Eating disorders and hyperactivity: a psychobiological perspective

The Impact of High Levels of Compensatory Exercise on Treatment Outcomes in Threshold and Subthreshold Bulimia Nervosa

Bulimia nervosa (BN) and other specific feeding or eating disorders with subthreshold BN symptoms (OSFED-BN) are characterized by recurrent binge eating episodes accompanied by compensatory behaviors, including excessive exercise. We aimed to examine the role of compensatory exercise on several clinical disorder-related variables and the treatment outcomes. The sample included 478 patients diagnosed with either BN or OSFED-BN admitted for a 16-week eating disorder-specific treatment program. A battery of questionnaires was administered to evaluate eating and general psychopathology, and personality traits. Other clinical disorder-related data, including levels of compensatory exercise, were assessed through a semi-structured clinical interview. Between-group comparisons of compensatory exercise levels were analyzed, as a predictive model of risk of poor treatment outcomes. Path analysis was conducted using structural equation models to estimate the direct and indirect effects between the main variables. Higher levels of self-reported compensatory exercise were associated with greater eating psychopathology, general psychopathology, and more dysfunctional personality traits and were a predictor of poor treatment outcomes. Additionally, these levels achieved a mediating role in several paths contributing to a higher likelihood of a poor outcome. Further research is required to determine how psychotherapeutic approaches can be optimized to adequately include adaptive exercise for these patients.

Sensor technology in eating disorders research: A systematic review

OBJECTIVE

Sensor technologies offer exciting potential to objectively measure psychopathological correlates of eating pathology and eating disorder (ED) research utilizing sensors has rapidly proliferated in the past several years. The aims of the present review are: (1) characterize the types of sensors that have been utilized in ED research, (2) identify the psychopathological factors relevant to EDs that have been assessed using sensors, (3) describe the data supporting the validity and reliability of these sensors, (4) discuss limitations associated with these sensors, and (5) identify gaps that persist within the ED literature with regard to use of sensor technologies.

METHOD

A systematic search was conducted of PubMed, PsycINFO, Web of Science, ProQuest, and "gray" literature sources. Eligible publications were empirical studies that utilized sensors to measure at least one psychological variable among clinical ED populations.

RESULTS

Sensors have been utilized with ED samples to measure eating behaviors, physical activity, sleep, autonomic nervous system activity, eyeblink startle response, visual attention, and visual-haptic object integration. The reliability and validity of these sensors varies widely and there are a number of significant gaps that remain in the literature with regard to the types of sensors utilized, context in which sensors have been used, and populations studied.

DISCUSSION

The existing literature utilizing sensors within ED research largely support the feasibility and acceptability of these tools. Sensors should continue to be utilized within the field, with a specific focus on examining the reliability and validity of these tools within ED samples and increasing the diversity of samples studied.

PUBLIC SIGNIFICANCE STATEMENT

Sensor technologies, such as those included in modern smartwatches, offer new opportunities to measure factors that may maintain or contribute to symptoms of eating disorders. This article describes the types of sensors that have been used in eating disorders research, challenges that may arise in using these sensors, and discusses new applications of these sensors that may be pursued in future research.

Psychometric properties of the Compulsive Exercise Test in a large sample of female adolescent and adult inpatients with anorexia nervosa and bulimia nervosa

OBJECTIVE

The Compulsive Exercise Test (CET) was developed to assess compulsive exercise in patients with eating disorders (EDs), but originally validated in a nonclinical sample, and psychometric properties were only investigated in small clinical samples. Therefore, the aim of this study was to examine its psychometric properties in a large clinical sample of adolescent and adult inpatients with anorexia nervosa and bulimia nervosa.

METHOD

A sample of 2,535 German female inpatients with EDs completed the CET and other instruments at admission and discharge. Factor structure (confirmatory [CFA] and exploratory factor analyses [EFA]), internal consistency and construct validity, measurement invariance across age and diagnostic groups, group comparisons of means, as well as sensitivity to change during treatment were assessed.

RESULTS

The CET showed high internal consistency, very good construct validity, and sensitivity to change. CFA indicated a better fit of four-factor and three-factor solutions compared to the original five-factor model. However, subsequent EFA identified an optimum for a five-factor model. Only three subscales were satisfactorily invariant to measurement, but not the CET total score. Only small differences in scores between patient groups were observed.

DISCUSSION

Results support internal consistency, construct validity, and sensitivity to change, whereas factor structure remains inconclusive, questioning the theoretical basis of the CET. There is limited support for using the lack of enjoyment subscale, and only moderate support for using the rigidity subscale in patients with EDs. It is recommended to further explore and/or revise the original CET, including investigation in other samples, for example, male samples.

Rethinking the Approach to Preclinical Models of Anorexia Nervosa

PURPOSE OF REVIEW

The goal of this review is to describe how emerging technological developments in pre-clinical animal research can be harnessed to accelerate research in anorexia nervosa (AN).

RECENT FINDINGS

The activity-based anorexia (ABA) paradigm, the best characterized animal model of AN, combines restricted feeding, excessive exercise, and weight loss. A growing body of evidence supports the idea that pathophysiological weight loss in this model is due to cognitive inflexibility, a clinical feature of AN. Targeted manipulations that recapitulate brain changes reported in AN - hyperdopaminergia or hyperactivity of cortical inputs to the nucleus accumbens - exacerbate weight loss in the ABA paradigm, providing the first evidence of causality. The power of preclinical research lies in the ability to assess the consequences of targeted manipulations of neuronal circuits that have been implicated in clinical research. Additional paradigms are needed to capture other features of AN that are not seen in ABA.

The Central Role of Hypothermia and Hyperactivity in Anorexia Nervosa: A Hypothesis

Typically, the development of anorexia nervosa (AN) is attributed to psycho-social causes. Several researchers have recently challenged this view and suggested that hypothermia and hyperactivity (HyAc) are central to AN. The following hypothesis will attempt to clarify their role in AN. Anorexia nervosa patients (ANs) have significantly lower core temperatures (T_core) compared to healthy controls (HCs). This reduced temperature represents a reset T_core that needs to be maintained. However, ANs cannot maintain this T_core due primarily to a reduced basal metabolic rate (BMR); BMR usually supplies heat to sustain T_core. Therefore, to generate the requisite heat, ANs revert to the behavioral-thermoregulatory strategy of HyAc. The majority of ANs (~89%) are reportedly HyAc. Surprisingly, engagement in HyAc is not motivated by a conscious awareness of low T_core, but rather by the innocuous sensation of "cold- hands" frequently reported by ANs. That is, local hand-thermoreceptors signal the brain to initiate HyAc, which boosts perfusion of the hands and alters the sensation of "cold-discomfort" to one of "comfort." This "rewarding" consequence encourages repetition/habit formation. Simultaneously, hyperactivity increases the availability of heat to assist with the preservation of T_core. Additionally, HyAc induces the synthesis of specific brain neuromodulators that suppress food intake and further promote HyAc; this outcome helps preserve low weight and perpetuates this vicious cycle. Based on this hypothesis and supported by rodent research, external heat availability should reduce the compulsion to be HyAc to thermoregulate. A reduction in HyAc should decrease the production of brain neuromodulators that suppress appetite. If verified, hopefully, this hypothesis will assist with the development of novel treatments to aid in the resolution of this intractable condition.

