note are the new addictions and concepts of poly-dependencies that involve common behaviors and trap people who suffering from them in a vicious circle. The main goal of this study is to investigate the possible mediating role that self-esteem had between trait anxiety and two specific new addictions: compulsive buying behavior and eating disorders. Furthermore, it was verified through a multigroup analysis that trait anxiety had a greater effect on eating disorders in a group of compulsive consumers. Three-hundred and fifty-two participants (67.9% women) were enrolled to participate in this study. The results showed that there was a direct effect of trait anxiety on eating disorders and on compulsive buying behavior; self-esteem mediated the effect of trait anxiety on eating disorders and compulsive buying behavior with specific differences; multi-group analysis showed differences in anxiety's effect on eating disorders between compulsive and non-compulsive consumers; the group of compulsive consumers revealed a significant and stronger effect of trait anxiety on eating disorders in all domains identified. Further research is recommended to better understand the predictors of these disorders and to contribute to a more effective preventive intervention.

Psychiatric and medical comorbidities of eating disorders: findings from a rapid review of the literature

BACKGROUND

Eating disorders (EDs) are potentially severe, complex, and life-threatening illnesses. The mortality rate of EDs is significantly elevated compared to other psychiatric conditions, primarily due to medical complications and suicide. The current rapid review aimed to summarise the literature and identify gaps in knowledge relating to any psychiatric and medical comorbidities of eating disorders.

METHODS

This paper forms part of a rapid review) series scoping the evidence base for the field of EDs, conducted to inform the Australian National Eating Disorders Research and Translation Strategy 2021-2031, funded and released by the Australian Government. ScienceDirect, PubMed and Ovid/Medline were searched for English-language studies focused on the psychiatric and medical comorbidities of EDs, published between 2009 and 2021. High-level evidence such as meta-analyses, large population studies and Randomised Control Trials were prioritised.

RESULTS

A total of 202 studies were included in this review, with 58% pertaining to psychiatric comorbidities and 42% to medical comorbidities. For EDs in general, the most prevalent psychiatric comorbidities were anxiety (up to 62%), mood (up to 54%) and substance use and post-traumatic stress disorders (similar comorbidity rates up to 27%). The review also noted associations between specific EDs and non-suicidal self-injury, personality disorders, and neurodevelopmental disorders. EDs were complicated by medical comorbidities across the neuroendocrine, skeletal, nutritional, gastrointestinal, dental, and reproductive systems. Medical comorbidities can precede, occur alongside or emerge as a complication of the ED.

CONCLUSIONS

This review provides a thorough overview of the comorbid psychiatric and medical conditions co-occurring with EDs. High psychiatric and medical comorbidity rates were observed in people with EDs, with comorbidities contributing to increased ED symptom severity, maintenance of some ED behaviours, and poorer functioning as well as treatment outcomes. Early identification and management of psychiatric and medical comorbidities in people with an ED may improve response to treatment and overall outcomes.

In pursuit of biomarkers for predicting susceptibility to activity-based anorexia in adolescent female rats

OBJECTIVE

Identifying risk factors that contribute to the development of anorexia nervosa (AN) is critical for the implementation of early intervention strategies. Anxiety, obsessive-compulsive behavior, and immune dysfunction may be involved in the development of AN; however, their direct influence on susceptibility to the condition remains unclear. Here, we used the activity-based anorexia (ABA) model to examine whether activity, anxiety-like behavior, compulsive behavior, and circulating immune markers predict the subsequent development of pathological weight loss.

METHOD

Female Sprague-Dawley rats (n = 44) underwent behavioral testing before exposure to ABA conditions after which they were separated into susceptible and resistant subpopulations. Blood was sampled before behavioral testing and after recovery from ABA to screen for proinflammatory cytokines.

RESULTS

Rats that were vulnerable to pathological weight loss differed significantly from resistant rats on all key ABA parameters. While the primary measures of anxiety-like or compulsive behavior were not shown to predict vulnerability to ABA, increased locomotion and anxiety-like behavior were both associated with the extent of weight loss in susceptible but not resistant animals. Moreover, the change in expression of proinflammatory markers IL-4 and IL-6 evoked by ABA was associated with discrete vulnerability factors. Intriguingly, behavior related to risk assessment was shown to predict vulnerability to ABA.

DISCUSSION

We did not find undisputable behavioral or immune predictors of susceptibility to pathological weight loss in the ABA rat model. Future research should examine the role of cognition in the development of ABA, dysfunction of which may represent an endophenotype linking anorectic, anxiety-like and compulsive behavior.