Efficacy of a Specialized Group Intervention for Compulsive Exercise in Inpatients with Anorexia Nervosa: A Randomized Controlled Trial

INTRODUCTION

Treatment of compulsive exercise is recognized as a key unmet challenge in the treatment of anorexia nervosa (AN). To address this challenge, we developed the manualized group intervention "healthy exercise behavior" (HEB). This study evaluates the efficacy of HEB for the reduction of compulsive exercise as add-on to routine inpatient treatment (treatment as usual [TAU]) in a randomized controlled trial.

METHODS

Two hundred and seven adolescent and adult female inpatients with (atypical) AN were randomly allocated to TAU or to additional participation in HEB (TAU + HEB). HEB integrates elements of exercise-based therapy into a cognitive-behavioral approach. Assessments took place at admission, pre-intervention, post-intervention, discharge, and 6 months follow-up. Primary outcome was the severity of compulsive exercise assessed by the Commitment to Exercise Scale between pre- and post-intervention; secondary outcomes were additional aspects of compulsive exercise, assessed by the Compulsive Exercise Test, weight gain, eating disorder and general psychopathology, and emotion regulation.

RESULTS

In intention-to-treat analysis for the primary outcome, the TAU + HEB group showed significantly stronger reductions in the severity of compulsive exercise compared to the TAU group (z = -2.81; p = 0.005; effect size [ES] = -0.3). We also found significantly stronger reductions from admission to discharge (z= 2.62; p = 0.009; ES = -0.43), and from admission to follow-up (z = 2.1; p = 0.035; ES = -0.39). Regarding secondary outcomes, we found significant group differences between pre- and post-intervention in additional aspects of compulsive exercise (z = -2.55; p = 0.011; ES = -0.27). We did not find significant differences regarding weight gain, eating disorder and general psychopathology, and emotion regulation.

CONCLUSIONS

Our intervention proved efficacious in reducing compulsive exercise in inpatients with (atypical) AN.

Severe and Enduring Anorexia Nervosa: Enduring Wrong Assumptions?

To the extent that severe and lasting anorexia nervosa (SE-AN) is defined in terms of refractoriness to the best treatments available, it is mandatory to scrutinize the proven effectiveness of the treatments offered to patients. The array of so-called current evidence-based treatments for anorexia nervosa (AN) encompasses the entire spectrum of treatments ranging from specialized brand-type treatments to new treatments adapted to the specific characteristics of people suffering from AN. However, after several randomized control trials, parity in efficacy is the characteristic among these treatments. To further complicate the landscape of effective treatments, this "tie score" extends to the treatment originally conceived as control conditions, or treatment as usual conditions. In retrospection, one can understand that treatments considered to be the best treatments available in the past were unaware of their possible iatrogenic effects. Obviously, the same can be said of the theoretical assumptions underpinning such treatments. In either case, if the definition of chronicity mentioned above is applied, it is clear that the responsibility for the chronicity of the disorder says more about the flagrant inefficacy of the treatments and the defective assumptions underpinning them, than the nature of the disorder itself. A historical analysis traces the emergence of the current concept of "typical" AN and Hilde Bruch's contribution to it. It is concluded that today's diagnostic criteria resulting from a long process of acculturation distort rather than capture the essence of the disorder, as well as marginalizing and invalidating patients' perspectives.

Differential effects of heat in the phases of the light-dark cycle in the activity-based anorexia model

BACKGROUND

This research builds on the studies on ambient temperature as a key influence in the recovery of rodents exposed to the activity-based anorexia (ABA) model. The ABA model is an experimental paradigm in which rodents under a restricted feeding schedule and with free access to an activity wheel show signs that parallel those of anorexia nervosa in humans.

OBJECTIVE

The present study focuses on the effects of applying heat during the different phases of the dark-light cycle in the activity levels, body weight, food intake, body temperature, and recovery rates of 30 male rats submitted to ABA.

METHOD

After reaching a 20% weight loss criterion, animals were randomly assigned to three experimental conditions: (a) continuous warming, (b) warming exclusively during the light phase, or (c) warming exclusively during the dark phase.

RESULTS

Differential effects were found depending on the modalities of warming: in comparison with either light or dark warming, continuous warming significatively decreased activity, facilitated weight gain, and maintained body temperature. Transient effects of warming were found both in the groups warmed either during light or dark periods exclusively.

DISCUSSION

The results suggest that both light and dark warming did not promote recovery in animals exposed to ABA. Evidence about the beneficial effects of continuous warming are in line with previous research and reinforces adding external heat as a useful tool in the treatment of anorexia nervosa.

Temperature but not leptin prevents semi-starvation induced hyperactivity in rats: implications for anorexia nervosa treatment

The hypothesis linking hyperactivity with weight loss associated hypoleptinemia in anorexia nervosa gained momentum after a study showing that leptin suppressed semi-starvation induced hyperactivity in rats. Alternatively, ambient temperature is a key modulating factor of activity in semi-starved rats. The aim of the study is to compare the efficacy of leptin with increased ambient temperature in the prevention of hyperactivity in semi-starved rats. 74 Sprague-Dawley male rats were employed in two experiments with the difference residing in the length of baseline. After an extended (28 days), or shorter (14 days) baseline with free access to food and the running wheel, housed at 21 °C, animals were either ad-lib feed or food restricted (60% of food ingested during previous week) and infused with same amount of leptin at 21 °C, 25 °C, or vehicle at 21 °C, 25 °C and 32 °C for a week. Animals housed at 32 °C significantly reduced wheel running and weight loss during food restriction while animals given leptin did not yield no differences in activity or weight loss. Moreover, unlike animals housed at 32 °C, body temperature of leptin infused animals housed at 21 °C was significantly reduced during food restriction. Furthermore, leptin treated rats without a preceding stable pattern of activity displayed a severe dysregulation of circadian rhythm in activity and a collapse of body temperature. Housing temperature plays a more critical role than leptin in the regulation of semi-starvation induced hyperactivity in rats, which may be of relevance for the management of hyperactivity in anorexia nervosa.

Rethinking Therapeutic Strategies for Anorexia Nervosa: Insights From Psychedelic Medicine and Animal Models

Anorexia nervosa (AN) has the highest mortality rate of any psychiatric disease, yet available pharmacological treatments are largely ineffective due, in part, to an inadequate understanding of the neurobiological drivers that underpin the condition. The recent resurgence of research into the clinical applications of psychedelic medicine for a range of mental disorders has highlighted the potential for classical psychedelics, including psilocybin, to alleviate symptoms of AN that relate to serotonergic signaling and cognitive inflexibility. Clinical trials using psychedelics in treatment-resistant depression have shown promising outcomes, although these studies are unable to circumvent some methodological biases. The first clinical trial to use psilocybin in patients with AN commenced in 2019, necessitating a better understanding of the neurobiological mechanisms through which psychedelics act. Animal models are beneficial in this respect, allowing for detailed scrutiny of brain function and behavior and the potential to study pharmacology without the confounds of expectancy and bias that are impossible to control for in patient populations. We argue that studies investigating the neurobiological effects of psychedelics in animal models, including the activity-based anorexia (ABA) rodent model, are particularly important to inform clinical applications, including the subpopulations of patients that may benefit most from psychedelic medicine.

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.

Clinical Trials Required to Assess Potential Benefits and Side Effects of Treatment of Patients With Anorexia Nervosa With Recombinant Human Leptin

The core phenotype of anorexia nervosa (AN) comprises the age and stage dependent intertwining of both its primary and secondary (i.e., starvation induced) somatic and mental symptoms. Hypoleptinemia acts as a key trigger for the adaptation to starvation by affecting diverse brain regions including the reward system and by induction of alterations of the hypothalamus-pituitary-“target-organ” axes, e.g., resulting in amenorrhea as a characteristic symptom of AN. Particularly, the rat model activity-based anorexia (ABA) convincingly demonstrates the pivotal role of hypoleptinemia in the development of starvation-induced hyperactivity. STAT3 signaling in dopaminergic neurons in the ventral tegmental area (VTA) plays a crucial role in the transmission of the leptin signal in ABA. In patients with AN, an inverted U-shaped relationship has been observed between their serum leptin levels and physical activity. Albeit obese and therewith of a very different phenotype, humans diagnosed with rare congenital leptin deficiency have starvation like symptoms including hypothalamic amenorrhea in females. Over the past 20 years, such patients have been successfully treated with recombinant human (rh) leptin (metreleptin) within a compassionate use program. The extreme hunger of these patients subsides within hours upon initiation of treatment; substantial weight loss and menarche in females ensue after medium term treatment. In contrast, metreleptin had little effect in patients with multifactorial obesity. Small clinical trials have been conducted for hypothalamic amenorrhea and to increase bone mineral density, in which metreleptin proved beneficial. Up to now, metreleptin has not yet been used to treat patients with AN. Metreleptin has been approved by the FDA under strict regulations solely for the treatment of generalized lipodystrophy. The recent approval by the EMA may offer, for the first time, the possibility to treat extremely hyperactive patients with AN off-label. Furthermore, a potential dissection of hypoleptinemia-induced AN symptoms from the primary cognitions and behaviors of these patients could ensue. Accordingly, the aim of this article is to review the current state of the art of leptin in relation to AN to provide the theoretical basis for the initiation of clinical trials for treatment of this eating disorder.

Beyond the Activity-Based Anorexia Model: Reinforcing Values of Exercise and Feeding Examined in Stressed Adolescent Male and Female Mice

Anorexia nervosa (AN), mostly observed in female adolescents, is the most fatal mental illness. Its core is a motivational imbalance between exercise and feeding in favor of the former. The most privileged animal model of AN is the "activity-based anorexia" (ABA) model wherein partly starved rodents housed with running wheels exercise at the expense of feeding. However, the ABA model bears face and construct validity limits, including its inability to specifically assess running motivation and feeding motivation. As infant/adolescent trauma is a precipitating factor in AN, this study first analyzed post-weaning isolation rearing (PWIR) impacts on body weights and wheel-running performances in female mice exposed to an ABA protocol. Next, we studied through operant conditioning protocols i) whether food restriction affects in a sex-dependent manner running motivation before ii) investigating how PWIR and sex affect running and feeding drives under ad libitum fed conditions and food restriction. Besides amplifying ABA-elicited body weight reductions, PWIR stimulated wheel-running activities in anticipation of feeding in female mice, suggesting increased running motivation. To confirm this hypothesis, we used a cued-reward motivated instrumental task wherein wheel-running was conditioned by prior nose poke responses. It was first observed that food restriction increased running motivation in male, but not female, mice. When fed grouped and PWIR mice were tested for their running and palatable feeding drives, all mice, excepted PWIR males, displayed increased nose poke responses for running over feeding. This was true when rewards were proposed alone or within a concurrent test. The increased preference for running over feeding in fed females did not extend to running performances (time, distance) during each rewarded sequence, confirming that motivation for, and performance during, running are independent entities. With food restriction, mice displayed a sex-independent increase in their preference for feeding over running in both group-housed and PWIR conditions. This study shows that the ABA model does not specifically capture running and feeding drives, i.e. components known to be affected in AN.

MECHANISMS IN ENDOCRINOLOGY: Anorexia nervosa and endocrinology: a clinical update

Anorexia nervosa is a syndrome, that is collections of symptoms, which is not defined by its etiology. The severe cases are intractable. The syndrome is associated with multiple, profound endocrine alterations which may be adaptive, reactive or etiologic. Adaptive changes potentially may be inappropriate in clinical settings such as inpatient intensive re-nutrition or in a setting with somatic comorbidity. Electrolyte levels must be closely monitored during the refeeding process, and the need for weight gain must be balanced against potentially fatal refeeding complications. An important focus of clinical research should be to identify biomarkers associated with different stages of weight loss and re-nutrition combined with psychometric data. Besides well-established peripheral endocrine actions, several hormones also are released directly to different brain areas, where they may exert behavioral and psychogenic actions that could offer therapeutic targets. We need reliable biomarkers for predicting outcome and to ensure safe re-nutrition, however, first of all we need them to explore the metabolism in anorexia nervosa to open new avenues with therapeutic targets. A breakthrough in our understanding and treatment of this whimsical disease remains. Considering this, the aim of the present review is to provide an updated overview of the many endocrine changes in a clinical perspective.

Excessive physical activity in young girls with restrictive-type anorexia nervosa: its role on cardiac structure and performance

PURPOSE

The aim of this study was to investigate the influence of hyperactivity on left ventricular mass (LVM) in Anorexia Nervosa restricting-type (AN-R) and the correlation between LVM and auxologic parameters/circulating hormones.

METHODS

Echocardiography was performed in 44 AN-R girls, subgrouped in 24 hyperactive (ANH+) and 20 non-hyperactive (ANH-), and in 20 controls (HC). LVM indexed to Body Surface Area (LVMi) and LVM indexed to height (LVMh) were calculated.

RESULTS

LVMi and LVMh were significantly lower in the AN-R subjects compared to HC. Moreover, both LVMi and LVMh were higher in the ANH+ than in the ANH-. In the HC, LVMi was higher when compared to the ANH- subjects than to the ANH+. Stepwise analysis revealed that in the ANH+ group, fT4 was the only independent predictor of LVMh, while in the ANH- group, height was the only independent predictors of LVMi.

CONCLUSIONS

Despite its negative influence on disease severity and outcome, hyperactivity from the standpoint of cardiac function makes the LVM of AN-R young girls more similar to HC.

LEVEL OF EVIDENCE

Level III, case-control study.

Compulsive exercise in eating disorders: proposal for a definition and a clinical assessment

BACKGROUND

Compulsive exercise has been recognized as a highly prevalent symptom in eating disorders (ED) for over 100 years and is associated with poor short-term and long-term treatment outcome. Progress in understanding and treatment of compulsive exercise will remain limited as long as no consensus framework for definition and assessment of compulsive exercise exists, as results cannot be compared across clinical studies.Based on existing literature, it was our aim to propose a transdiagnostic definition and a clinical assessment for compulsive exercise, that can be applied to adolescent and adult patients with ED.

METHOD

During a series of meetings of experienced clinicians at a highly specialized hospital for eating disorders, we elaborated a transdiagnostic definition of compulsive exercise in ED. Additionally, we derived a clinical interview for the assessment of compulsive exercise and its different subtypes.