PUBLIC SIGNIFICANCE

Anorexia nervosa (AN) has among the highest mortality rates of all psychiatric disorders and treatment options remain limited in their efficacy. Understanding what types of risk factors contribute to the development of AN is essential for implementing early intervention strategies. This study describes how some of the most common psychological features of AN could be used to predict susceptibility to pathological weight loss in a well-established animal model.

Fear and food: Anxiety-like behavior and the susceptibility to weight loss in an activity-based anorexia rat model

Anorexia nervosa (AN) is a severe psychiatric disorder characterized by energy restriction, low body weight, a fear of gaining weight, and often excessive physical activity. Anxiety disorders appear to constitute a major risk factor for developing AN and are the most frequent comorbidity. Here, the influence of anxiety-like behavior prior to food restriction on increased physical activity, leading to greater susceptibility to weight loss, was tested in rats. Furthermore, the possible anxiolytic effect of starvation itself was analyzed. A chronic starvation model activity-based anorexia (ABA) was applied to mimic physiological and behavioral characteristics of AN. During the induction of starvation and acute starvation, food intake was reduced by 70% and the rats lost 25% of their body weight, which was kept stable to imitate chronic starvation. Anxiety-like behavior was quantified before and after chronic starvation using the elevated plus maze, based on rodents' aversion to open spaces. Anxiety-related behavior before food restriction was associated with increased running-wheel activity during habituation and during the induction of starvation, and predicted faster weight loss in ABA rats. Additionally, food-restricted animals showed less anxiety-like behavior after chronic starvation. Animals showing more anxiety-like behavior appear to be more susceptible to weight loss, partially mediated by increased physical activity. Anxiety-related behavior was associated with increased physical activity, which in turn was associated with more rapid weight loss. Our data let us assume that food restriction has an anxiolytic effect. These findings demonstrate the importance of considering anxiety disorders in patients with AN.

High levels of physical activity in female adolescents with anorexia nervosa: medical and psychopathological correlates

PURPOSE

While overexercise is commonly described in patients who experience anorexia nervosa (AN), it represents a condition still underestimated, especially in the paediatric population.

METHOD

The present study aims at assessing the possible associations between levels of physical activity (PA) and clinical features, endocrinological data and psychopathological traits in a sample of 244 female adolescents hospitalised for AN subdivided into two groups according to PA levels (high PA vs. no/low PA). The two groups were compared through multivariate analyses, while multiple regression analysis was conducted to determine whether physical activity predict specific outcomes.

RESULTS

No significant differences were found between the two groups in terms of last Body Mass Index (BMI) before illness, BMI at admission and disease duration, while a difference emerged in delta BMI(rapidity of weight loss), significantly higher in high-PA group (p = 0.021). Significant differences were observed in Free triiodothyronine- (p < 0.001), Free thyroxine (p = 0.046), Follicle-stimulating hormone (p = 0.019), Luteinising hormone (p = 0.002) levels, with values remarkably lower in high-PA group. Concerning psychopathological scales, the high-PA group showed worst Children's Global Assessment Scale (CGAS) scores (p = 0.035). Regression analyses revealed that higher PA predicts higher delta BMI (p = 0.021), presence of amenorrhea (p = 0.003), lower heart rate (p = 0.012), lower thyroid (Free triiodothyronine p < 0.001, Free thyroxine p = 0.029) and gynaecological hormones' levels (Follicle-stimulating hormone p = 0.023, Luteinising hormone p = 0.003, 17-Beta estradiol p = 0.041). Concerning psychiatric measures, HPA predicts worst scores at CGAS (p = 0.019), and at scales for evaluation of alexithymia (p = 0.028) and depression (p = 0.004).

CONCLUSIONS

Results suggest that high levels of physical activity in acute AN associate with worst clinical conditions at admission, especially in terms of endocrinological and medical features.

LEVEL OF EVIDENCE

Level III.

Anorexia nervosa, conduct disorder, and the juvenile justice system: a case of applying traditional treatment modalities in a non-traditional setting

Background

Anorexia Nervosa is highly comorbid with depressive, anxiety, and obsessive-compulsive spectrum disorders. However, it has not previously been reported as comorbid with antisocial personality traits, except when substance use disorder is also identified. We present an unusual case of a patient with resistant anorexia nervosa and comorbid conduct disorder. This case was also unique in that the juvenile justice system was involved during treatment.