RESULTS

The core criterion when defining and assessing compulsive exercise is a pathologically increased exercise pattern characterized by 1) excessive exercise that a patient feels driven to perform in response to an obsession or according to rules that must be applied rigidly, and 2) exercise that is aimed at preventing or reducing distress or at preventing some dreaded consequence. A second necessary criterion is the physical or psychological burden caused by compulsive exercise, i.e., that it is time-consuming, significantly interferes with the patient's daily routine, occupational functioning or social relationships or is continued despite medical injury, illness, or lack of enjoyment. Insight that compulsive exercise is excessive or unreasonable was added as an optional criterion.Compulsive exercise manifests itself in three different subtypes: 1) vigorous exercise, 2) marked increase in daily movement, or 3) motor restlessness.The above criteria must be met during the past 6 months, together with one of the three subtypes of compulsive exercise.

CONCLUSIONS

The proposed criteria aim to foster the discussion around definition and assessment of compulsive exercise with the goal of reaching an international consensus in the near future.Providing a consistent framework for researchers and clinicians would considerably advance understanding and treatment of compulsive exercise in ED patients.

Excessive exercise among adolescents with eating disorders: examination of psychological and demographic variables

Background While a large number of patients with eating disorders (EDs) engage in excessive exercise (EE), both for weight control and mood regulation, there has been minimal research evaluating the relationship between EE and demographic and psychological factors, especially in adolescent patients. Purpose The goals of this study were to identify the occurrence of EE compared to other ED behaviors and to develop a regression model examining psychological, behavioral and demographic predictors of EE among adolescents with EDs. Methods Demographic and clinical information was determined for 217 adolescent patients in several levels of care (126 outpatient, 61 day program, 28 inpatient) with diagnoses of anorexia nervosa (AN) (24.9%), bulimia nervosa (BN) (25.8%), and eating disorder not otherwise specified (EDNOS) (49.3%). These patients presented to a large ED program and completed a series of questionnaires on admission to the program. Descriptive statistics, t-tests, chi-square analyses and multiple logistic regression were utilized to describe the population of adolescent patients and develop the model for predicting EE. Results Forty-seven percent of patients indicated they participated in EE in the past 4 weeks, compared to 32% for binge eating, 35% for vomiting and 15% for laxative use; 42% of patients with anorexia nervosa participated in EE, compared to 54% with bulimia nervosa and 49% with EDNOS. The regression model that was developed to predict EE, which included factors of depression, anxiety, dietary restraint, age, body mass index (BMI), diagnosis and level of care, correctly classified EE in 71.5% of cases. Dietary restraint and BMI were the two factors found to be significantly associated with EE. Conclusions Forty-seven percent of adolescent patients presenting for treatment of an ED reported participating in EE. This was larger than the numbers of patients reporting other ED behaviors that are commonly assessed, indicating the need for psychoeducation for multidisciplinary treatment teams, assessment, prevention, and clinical treatment services for this problematic behavior. It is important that those who treat patients with ED assess for and monitor EE behaviors that can complicate the treatment.

Validity of Exercise Measures in Adults with Anorexia Nervosa: The EDE, Compulsive Exercise Test and Other Self-Report Scales

OBJECTIVE

Compulsive exercise is a prominent feature for the majority of patients with Anorexia Nervosa (AN), but there is a dearth of research evaluating assessment instruments. This study assessed the concurrent validity of the exercise items of the Eating Disorder Examination (EDE) and Eating Disorder Examination-Questionnaire (EDE-Q), with the Compulsive Exercise Test (CET) and other self-report exercise measures in patients with AN. We also aimed to perform validation of the CET in an adult clinical sample.

METHODS

The sample consisted of 78 adults with AN, recruited for the randomized controlled trial "Taking a LEAP forward in the treatment of anorexia nervosa." At baseline, participants completed the EDE, EDE-Q, CET, Reasons for Exercise Inventory (REI), Commitment to Exercise Scale (CES) and Exercise Beliefs Questionnaire (EBQ). Correlational and regression analyses were performed.

RESULTS

EDE exercise days and exercise time per day were positively correlated with each other and with all CET subscales (except Lack of exercise enjoyment), CES mean, EBQ total and REI total. Exercise time per day was associated with a higher EDE global score. The CET demonstrated good concurrent validity with the CES, the REI and the EBQ. Of the self-reports, the CET explained the greatest variance in eating disorder psychopathology and demonstrated good to excellent reliability in this sample.

DISCUSSION

The EDE and EDE-Q demonstrated good concurrent validity with the CET. Further research is required to evaluate the CET's factor structure in a large clinical sample. However, the CET has demonstrated strong clinical utility in adult patients with AN. © 2016 Wiley Periodicals, Inc.(Int J Eat Disord 2017; 50:533-541).

A systematic review and narrative synthesis of interventions for uncomplicated obesity: weight loss, well-being and impact on eating disorders

OBJECTIVE

Most weight loss research focuses on weight as the primary outcome, often to the exclusion of other physiological or psychological measures. This study aims to provide a holistic evaluation of the effects from weight loss interventions for individuals with obesity by examining the physiological, psychological and eating disorders outcomes from these interventions.

METHODS

Databases Medline, PsycInfo and Cochrane Library (2011-2016) were searched for randomised controlled trials and systematic reviews of obesity treatments (dietary, exercise, behavioural, psychological, pharmacological or surgical). Data extracted included study features, risk of bias, study outcomes, and an assessment of treatment impacts on physical, psychological or eating disorder outcomes.

RESULTS

From 3628 novel records, 134 studies met all inclusion criteria and were evaluated in this review. Lifestyle interventions had the strongest evidence base as a first-line approach, with escalation to pharmacotherapy and bariatric surgery in more severe or complicated cases. Quality of life was the most common psychological outcome measure, and improved in all cases where it was assessed, across all intervention types. Behavioural, psychological and lifestyle interventions for weight loss led to improvements in cognitive restraint, control over eating and binge eating, while bariatric surgery led to improvements in eating behaviour and body image that were not sustained over the long-term.

DISCUSSION

Numerous treatment strategies have been trialled to assist people to lose weight and many of these are effective over the short-term. Quality of life, and to a lesser degree depression, anxiety and psychosocial function, often improve alongside weight loss. Weight loss is also associated with improvements in eating disorder psychopathology and related measures, although overall, eating disorder outcomes are rarely assessed. Further research and between-sector collaboration is required to address the significant overlap in risk factors, diagnoses and treatment outcomes between obesity and eating disorders.

Dopamine and serotonin modulation of motor and non-motor functions of the non-human primate striato-pallidal circuits in normal and pathological states

Thanks to the non-human primate (NHP), we have shown that the pharmacological disturbance of the anterior striatum or of external globus pallidus triggers a set of motivation and movement disorders, depending on the functional subterritory involved. One can, therefore, assume that the aberrant activity of the different subterritories of basal ganglia (BG) could lead to different behavioral disorders in neuropsychiatric disorders as Tourette's syndrome and Parkinson's disease. We are now addressing in the NHP the impact of modulating dopamine or serotonin within the BG on behavioral disorders. Indeed, we have shown a prominent role of serotonergic degeneration within the ventral striatum and caudate nucleus in neuropsychiatric symptoms in de novo PD patients. Of note, the serotonergic modulation of these BG regions in the NHP plays also a critical role in the induction or treatment of behavioral disorders. Given that both dopamine and serotonin are targeted to treat neuropsychiatric disorders, we are studying the effects of modulating dopamine and serotonin transporters in the different territories of the striatum, and more particularly within the ventral striatum on decision-making processing at both behavioral and neuronal levels. Finally, we evidence the need to extend the pharmacological approach to the receptors of these two neuromodulator systems as the use of substances targeting receptor subtypes preferentially localized in the associative and limbic territories of BG could be very effective to specifically improve the behavioral disorders in Parkinson's disease, Gilles de la Tourette syndrome but also in several psychiatric disorders such as depression, anxiety, anorexia, or impulse control disorders.

Physical activity and post-treatment weight trajectory in anorexia nervosa

OBJECTIVE

This study compared an objective measurement of physical activity (PA) in individuals with anorexia nervosa (AN) at low-weight, weight-restored, and post-treatment time points, and also compared PA in AN with that of healthy controls (HC).

METHOD

Sixty-one female inpatients with AN wore a novel accelerometer (the IDEEA) which measured PA at three time points: a) low-weight, b) weight-restored, and c) one month post-hospital discharge. Twenty-four HCs wore the IDEEA at one time point.

RESULTS

Inpatients with AN became more physically active than they were at low-weight at weight restoration and following treatment discharge. Post-treatment patients with AN were more physically active than HCs during the day and less active at night, which was primarily accounted for by amount of time spent on feet, including standing and walking. Greater time spent on feet during the weight-restoration time point of inpatient treatment was associated with more rapid decrease in BMI over the 12 months following treatment discharge. Fidgeting did not differ between patients and controls, did not change with weight restoration, and did not predict post-treatment weight change.

DISCUSSION

Use of a novel accelerometer demonstrated greater PA in AN than in HC. PA following weight restoration in AN, particularly time spent in standing postures, may contribute to weight loss in the year following hospitalization. © 2015 Wiley Periodicals, Inc. (Int J Eat Disord 2016; 49:482-489).

'Feelings stronger than reason': conflicting experiences of exercise in women with anorexia nervosa

BACKGROUND

Individuals with anorexia nervosa frequently feel ambivalent about treatment and weight restoration, and drop out and relapse rates in treatment are high. Increased insight into the function of the eating disorder is considered essential for achieving long-lasting, meaningful change. However, research investigating the functions of anorexia nervosa tends to focus on the role of the disease per se. Distinctions are rarely made across features. In particular, the subjective experience, understanding and sense making of the engagement in compulsive exercise in individuals with anorexia nervosa has received little attention. By using a qualitative methodological approach, this paper aims to expand on prior findings by examining how patients with anorexia nervosa understand and make sense of the experience of exercise in the context of their lives and treatment programme.

METHODS

Semi-structured interviews were conducted with six females, four of whom were former athletes. Transcripts were subjected to interpretative phenomenological analysis (IPA).

RESULTS

Two overarching themes emerged in the analysis of the larger study of which this paper is a part; 'paradoxical functions of exercise' and 'diverging experiences of exercise'. Diverging experiences of exercise is the focus of this paper. Firstly, in spite of being severely underweight and suffering from exhaustion, as well as having a clear awareness of the associated negative health effects, participants were engaged in a continuous cycle of rigorous and excessive exercise, which consumed extensive amounts of time and energy. Secondly, the results demonstrate how exercise routines negatively control and interfere with the participants' involvement in the social world. Thirdly, the manner in which participants speak about their exercise reveals their wording to be characterized by efforts to downplay the extent of their actual immersion in exercise. Issues of control and ambivalence about treatment and recovery can be considered potential triggers for the participants' engagement with exercise. Implicit meanings are elaborated upon and discussed in relation to existing literature.

CONCLUSIONS

The material provides increased insight into the multi-layered meanings of exercise for individuals with anorexia nervosa. It also suggests alternatives to current ways of understanding and approaching exercise that may enable this issue to be addressed in a more meaningful way in therapy. Qualitative approaches can make a valuable contribution to furthering such understanding.

The effect of driven exercise on treatment outcomes for adolescents with anorexia and bulimia nervosa

OBJECTIVE

This study investigated the prevalence of driven exercise (DE) and its role in treatment outcome for adolescents with bulimia nervosa (BN) and anorexia nervosa (AN).

METHOD

Participants were 201 adolescents with an eating disorder (ED) (80 with BN and 121 with AN) presenting for outpatient treatment at two specialist clinics. All adolescents participated in one of two randomized controlled trials. Descriptive statistics were conducted to evaluate the presence and frequency of baseline DE. Exploratory hierarchical regressions were used to evaluate the effect of baseline DE on treatment outcomes.

RESULTS

About 66.3% of adolescents with BN and 23.1% of adolescents with AN presented with baseline DE. The presence of baseline DE predicted significantly worse outcomes for adolescents with AN in terms of ED symptom severity (ps < .004); however, baseline DE did not significantly predict any of the evaluated outcomes for adolescents with BN (ps < .05).

DISCUSSION

The results of this secondary exploratory data suggest that DE is prevalent for adolescents with BN and AN. However, DE may be related to different constructs for adolescents with AN than those with BN, suggesting differences in treatment needs.

Wheel running decreases palatable diet preference in Sprague-Dawley rats

Physical activity has beneficial effects on not only improving some disease conditions but also by preventing the development of multiple disorders. Experiments in this study examined the effects of wheel running on intakes of chow and palatable diet e.g. high fat (HF) or high sucrose (HS) diet in male and female Sprague-Dawley rats. Experiment 1 demonstrated that acute wheel running results in robust HF or HS diet avoidance in male rats. Although female rats with running wheel access initially showed complete avoidance of the two palatable diets, the avoidance of the HS diet was transient. Experiment 2 demonstrated that male rats developed decreased HF diet preferences regardless of the order of diet and wheel running access presentation. Running associated changes in HF diet preference in females, on the other hand, depended on the testing schedule. In female rats, simultaneous presentation of the HF diet and running access resulted in transient complete HF diet avoidance whereas running experience prior to HF diet access did not affect the high preference for the HF diet. Ovariectomy in females resulted in HF diet preference patterns that were similar to those in male rats during simultaneous exposure of HF and wheel running access but similar to intact females when running occurred before HF exposure. Overall, the results demonstrated wheel running associated changes in palatable diet preferences that were in part sex dependent. Furthermore, ovarian hormones play a role in some of the sex differences. These data reveal complexity in the mechanisms underlying exercise associated changes in palatable diet preference.

Physical activity: benefit or weakness in metabolic adaptations in a mouse model of chronic food restriction?

In restrictive-type anorexia nervosa (AN) patients, physical activity is usually associated with food restriction, but its physiological consequences remain poorly characterized. In female mice, we evaluated the impact of voluntary physical activity with/without chronic food restriction on metabolic and endocrine parameters that might contribute to AN. In this protocol, FRW mice (i.e., food restriction with running wheel) reached a crucial point of body weight loss (especially fat mass) faster than FR mice (i.e., food restriction only). However, in contrast to FR mice, their body weight stabilized, demonstrating a protective effect of a moderate, regular physical activity. Exercise delayed meal initiation and duration. FRW mice displayed food anticipatory activity compared with FR mice, which was strongly diminished with the prolongation of the protocol. The long-term nature of the protocol enabled assessment of bone parameters similar to those observed in AN patients. Both restricted groups adapted their energy metabolism differentially in the short and long term, with less fat oxidation in FRW mice and a preferential use of glucose to compensate for the chronic energy imbalance. Finally, like restrictive AN patients, FRW mice exhibited low leptin levels, high plasma concentrations of corticosterone and ghrelin, and a disruption of the estrous cycle. In conclusion, our model suggests that physical activity has beneficial effects on the adaptation to the severe condition of food restriction despite the absence of any protective effect on lean and bone mass.