Case presentation

A 13-year-old female was admitted to our pediatric hospital for the treatment of anorexia nervosa. She had a history of violent behaviors toward family members, often jeopardizing her care. During hospitalization, she physically attacked a physician on her care team shortly before she transitioned to an eating disorders treatment program. She was diagnosed with conduct disorder, and following discharge, she attacked her father in a premeditated act. This led to her entry into the juvenile justice system. While under the custody of the juvenile justice system, she was readmitted to our hospital for further treatment of anorexia nervosa. Our treatment strategy included psychotropics, positive reinforcement, close interdisciplinary coordination among the various hospital teams, and the juvenile justice system. Following discharge from her second hospitalization back to the juvenile detention system, our patient maintained a healthy weight and appeared to show improvements in the cognitive distortions related to her eating disorder.

Conclusions

To our knowledge, this is the first reported successful treatment of an individual with resistant anorexia nervosa and conduct disorder. It was likely a combination of weight gain, psychotropic medications, and the structured milieu provided by the juvenile justice system that led to the effective treatment of our patient. This case illustrates that a non-traditional healthcare setting can be an asset to treatment through persistence and close collaboration across institutions.

Untangling the associations between generalized anxiety and body dissatisfaction: The mediating effects of social physique anxiety among collegiate men and women

Researchers disagree on which types of anxiety influence body dissatisfaction and how gender (cisgender men vs. cisgender women) may impact these associations. Specifically, little is known about how generalized anxiety and social physique anxiety combine to predict body dissatisfaction in men and women. The purpose of the present study was to explore a moderated mediation model in which the relationships between generalized anxiety and body dissatisfaction (drive for thinness and drive for muscularity) were mediated by social physique anxiety and moderated by gender. Data from 423 U.S. college students (n = 259 women) were analyzed using multigroup structural equation modeling. Generalized anxiety was positively associated with social physique anxiety, and this association was significantly stronger for men than for women. Neither social physique anxiety nor generalized anxiety were associated with drive for muscularity. Social physique anxiety was positively and significantly associated with drive for thinness equally for men and women and emerged as a significant mediator. These results highlight gender differences/similarities in body image and suggest drive for thinness and social physique anxiety may have a common factor of generalized anxiety. When helping clients who suffer with body dissatisfaction, clinicians and researchers may wish to focus on generalized anxiety (and not just social physique anxiety).

Comorbid obsessive-compulsive disorder in individuals with eating disorders: An epidemiological meta-analysis

The present study aimed to provide a precise, meta-analytic estimate of the prevalence of obsessive-compulsive disorder (OCD) amongst those with a current primary eating disorder (ED) diagnosis, and to isolate its predictors. An online search of PubMed and PsycINFO was conducted with a Boolean search phrase incorporating keywords related to OCD, EDs, comorbidity, prevalence, and epidemiology, complemented by references coded from related review articles and contact with experts in the field. Articles were included if they (a) reported an observational study examining current ED diagnoses, (b) used a semi-structured or structured diagnostic interview for OCD and ED diagnosis, (c) applied DSM or ICD criteria, (d) included adolescent or adult samples (age > 12), (e) included patient or community samples, and (f) reported lifetime or current OCD comorbidity. From the 846 articles identified, 35 lifetime and 42 current estimates were calculated. OCD prevalence was extracted from each study for each ED diagnostic category, along with eleven additional potential moderators. Analyses revealed an aggregate lifetime OCD prevalence of 13.9% CI_95% [10.4 to 18.1] and current OCD prevalence of 8.7% CI_95% [5.8 to 11.8] across EDs. Moderator analyses revealed the prevalence of and risk for OCD in EDs to be greatest in anorexia nervosa binge-eating purging type (ANBP). Further, OCD is most prevalent amongst patient samples than samples recruited from the community.

Genetic and environmental influences on posttraumatic stress disorder symptoms and disinhibited eating behaviors

Posttraumatic stress disorder (PTSD) and eating disorders (ED) frequently co-occur, but the mechanisms underlying this association remain unclear. EDs are characterized by features of maladaptive eating behaviors including disinhibited eating and cognitive dietary restraint. Identifying the genetic overlap between PTSD symptoms and maladaptive eating behaviors may elucidate biological mechanisms and potential treatment targets. A community sample of 400 same-sex twins (102 monozygotic and 98 dizygotic pairs) completed the PTSD Checklist-Civilian (PCL-C) for PTSD symptoms and the Three-Factor Eating Questionnaire-Reduced (TFEQ-R18) for eating behaviors (uncontrolled eating, emotional eating, and cognitive dietary restraint). We used biometric modeling to examine the genetic and environmental relationships between PCL-C and TFEQ-R18 total and subscales scores. Heritability was estimated at 48% for PTSD symptoms and 45% for eating behavior overall. Bivariate models revealed a significant genetic correlation between PTSD symptoms and eating behavior overall (r_g =.34; CI:.07,.58) and Uncontrolled Eating (r_g =.53; CI:.24,.84), and a significant environmental correlation between PTSD symptoms and Emotional Eating (r_e =.30; CI:.12,.45). These findings suggest the influence of common etiology. Future research and clinical efforts should focus on developing integrated treatments.