Sociocultural risk factors for compulsive exercise: a prospective study of adolescents

The risk factors for compulsive exercise are unknown. This study aims to explore longitudinal sociocultural risk factors for compulsive exercise, using a 12-month prospective design. A sample of 332 male and female adolescents (aged 13-15 years at baseline) completed self-report measures of sociocultural risk factors and compulsive exercise at baseline and eating disorder psychopathology and compulsive exercise at 12-month follow-up assessment. Hierarchical regressions found that family and peer messages to become more muscular predicted compulsive exercise in boys, whereas feeling pressure from the media to be thin was a significant predictor of compulsive exercise in girls. These relationships remained significant when controlling for eating disorder psychopathology but became nonsignificant when initial levels of compulsive exercise were entered into the model. The findings suggest that sociocultural risk factors may contribute to the development of compulsive exercise but future research should utilise a younger sample and employ a longer follow-up period to identify true longitudinal effects.

Serotonergic pharmacology in animal models: from behavioral disorders to dyskinesia

Serotonin (5-HT) dysfunction has been involved in both movement and behavioral disorders. Serotonin pharmacology improves dyskinetic movements as well as depressive, anxious, aggressive and anorexic symptoms. Animal models have been useful to investigate more precisely to what extent 5-HT is involved and whether drugs targeting the 5-HT system can counteract the symptoms exhibited. We review existing rodent and non-human primate (NHP) animal models in which selective 5-HT or dual 5-HT-norepinephrine (NE) transporter inhibitors, as well as specific 5-HT receptors agonists and antagonists, monoamine oxidase A inhibitors (IMAO-A) and MDMA (Ecstasy) have been used. We review overlaps between the various drug classes involved. We confront behavioral paradigms and treatment regimen. Some but not all animal models and associated pharmacological treatments have been extensively studied in the litterature. In particular, the impact of selective serotonin reuptake inhibitors (SSRI) has been extensively investigated using a variety of pharmacological or genetic rodent models of depression, anxiety, aggressiveness. But the validity of these rodent models is questioned. On the contrary, few studies did address the potential impact of targeting the 5-HT system on NHP models of behavioral disorders, despite the fact that those models may match more closely to human pathologies. Further investigations with carefull behavioral analysis will improve our understanding of neural bases underlying the pathophysiology of movement and behavioral disorders.

Uncontrollable behavior or mental illness? Exploring constructions of bulimia using Q methodology

BACKGROUND

In medical and psychological literature bulimia is commonly described as a mental illness. However, from a social constructionist perspective the meaning of bulimia will always be socially and historically situated and multiple. Thus, there is always the possibility for other understandings or constructions of bulimia to circulate in our culture, with each having distinct real-world implications for those engaging in bulimic behaviors; for instance, they might potentially influence likelihood of help-seeking and the success of treatment. This study used Q methodology to explore culturally-available constructions of bulimia nervosa.

METHODS

Seventy-seven adults with varying experience of eating disorders took part in this Q methodological study. Online, they were asked to rank-order 42 statements about bulimia, and then answer a series of questions about the task and their knowledge of bulimia. A by-person factor analysis was then conducted, with factors extracted using the centroid technique and a varimax rotation.

RESULTS

Six factors satisfied selection criteria and were subsequently interpreted. Factor A, "bulimia as uncontrolled behavior", positions bulimia as a behavioral rather than psychological issue. Factor B, entitled "bulimia is a distressing mental illness", reflects an understanding of bulimic behaviors as a dysfunctional coping mechanism, which is often found in psychological literature. Other perspectives position bulimia as about "self-medicating with food" (Factor C), "the pathological pursuit of thinness" (Factor D), "being the best at being thin" (Factor E), or as "extreme behavior vs. mentally ill" (Factor F). These constructions have distinct implications for the subjective experience and behavior of those engaged in bulimic behaviors, with some constructions possibly being more useful in terms of help-seeking (Factor B), while others position these individuals in ways that may be distressing, for instance as shallow (Factor D) or to blame (Factor E).

CONCLUSIONS

This study has identified a range of distinct constructions of bulimia. These constructions are considered to have implications for the behaviors and experiences of those engaging in bulimic behaviors. As such, further research into constructions of bulimia may illuminate factors that influence help-seeking and the self-perceptions of such individuals.

Impaired inhibitory control in anorexia nervosa elicited by physical activity stimuli

Besides food restriction, hyperactivity is considered a key behavioral trait of anorexia nervosa (AN), playing a major role in the pathogenesis and progression of the disorder. However, the underlying neurophysiology remains poorly understood. We used functional magnetic resonance imaging during two affective go/no-go tasks to probe inhibitory control in response to stimuli depicting physical activity vs inactivity and food vs non-food in AN patients compared with 26 healthy athlete and non-athlete controls. We hypothesized that neural correlates of behavioral inhibition are biased by the emotional information of the stimuli in AN patients, leading to a differential neural inhibitory pattern during the two tasks. Indeed, we found reduced response inhibition for food and non-food images in the putamen, while stimuli depicting physical activity resulted in an exaggerated response of the prefrontal cortex (PFC) and cerebellum in AN patients. However, both AN patients and athletes revealed an increased response in the somatosensory cortex to physical activity stimuli. These results suggest that physical activity stimuli might place an increased demand on the inhibitory control system in AN patients. The resulting hyperactivity of the PFC and cerebellum may lead to altered executive function and motor control, sustaining increased physical activity in AN patients.

The relationship between obsessive-compulsive personality disorder traits, obsessive-compulsive disorder and excessive exercise in patients with anorexia nervosa: a systematic review

OBJECTIVE

Obsessive-compulsive personality disorder (OCPD) traits and obsessive-compulsive disorder (OCD) are commonly associated with patients with Anorexia Nervosa (AN). The aim of this review was to systematically search the literature to examine whether OCPD and OCD are positively associated with excessive exercise in patients with AN.

METHOD

A systematic electronic search of the literature (using PsycInfo, Medline and Web of Knowledge) was undertaken to identify relevant publications until May 2012.

RESULTS

A total of ten studies met criteria for inclusion in the review. The design of the studies varied from cross-sectional to retrospective and quasi-experimental. Seven out of the ten studies reviewed demonstrated a positive relationship between OCPD and/or OCD in AN patients who exercise excessively, whilst three studies found a lack of relationship, or a negative relationship, between these constructs.

CONCLUSION

There is evidence from the literature to suggest that there is a positive relationship between OCPD and excessive exercise in patients with AN. However, the relationship between OCD and excessive exercise is less clear and further research is required to qualify the strength of such relationships. Future research should utilise the most comprehensive and reliable clinical assessment tools, and address prognostic factors, treatment factors and specific interventions for patients with OCPD and/or OCD and excessive exercise.