Suppression of food restriction-evoked hyperactivity in activity-based anorexia animal model through glutamate transporters GLT-1 at excitatory synapses in the hippocampus

Severe voluntary food restriction is the defining symptom of anorexia nervosa (AN), but anxiety and excessive exercise are maladaptive symptoms that contribute significantly to the severity of AN and which individuals with AN have difficulty suppressing. We hypothesized that the excitability of hippocampal pyramidal neurons, known to contribute to anxiety, leads to the maladaptive behavior of excessive exercise. Conversely, since glutamate transporter GLT-1 dampens the excitability of hippocampal pyramidal neurons through the uptake of ambient glutamate and suppression of the GluN2B-subunit containing NMDA receptors (GluN2B-NMDARs), GLT-1 may contribute toward dampening excessive exercise. This hypothesis was tested using the mouse model of AN, called activity-based anorexia (ABA), whereby food restriction evokes the maladaptive behavior of excessive wheel running (food restriction-evoked running, FRER). We tested whether individual differences in ABA vulnerability of mice, quantified based on FRER, correlated with individual differences in the levels of GLT-1 at excitatory synapses of the hippocampus. Electron microscopic immunocytochemistry (EM-ICC) was used to quantify GLT-1 levels at the excitatory synapses of the hippocampus. The FRER seen in individual mice varied more than 10-fold, and Pearson correlation analyses revealed a strong negative correlation (p = .02) between FRER and GLT-1 levels at the axon terminals of excitatory synapses and at the surrounding astrocytic plasma membranes. Moreover, synaptic levels of GluN2B-NMDARs correlated strongly with GLT-1 levels at perisynaptic astrocytic plasma membranes. There is at present no accepted pharmacotherapy for AN, and little is known about the etiology of this deadly illness. Current findings suggest that drugs increasing GLT-1 expression may reduce AN severity through the reduction of GluN2B-NMDAR activity.

Physical Activity in Eating Disorders: A Systematic Review

Abnormally high levels of physical activity have been documented throughout the literature in patients with eating disorders (ED), especially those diagnosed with anorexia nervosa (AN). Yet no clear definition, conceptualization, or treatment of the problematic use of physical activity (PPA) in ED patients exists. The aim of this review is to propose a new classification of PPA, report the prevalence, triggers, predictors, maintainers and other related factors of PPA in ED patients, in addition to proposing a comprehensive model of the development of PPA in AN. A total of 47 articles, retrieved from Medline and Web of Science, met the inclusion criteria and were included in the analysis. As a result, the new approach of PPA was divided into two groups (group 1 and group 2) according to the dimension (quantitative vs qualitative approach) of physical activity that was evaluated. The prevalence of PPA in ED was reported in 20 out of 47 studies, the comparison of PPA between ED versus controls in 21 articles, and the links between PPA and psychological factors in ED in 26 articles, including depression (16/26), anxiety (13/26), obsessive–compulsiveness (9/26), self-esteem (4/26), addictiveness (1/26), regulation and verbal expression of emotions (1/26) and anhedonia (1/26). The links between PPA and ED symptomatology, PPA and weight, body mass index (BMI) and body composition in ED, PPA and age, onset, illness duration and lifetime activity status in ED, PPA and ED treatment outcome were reported in 18, 15, 7, 5 articles, respectively. All of the factors have been systematically clustered into group 1 and group 2. Results focused more on AN rather than BN due to the limited studies on the latter. Additionally, a model for the development of PPA in AN patients was proposed, encompassing five periods evolving into three clinical stages. Thus, two very opposite components of PPA in AN were suggested: voluntarily PPA increased in AN was viewed as a conscious strategy to maximize weight loss, while involuntarily PPA increased proportionally with weight-loss, indicating that exercise might be under the control of a subconscious biological drive and involuntary cognition.

A pilot randomized controlled trial of omega-3 fatty acid supplementation for the treatment of anxiety in adolescents with anorexia nervosa

OBJECTIVE

To evaluate the effectiveness and tolerability of omega-3 polyunsaturated fatty acid (PUFA) supplementation for treatment of trait anxiety among adolescent females with restrictive anorexia nervosa (AN).

METHOD

A pilot double-blind, placebo-controlled randomized trial of adolescent females with AN (N = 24) entering Partial Hospitalization Program (PHP) from January 2015 to February 2016. Participants were randomized to four daily PUFA (2,120 mg eicosapentaenoic acid/600 mg docosohexaenoic acid) or placebo capsules for 12 weeks. A 9-item questionnaire of side effect frequency assessed medication tolerability. The Beck Anxiety Inventory-Trait measured anxiety at baseline, 6, and 12 weeks. Linear mixed models evaluated associations between randomization group and study outcomes. Twenty-two and 18 participants completed 6 and 12 weeks of data collection, respectively.

RESULTS

Medication side effect scores were low and were not significantly different between randomization groups at Week 6 (p = .20) or 12 (p = .41). Mean trait anxiety score significantly (p < .01) decreased from baseline to 12 weeks in both groups, and the rate of change over the course of time did not differ between omega-3 PUFA and placebo groups (p = .55).

CONCLUSION

Omega-3 PUFA supplementation was well tolerated in adolescent females with AN. Although power to detect differences was limited, we found no evidence that omega-3 PUFA benefited anxiety beyond nutritional restoration.

Anorexia Nervosa, Anxiety, and the Clinical Implications of Rapid Refeeding

The current study aimed to examine the temporal relationship between anxiety symptoms and weight gain for adolescents with anorexia nervosa over the course of an inpatient admission targeting weight restoration through rapid refeeding. Participants were 31 females presenting to a specialist inpatient unit. Psychometric assessments using standardized procedures were conducted to assess co-morbid anxiety diagnoses, and eating disorder symptom severity at admission and discharge. Study protocols were completed on a weekly basis over the course of their admission and were compared with weekly BMI change. Multiple mixed-effects linear models with random intercepts were used to assess change in weight status and psychological variables. Results indicated a reduction in anxiety over the course of hospitalization; however, there was no evidence to support a relationship between anxiety change and weight restoration. The clinical implications of these results are discussed and directions for future research recommended.

Global/local processing style: Explaining the relationship between trait anxiety and binge eating

OBJECTIVE

Anxiety is a risk factor for disordered eating, but the mechanisms by which anxiety promotes disordered eating are poorly understood. One possibility is local versus global cognitive processing style, defined as a relative tendency to attend to details at the expense of the "big picture." Anxiety may narrow attention, in turn, enhancing local and/or compromising global processing. We examined relationships between global/local processing style, anxiety, and disordered eating behaviors in a transdiagnostic outpatient clinical sample. We hypothesized that local (vs. global) processing bias would mediate the relationship between anxiety and disordered eating behaviors.

METHOD

Ninety-three participants completed the eating disorder examination-questionnaire (EDE-Q), State-Trait Anxiety Inventory (STAI)-trait subscale, and the Navon task (a test of processing style in which large letters are composed of smaller letters both congruent and incongruent with the large letter). The sample was predominantly female (95%) with a mean age of 27.4 years (SD = 12.1 years).

RESULTS

Binge eating, but not fasting, purging, or excessive exercise, was correlated with lower levels of global processing style. There was a significant indirect effect between anxiety and binge eating via reduced global level global/local processing.

DISCUSSION

In individuals with disordered eating, being more generally anxious may encourage a detailed-oriented bias, preventing individuals from maintaining the bigger picture and making them more likely to engage in maladaptive behaviors (e.g., binge eating).

Patterns of medical utilization before the first hospitalization for women with anorexia nervosa in Taiwan

OBJECTIVE

The aim of this paper was to analyze medical utilization patterns of female patients with anorexia nervosa before their first inpatient care visit for anorexia nervosa using the National Health Insurance Research Database (NHIRD) of Taiwan.

METHOD

We selected female anorexia nervosa patients (n=239) and control participants hospitalized for peptic ulcers (n=478) or appendectomy (n=478) who were matched by age and incident year from two subsets of the NHIRD. The number of visits, specialists, diagnosis distribution, and selected procedures used in ambulatory services during the 2-year period before the index admission were identified and compared. Healthcare service expenditures were also analyzed.

RESULTS

Compared to the control groups, the female anorexia nervosa patients used more outpatient services (anorexia nervosa, 58.6±45.0 visits; peptic ulcers, 45.3±37.3 visits; appendectomy, 32.5±26.0 visits), mainly due to psychiatric visits. Anorexia nervosa patients were more likely to have received a diagnosis of digestive, endocrine/metabolic, and mental disorders than patients in the control groups. Although nearly equal percentages of patients in the three groups had obtained a diagnosis of a digestive disease, anorexia nervosa patients received digestive disease diagnoses with greater frequency.

CONCLUSIONS

We posit that the various physical symptoms of anorexia nervosa patients and physicians' low level of suspicion of anorexia nervosa led to delayed diagnoses and greater medical utilization than that of the controls groups. Education to raise awareness of anorexia nervosa and other eating disorders among physicians is warranted.