Beliefs about exercise: relationship to eating psychopathology and core beliefs among young female exercisers

OBJECTIVE

This study had two objectives. First, to determine links between levels of eating psychopathology and beliefs about exercise among young women. Second, to determine the predictive effects of unhealthy core beliefs on exercise beliefs.

METHOD

A convenience sample of 185 young female exercisers completed the Eating Disorders Inventory (EDI), the Exercise Beliefs Questionnaire (EBQ) and the Young Schema Questionnaire (YSQ).

RESULTS

The participants' mean scores on the EDI were as follows: drive for thinness=0.69 (SD=0.82); body dissatisfaction=1.30 (SD=0.86); and bulimia=0.33 (SD=0.42). There were significant, positive correlations of all three EDI scales with EBQ social and EBQ appearance subscales. In addition, YSQ Defectiveness/Shame beliefs predicted EBQ social scores, while YSQ Unrelenting Standards predicted EBQ appearance scores.

DISCUSSION

Those women with relatively unhealthy eating attitudes are likely to believe that exercise will prevent negative social consequences, and are likely to be motivated to exercise in order to preserve or enhance their physical appearance. These same types of exercise belief (regarding social consequences and appearance) are predicted by feelings of defectiveness and shame and by unrelenting high personal standards.

The nucleus accumbens 5-HTR₄-CART pathway ties anorexia to hyperactivity

In mental diseases, the brain does not systematically adjust motor activity to feeding. Probably, the most outlined example is the association between hyperactivity and anorexia in Anorexia nervosa. The neural underpinnings of this 'paradox', however, are poorly elucidated. Although anorexia and hyperactivity prevail over self-preservation, both symptoms rarely exist independently, suggesting commonalities in neural pathways, most likely in the reward system. We previously discovered an addictive molecular facet of anorexia, involving production, in the nucleus accumbens (NAc), of the same transcripts stimulated in response to cocaine and amphetamine (CART) upon stimulation of the 5-HT(4) receptors (5-HTR(4)) or MDMA (ecstasy). Here, we tested whether this pathway predisposes not only to anorexia but also to hyperactivity. Following food restriction, mice are expected to overeat. However, selecting hyperactive and addiction-related animal models, we observed that mice lacking 5-HTR(1B) self-imposed food restriction after deprivation and still displayed anorexia and hyperactivity after ecstasy. Decryption of the mechanisms showed a gain-of-function of 5-HTR(4) in the absence of 5-HTR(1B), associated with CART surplus in the NAc and not in other brain areas. NAc-5-HTR(4) overexpression upregulated NAc-CART, provoked anorexia and hyperactivity. NAc-5-HTR(4) knockdown or blockade reduced ecstasy-induced hyperactivity. Finally, NAc-CART knockdown suppressed hyperactivity upon stimulation of the NAc-5-HTR(4). Additionally, inactivating NAc-5-HTR(4) suppressed ecstasy's preference, strengthening the rewarding facet of anorexia. In conclusion, the NAc-5-HTR(4)/CART pathway establishes a 'tight-junction' between anorexia and hyperactivity, suggesting the existence of a primary functional unit susceptible to limit overeating associated with resting following homeostasis rules.

Hyperactivity in anorexia nervosa: warming up not just burning-off calories

Excessive physical activity is a common feature in Anorexia Nervosa (AN) that interferes with the recovery process. Animal models have demonstrated that ambient temperature modulates physical activity in semi-starved animals. The aim of the present study was to assess the effect of ambient temperature on physical activity in AN patients in the acute phase of the illness. Thirty-seven patients with AN wore an accelerometer to measure physical activity within the first week of contacting a specialized eating disorder center. Standardized measures of anxiety, depression and eating disorder psychopathology were assessed. Corresponding daily values for ambient temperature were obtained from local meteorological stations. Ambient temperature was negatively correlated with physical activity (p = −.405) and was the only variable that accounted for a significant portion of the variance in physical activity (p = .034). Consistent with recent research with an analogous animal model of the disorder, our findings suggest that ambient temperature is a critical factor contributing to the expression of excessive physical activity levels in AN. Keeping patients warm may prove to be a beneficial treatment option for this symptom.

Neurobiology driving hyperactivity in activity-based anorexia

Hyperactivity in anorexia nervosa is difficult to control and negatively impacts outcome. Hyperactivity is a key driving force to starvation in an animal model named activity-based anorexia (ABA). Recent research has started unraveling what mechanisms underlie this hyperactivity. Besides a general increase in locomotor activity that may be an expression of foraging behavior and involves frontal brain regions, the increased locomotor activity expressed before food is presented (food anticipatory behavior or FAA) involves hypothalamic neural circuits. Ghrelin plays a role in FAA, whereas decreased leptin signaling is involved in both aspects of increased locomotor activity. We hypothesize that increased ghrelin and decreased leptin signaling drive the activity of dopamine neurons in the ventral tegmental area. In anorexia nervosa patients, this altered activity of the dopamine system may be involved not only in hyperactivity but also in aberrant cognitive processing related to food.

Reward processing in anorexia nervosa

Individuals with anorexia nervosa (AN) demonstrate a relentless engagement in behaviors aimed to reduce their weight, which leads to severe underweight status, and occasionally death. Neurobiological abnormalities, as a consequence of starvation are controversial: evidence, however, demonstrates abnormalities in the reward system of patients, and recovered individuals. Despite this, a unifying explanation for reward abnormalities observed in AN and their relevance to symptoms of the illness, remains incompletely understood. Theories explaining reward dysfunction have conventionally focused on anhedonia, describing that patients have an impaired ability to experience reward or pleasure. We review taste reward literature and propose that patients' reduced responses to conventional taste-reward tasks may reflect a fear of weight gain associated with the caloric nature of the tasks, rather than an impaired ability to experience reward. Consistent with this, we propose that patients are capable of 'liking' hedonic taste stimuli (e.g., identifying them), however, they do not 'want' or feel motivated for the stimuli in the same way that healthy controls report. Recent brain imaging data on more complex reward processing tasks provide insights into fronto-striatal neural circuit dysfunction related to altered reward processing in AN that challenges the relevance of anhedonia in explaining reward dysfunction in AN. In this way, altered activity of the anterior cingulate cortex and striatum could explain patients' pathological engagement in behaviors they consider rewarding (e.g., self-starvation) that are otherwise aversive or punishing, to those without the eating disorder. Such evidence for altered patterns of brain activity associated with reward processing tasks in patients and recovered individuals may provide important information about mechanisms underlying symptoms of AN, their future investigation, and the development of treatment approaches.

Psychometric evaluation of the compulsive exercise test (CET) in an adolescent population: links with eating psychopathology

OBJECTIVE

Compulsive exercise describes a rigid, driven urge to exercise that has been reported in different populations, including eating disorder patients. This compulsion can develop at an early age and yet the measurement of compulsive exercise in adolescents is limited by inappropriate assessment techniques. This study aimed to psychometrically evaluate the Compulsive Exercise Test (CET) in a sample of adolescents.

METHODS

The sample consisted of 1012 adolescents aged 12-14 years old, who completed the CET, the Commitment to Exercise Scale (CES), and selected subscales from the Eating Disorder Inventory-2 (EDI-2).

RESULTS

Results confirmed the original five-factor solution of the CET. The CET's concurrent validity with the CES, as well as the convergent validity with the EDI-2, was established. The CET was not strongly related to exercise frequency.