Differential diagnosis of anorexia nervosa and obsessive compulsive disorder in a male military veteran

Research on the relationship between military service and eating pathology has yielded mixed findings. Among those of military backgrounds, anorexia nervosa typically presents with co-occurring disorders that complicate diagnosis and treatment. The purpose of this paper is to present a case report of a retired Navy midshipman. The patient sought treatment for obsessive compulsive disorder (OCD), but his assessment revealed the primary pathology to be anorexia nervosa. This case illustrates ways in which military life may contribute to eating pathology and the complex overlap and differential diagnosis of anorexia nervosa and OCD.

Enlargement of Axo-Somatic Contacts Formed by GAD-Immunoreactive Axon Terminals onto Layer V Pyramidal Neurons in the Medial Prefrontal Cortex of Adolescent Female Mice Is Associated with Suppression of Food Restriction-Evoked Hyperactivity and Resilience to Activity-Based Anorexia

Many, but not all, adolescent female mice that are exposed to a running wheel while food restricted (FR) become excessive wheel runners, choosing to run even during the hours of food availability, to the point of death. This phenomenon is called activity-based anorexia (ABA). We used electron microscopic immunocytochemistry to ask whether individual differences in ABA resilience may correlate with the lengths of axo-somatic contacts made by GABAergic axon terminals onto layer 5 pyramidal neurons (L5P) in the prefrontal cortex. Contact lengths were, on average, 40% greater for the ABA-induced mice, relative to controls. Correspondingly, the proportion of L5P perikaryal plasma membrane contacted by GABAergic terminals was 45% greater for the ABA mice. Contact lengths in the anterior cingulate cortex correlated negatively and strongly with the overall wheel activity after FR (R = -0.87, P < 0.01), whereas those in the prelimbic cortex correlated negatively with wheel running specifically during the hours of food availability of the FR days (R = -0.84, P < 0.05). These negative correlations support the idea that increases in the glutamic acid decarboxylase (GAD) terminal contact lengths onto L5P contribute toward ABA resilience through suppression of wheel running, a behavior that is intrinsically rewarding and helpful for foraging but maladaptive within a cage.

Does anxiety improve during weight restoration in anorexia nervosa? A systematic review

Weight restoration is considered a principal outcome for treatment of Anorexia Nervosa (AN) due to the significant physiological disturbances resultant from acute states of malnutrition. Treatment outcomes for populations with AN are relatively poor, with increasing evidence suggesting that weight restoration alone is insufficient for long-term recovery. Research aimed at understanding the psychological sequaele of AN, in particular during weight restoration, nevertheless remain scarce. This systematic review aimed to evaluate existing research regarding anxiety symptoms during treatment for AN, and the relationship of anxiety symptomology and weight restoration. Twelve articles were identified from a systematic search of three electronic databases (PsycINFO, MEDLINE, and Web of Science), and were eligible for inclusion. Study methodology, results and quality were reviewed. Results regarding change in anxiety symptomology were inconsistent, though evidence did not support a relationship between anxiety change and weight restoration. Reasons for these inconsistencies and limitations of included studies were reviewed. Further research is warranted to elucidate the role of anxiety in AN and its implications for treatment and longer-term outcome.

The plasticity of development: how knowledge of epigenetics may advance understanding of eating disorders

OBJECTIVE

To depict the processes through which animals and human beings engage their environment in continuously evolving states of conflict and cooperation.

METHOD

Descriptive literature review.

RESULTS

Life history outcomes are more relative than they are absolute. Genetic variations play a crucial role, but heavily influencing behavioral outcomes, psychopathology included, are external cues that epigenetically remodel DNA along experience-dependent signaling pathways. The result is phenotypes that either optimize adjustment, or constrain it.

DISCUSSION

Knowledge of epigenetic mechanisms may help shed new light on the origin of maturational phenotypes underlying eating disorders and why adjusting treatments to these realities warrants our attention.

The role of leptin, melanocortin, and neurotrophin system genes on body weight in anorexia nervosa and bulimia nervosa

OBJECTIVE

Although low weight is a key factor contributing to the high mortality in anorexia nervosa (AN), it is unclear how AN patients sustain low weight compared with bulimia nervosa (BN) patients with similar psychopathology. Studies of genes involved in appetite and weight regulation in eating disorders have yielded variable findings, in part due to small sample size and clinical heterogeneity. This study: (1) assessed the role of leptin, melanocortin, and neurotrophin genetic variants in conferring risk for AN and BN; and (2) explored the involvement of these genes in body mass index (BMI) variations within AN and BN.

METHOD

Our sample consisted of 745 individuals with AN without a history of BN, 245 individuals with BN without a history of AN, and 321 controls. We genotyped 20 markers with known or putative function among genes selected from leptin, melanocortin, and neurotrophin systems.

RESULTS

There were no significant differences in allele frequencies among individuals with AN, BN, and controls. AGRP rs13338499 polymorphism was associated with lowest illness-related BMI in those with AN (p = 0.0013), and NTRK2 rs1042571 was associated with highest BMI in those with BN (p = 0.0018).

DISCUSSION

To our knowledge, this is the first study to address the issue of clinical heterogeneity in eating disorder genetic research and to explore the role of known or putatively functional markers in genes regulating appetite and weight in individuals with AN and BN. If replicated, our results may serve as an important first step toward gaining a better understanding of weight regulation in eating disorders.

α4βδ-GABAARs in the hippocampal CA1 as a biomarker for resilience to activity-based anorexia

Anorexia nervosa (AN) is a psychiatric illness characterized by restricted eating and an intense fear of gaining weight. Most individuals with AN are females, diagnosed first during adolescence, 40-80% of whom exhibit excessive exercise, and an equally high number with a history of anxiety disorder. We sought to determine the cellular basis for individual differences in AN vulnerability by using an animal model, activity-based anorexia (ABA), that is induced by combining food restriction (FR) with access to a running wheel that allows voluntary exercise. Previously, we showed that by the fourth day of FR, the ABA group of adolescent female rats exhibit >500% greater levels of non-synaptic α4βδ-GABAARs at the plasma membrane of hippocampal CA1 pyramidal cell spines, relative to the levels found in age-matched controls that are not FR and without wheel access. Here, we show that the ABA group exhibits individual differences in body weight loss, with some losing nearly 30%, while others lose only 15%. The individual differences in weight loss are ascribable to individual differences in wheel activity that both precedes and concurs with days of FR. Moreover, the increase in activity during FR correlates strongly and negatively with α4βδ-GABAAR levels (R=-0.9, p<0.01). This negative correlation is evident within 2days of FR, before body weight loss approaches life-threatening levels for any individual. These findings suggest that increased shunting inhibition by α4βδ-GABAARs in spines of CA1 pyramidal neurons may participate in the protection against the ABA-inducing environmental factors of severe weight loss by suppressing excitability of the CA1 pyramidal neurons which, in turn, is related indirectly to suppression of excessive exercise. The data also indicate that, although exercise has many health benefits, it can be maladaptive to individuals with low levels of α4βδ-GABAARs in the CA1, particularly when combined with FR.

Adolescent female C57BL/6 mice with vulnerability to activity-based anorexia exhibit weak inhibitory input onto hippocampal CA1 pyramidal cells

Anorexia nervosa (AN) is an eating disorder characterized by self-imposed severe starvation and often linked with excessive exercise. Activity-based anorexia (ABA) is an animal model that reproduces some of the behavioral phenotypes of AN, including the paradoxical increase in voluntary exercise following food restriction (FR). Although certain rodents have been used successfully in this animal model, C57BL/6 mice are reported to be less susceptible to ABA. We re-examined the possibility that female C57BL/6 mice might exhibit ABA vulnerability during adolescence, the developmental stage/sex among the human population with particularly high AN vulnerability. After introducing the running wheel to the cage for 3 days, ABA was induced by restricting food access to 1h per day (ABA1, N=13) or 2 h per day (ABA2, N=10). All 23 exhibited increased voluntary wheel running (p<0.005) and perturbed circadian rhythm within 2 days. Only one out of five survived ABA1 for 3 days, while 10 out of 10 survived ABA2 for 3 days and could subsequently restore their body weight and circadian rhythm. Exposure of recovered animals to a second ABA2 induction revealed a large range of vulnerability, even within littermates. To look for the cellular substrate of differences in vulnerability, we began by examining synaptic patterns in the hippocampus, a brain region that regulates anxiety as well as plasticity throughout life. Quantitative EM analysis revealed that CA1 pyramidal cells of animals vulnerable to the second ABA2 exhibit less GABAergic innervation on cell bodies and dendrites, relative to the animals resilient to the second ABA (p<0.001) or controls (p<0.05). These findings reveal that C57BL/6J adolescent females can be used to capture brain changes underlying ABA vulnerability, and that GABAergic innervation of hippocampal pyramidal neurons is one important cellular substrate to consider for understanding the progression of and resilience to AN.