CONCLUSION

The CET appears to be valid and reliable for use with adolescents. Replication with an adolescent clinical eating disorder sample is now required.

Disordered eating and exercise: development and preliminary validation of the compulsive exercise test (CET)

OBJECTIVE

The Compulsive Exercise Test (CET) was developed to assess the primary factors operating in the maintenance of excessive exercise.

METHODS

A total of 367 young female exercisers were recruited from University campuses. Across three separate studies, the participants completed either the CET alone, or the CET and other standard self-report measures of excessive exercise and eating psychopathology.

RESULTS

Factor analyses yielded five factors from which a final 24-item, five subscale measure was constructed. The CET demonstrated high internal consistency across the three samples. Supporting the concurrent and convergent validity of the scale, the CET correlated in the expected direction with existing measures of excessive exercise and eating pathology. As expected, the CET explained greater variance in eating pathology than existing measures of excessive exercise.

DISCUSSION

The resulting subscales of the CET are consistent with a cognitive-behavioural maintenance model of excessive exercise and support the multidimensionality of the excessive exercise construct. Further research is required to validate the instrument within a sample of eating disordered women.

Compulsive exercise and eating disorders

The aim of this review was to develop an empirically supported cognitive behavioural model of compulsive exercise within the context of the eating disorders. A systematic review of the correlates and predictors of compulsive exercise among eating disordered patients identified four key correlates. These were subsequently validated by a second review, incorporating both the clinical and non-clinical as well as the exercise science literatures. A proposed model is presented which is both evidence-based and testable.

The cannabinoid receptor agonist THC attenuates weight loss in a rodent model of activity-based anorexia

Anorexia nervosa (AN) is characterized by anhedonia whereby patients experience little pleasure or reward in many aspects of their lives. Reward pathways and the endocannabionid system have been implicated in the mediation of food intake. The potential to exploit these systems to reverse weight loss is investigated in a rodent model of activity-based anorexia (ABA). The effect of subchronic (6 days) Δ(9)-tetrahydrocannabinol (THC) treatment (0.1, 0.5, or 2.0 mg/kg/day) was assessed on chow and high-fat diet (HFD) intake, body weight, running wheel activity (RWA) as well as thermogenesis in brown adipose tissue (BAT) and lipid metabolism in white adipose tissue (WAT). Limited time availability of food and continuous access to running wheels led to anorexia and significantly reduced body weight. THC treatment (0.5 and 2.0 mg/kg/day) transiently stimulated chow intake with a moderate effect on RWA. THC (2.0 mg/kg/day) significantly reduced body weight loss and shifted markers of thermogenesis in BAT and lipid metabolism in WAT in directions consistent with reduced energy expenditure and lipolysis. THC (2.0 mg/kg/day) combined with HFD, produced a transient increase in food intake, reduction in RWA, attenuation of body weight loss, and changes in markers of thermogensis in BAT and lipolysis in the WAT. These changes were significantly greater than those seen in vehicle (HFD), vehicle (chow), and THC (chow)-treated animals. These data show for the first time the effectiveness of the endocannabinoid system in attenuating the weight loss associated with the development of ABA via a mechanism involving reduced energy expenditure.

Oestrogen: an overlooked mediator in the neuropsychopharmacology of treatment response?

Major depression (MD) and anorexia nervosa (AN) often present comorbidly and both share some affective symptoms, despite obvious phenotypic differences. In the illness phase, pathophysiological evidence indicates similar abnormalities in both clinical groups including dysfunction in the serotonin (5-HT) system (of which some abnormalities persist following recovery) and between 60% and 80% of patients in both groups present with significant hyperactivity of the hypothalamo-pituitary-adrenal (HPA) axis. First-line approach to treatment for MD involves modulation of the 5-HT system using selective serotonin reuptake inhibitors (SSRIs). For AN, treatment with SSRIs has been shown to be considerably less effective compared to MD. Both illnesses show marked dysregulation in the HPA axis. A consequence of SSRI treatment is a reduction and/or normalization of indices of the HPA axis [i.e. cortisol, adrenocorticotropic hormone (ACTH)], which is consistent with recovery levels in both clinical groups. Oestrogen (in high doses) has been shown to exert antidepressant effects and positively impact on MD symptoms as a treatment in its own right, or in combination with antidepressants, in women of menopausal age. It is proposed that a combination of SSRIs and oestrogen therapy may facilitate physiological normalization in MD in women of non-menopausal age and in AN. Preliminary evidence suggests oestrogen treatment alone is of some benefit to patients and it is proposed that a combination of SSRI and oestrogen will precipitate and potentially accelerate symptomatic remission. Should this approach be successful, it offers the capacity for improvement over traditional antidepressant use in women diagnosed with MD and a novel strategy for the treatment of AN, a serious clinical illness associated with the highest mortality of any psychiatric condition.

Sex differences precipitating anorexia nervosa in females: the estrogen paradox and a novel framework for targeting sex-specific neurocircuits and behavior

In anorexia nervosa (AN), reward contamination likely plays a significant role in maintenance of the illness. Reward contamination is a context in which patients' behaviors of self-starvation and excessive exercise, while initially rewarding, become aversive, even punishing; but patients may not recognize the punishing and conflicted/contaminated behaviors. An emerging neurocircuit encompassing the anterior cingulate cortex (ACC) has been functionally linked to symptoms including reward contamination and body dysmorphic processing. Owing to the significantly greater prevalence of AN in females, evidence from clinical literature and preclinical models is spearheaded to provide a novel rationale for estrogen triggering sensitivity to the experience of stress and reward, precipitating AN disproportionately in females at the time of puberty. Paradoxically, however, estrogen may facilitate response to pharmacological interventions and (desensitization of the identified neurocircuits) via its contribution to serotonin modulation, hypothalamo-pituitary adrenal (HPA)-axis attenuation, and effects on dopamine.

Experience with activity based anorexia enhances conditioned taste aversion learning in rats

Activity based anorexia (ABA) is a model that mimics the self-starvation and hyperactivity features of anorexia nervosa (AN). This study investigated whether a history of ABA will enhance food avoidance learning and retard its extinction in female rats. We compared the acquisition and extinction of a conditioned taste aversion (CTA) in naive (ad lib with no access to RW), ABA, and pair-fed to the food intake of ABA (with access to a locked RW) female Sprague-Dawley rats. The CTA conditioning was conducted after the ABA and pair-fed rats had recovered to their pre-food restriction body weights. For the CTA learning, 0.3M sucrose consumption was followed by low doses LiCl (0.009M or 0.018M at 1.33ml/100g of body weight, IP) injection. The results revealed that the ABA rats acquired an aversion to sucrose significantly sooner than the naive controls. Furthermore, they completely avoided sucrose while the naive and pair-fed controls still sampled it by the end of 10 conditioning trials. When extinction was assessed by 1-bottle and 2-bottle tests, the ABA rats extinguished more slowly than the controls. However, the differences in sucrose aversion extinction between the ABA and control rats were only significant in the 1-bottle test. These data suggest that experience with AN-like behaviors results in an acquired aversion to a preferred food sooner and a longer retention of the negative food associations. These findings have implications for understanding the persistence of aberrant eating behaviors in eating disorders.