Common psychiatric disorders and caffeine use, tolerance, and withdrawal: an examination of shared genetic and environmental effects

BACKGROUND

Previous studies examined caffeine use and caffeine dependence and risk for the symptoms, or diagnosis, of psychiatric disorders. The current study aimed to determine if generalized anxiety disorder (GAD), panic disorder, phobias, major depressive disorder (MDD), anorexia nervosa (AN), or bulimia nervosa (BN) shared common genetic or environmental factors with caffeine use, caffeine tolerance, or caffeine withdrawal.

METHOD

Using 2,270 women from the Virginia Adult Twin Study of Psychiatric and Substance Use Disorders, bivariate Cholesky decomposition models were used to determine if any of the psychiatric disorders shared genetic or environmental factors with caffeine use phenotypes.

RESULTS

GAD, phobias, and MDD shared genetic factors with caffeine use, with genetic correlations estimated to be 0.48, 0.25, and 0.38, respectively. Removal of the shared genetic and environmental parameter for phobias and caffeine use resulted in a significantly worse fitting model. MDD shared unique environmental factors (environmental correlation=0.23) with caffeine tolerance; the genetic correlation between AN and caffeine tolerance and BN and caffeine tolerance were 0.64 and 0.49, respectively. Removal of the genetic and environmental correlation parameters resulted in significantly worse fitting models for GAD, phobias, MDD, AN, and BN, which suggested that there was significant shared liability between each of these phenotypes and caffeine tolerance. GAD had modest genetic correlations with caffeine tolerance, 0.24, and caffeine withdrawal, 0.35.

CONCLUSIONS

There was suggestive evidence of shared genetic and environmental liability between psychiatric disorders and caffeine phenotypes. This might inform us about the etiology of the comorbidity between these phenotypes.

Brain-derived neurotrophic factor and neuropsychiatric disorders

Brain derived neurotrophic factor (BDNF) is the most prevalent growth factor in the central nervous system (CNS). It is essential for the development of the CNS and for neuronal plasticity. Because BDNF plays a crucial role in development and plasticity of the brain, it is widely implicated in psychiatric diseases. This review provides a summary of clinical and preclinical evidence for the involvement of this ubiquitous growth factor in major depressive disorder, schizophrenia, addiction, Rett syndrome, as well as other psychiatric and neurodevelopmental diseases. In addition, the review includes a discussion of the role of BDNF in the mechanism of action of pharmacological therapies currently used to treat these diseases, such antidepressants and antipsychotics. The review also covers a critique of experimental therapies such as BDNF mimetics and discusses the value of BDNF as a target for future drug development.

Cancer and anorexia nervosa in the adolescence: a family-based systemic intervention

Objective. Anorexia nervosa is difficult to diagnose in cancer patients since weight loss, aversion for food, and eating disturbances are frequent in patients undergoing chemotherapy and radiotherapy. Nevertheless, efforts are mandatory to recognize and manage this condition which may occur also in cancer patients with a special regard to adolescents. Methods. Through the clinical history of Anna, a 15-year-old adolescent with advanced cancer, we describe the effectiveness of a family-based systemic intervention to manage anorexia nervosa occurring in concomitance to osteosarcoma. Results. Through a two-year psychotherapy period involving different techniques applied to the whole family such as family genogram, family collage, and sculpture of family time, Anna was relieved from her condition. Conclusions. Upon early diagnosis and appropriate treatment, anorexia nervosa can be effectively approached in adolescent cancer patients. The presence of a life-threatening medical condition such as cancer may provide motivation for a patient to control disordered eating behavior in the context of an appropriate family-based systemic intervention. The general frame of anorexia occurring in cancer-bearing adolescents is reviewed and discussed.

Generalized anxiety disorder and anorexia nervosa: evidence of shared genetic variation

BACKGROUND

Previous studies have indicated a high prevalence of generalized anxiety disorder (GAD) in women with anorexia nervosa (AN). However, the shared genetic and environmental components of these disorders have not been explored. This study seeks to elucidate the shared genetic and environmental components between GAD and AN.

METHOD

Using 2,083 women from the Virginia Adult Twin Study of Psychiatric and Substance Use Disorders, structural equation modeling was used to obtain maximum likelihood estimates of the environmental genetic, shared and unique environmental components in 496 women with GAD, 47 women with AN, 43 women with GAD + AN, and 1,497 women without GAD or AN.

RESULTS

Results show that the heritability of GAD was 0.32 and AN was 0.31, and the genetic correlation between the two disorders was 0.20, indicating a modest genetic contribution to their comorbidity. Unique environment estimate was 0.68 for GAD and 0.69 for AN, with a unique environmental correlation of 0.18. All common environmental parameters were estimated at zero.

CONCLUSIONS

The modest shared genetic and unique environmental liability to both disorders may help explain the high prevalence of GAD in women with AN. This knowledge could help in the treatment and prevention of comorbid disorders.