Exercise "addiction" in anorexia nervosa: model development and pilot data

The Fitter I Am, the Larger I Feel-The Vicious Circle of Physical Exercise in Anorexia Nervosa

Introduction: Body image distortion is a core symptom of anorexia nervosa (AN), embodying dissatisfaction and overvaluation of body appearance and weight. Body image distortion is an important factor in the maintenance of weight loss behaviours such as compulsive physical exercise. Conversely, physical exercise seems to have an aggravating effect on body image in patients with AN, but the evidence is still poor. The aim of this study was to examine the relationship between body image distortion and physical exercise in AN in order to understand whether physical exercise may play a specific role in body image distortion beyond psychopathological severity. Methods: Forty patients with AN and 21 healthy controls were tested for body image distortion and different proxies of physical exercise. Univariate correlations tested the relationship between body image distortion and physical exercise in AN and control groups. Then, to experimentally assess the effect of exercise on body image distortion, participants were invited to rate their body image before and after a standardised effort test. Results: In the AN group, a correlation was found between physical activity and body image distortion (p < 0.01), which was still significant after controlling for psychopathological severity. No correlation was found in healthy controls. After a standardised effort, patients with AN had higher increases in body image distortion than healthy controls (almost 4 kg/m2 vs. 0.8 kg/m2) (p < 0.01). Discussion: Physical exercise may contribute to the distortion of body image in anorexia nervosa and explain the paradoxical augmentation of unhealthy exercise despite ongoing weight loss.

Morphing analysis of facial emotion recognition in anorexia nervosa: association with physical activity

PURPOSE

Anorexia Nervosa (AN) has been linked to emotion processing inefficiencies, social cognition difficulties and emotion dysregulation, but data on Facial Emotion Recognition (FER) are heterogenous and inconclusive. This study aims to explore FER in patients with AN using a dynamic and ecological evaluation, and its relationship with Physical Activity (PA), an important aspect of AN that could impact emotional processing.

METHODS

Sixty-six participants (33 patients with AN and 33 healthy controls) performed a morphed facial emotional recognition task and 49 of them wore an accelerometer during seven days to assess PA. Axis-I disorders and depressive symptoms have been assessed.

RESULTS

No difference was found regarding time to recognize facial emotions. However, patients with AN correctly recognize emotions more frequently than controls. This was specific to disgust, although there was also a tendency for sadness. Among patients, higher depressive scores are associated with a faster and more accurate recognition of disgust, while a higher level of PA is associated to decreased accuracy in recognizing sadness.

CONCLUSION

Patients with AN are capable of recognizing facial emotions as accurately as controls, but could have a higher sensitivity in recognizing negative emotions, especially disgust and sadness. PA has opposite effects and, thus, could be considered as an emotional regulation strategy against negative affect.

LEVEL OF EVIDENCE II

Controlled trial without randomization.

A Review of the Components of Problematic Exercise in Psychometric Assessment Instruments

Backgrounds

The range of theoretical conceptualizations of problematic exercise in psychometric assessment instruments makes it difficult to identify the components that define this phenomenon. A better understanding of the underlying components of problematic exercise may contribute to progress toward providing scientific evidence that allows for deciding whether problematic exercise should be considered a substantive mental health disorder. The objective of the present review was to examine and compare, through a content analysis of their items, the components of problematic exercise in psychometric assessment instruments identified in a recent systematic review.

Methods

A total of 33 components of problematic exercise were identified in the 17 assessment instruments included in the present review.

Results

The results show that, despite the lack of consensus in the operational definition of their factors and the variety of ways of wording their items, the instruments reflect some common components that might indicate core criteria (i.e., salience, withdrawal, and mood modification) or candidate components (i.e., conflict, and continuance despite problems) of problematic exercise. However, other components of different nature were shown to be specific to some of the problematic exercise conceptualizations on which the assessment instruments are based.

Conclusion

In the interest of reaching a consensus that allows to advance in this research field, further studies are needed to resolve which components are inherently problematic.

The Relationship between Alexithymia, Dysmorphic Concern, and Exercise Addiction: The Moderating Effect of Self-Esteem

As with other addictions, exercise addiction can severely impact individuals' lives and have significant psychophysical consequences. Consequently, the study of the mechanisms involved in this psychopathological condition has great clinical and practical relevance. Therefore, the goal of the present study was to explore the risk factors and protective factors for exercise addiction, with a particular focus on the roles of alexithymia, body image concerns, and self-esteem. A sample of 288 regular exercisers (mean age = 28.35 years, SD = 8.26; 72% females, 18% males) completed the Exercise Addiction Inventory, 20-Item Toronto Alexithymia Scale, Body Image Concern Inventory, and Rosenberg Self-Esteem Scale. Data were analyzed by implementing a moderated mediation model. Results showed a significant and positive association between alexithymia and exercise addiction, totally mediated by body image concerns. Furthermore, self-esteem showed a relevant moderating effect, such that at high levels of self-esteem the effect of alexithymia on body image concerns became insignificant. Such data have important implications, highlighting some core variables on which it might be useful to keep a focus in order to elaborate tailored interventions, from both preventive and treatment perspectives.

Protective and Risk Factors in Exercise Addiction: A Series of Moderated Mediation Analyses

For a minority of individuals, exercise may become excessive and lead to an addictive behaviour. To better understand the processes by which exercise could become an addiction, the present study examined the risk and protective factors of exercise addiction among regular exercisers, by investigating the role of drive for thinness, bulimia, body dissatisfaction, body image concerns, and self-esteem. A sample of 319 Italian regular exercisers (M_age = 30.78 years, SD = 11.98) completed the Italian versions of the Exercise Addiction Inventory, Eating Disorder Inventory-3 Referral Form, Body Image Concern Inventory, and Rosenberg Self-Esteem Scale. Data were analyzed by implementing a series of moderated mediations. Drive for thinness, bulimia, and body dissatisfaction were positively associated with exercise addiction. An indirect path was found in each of these relationships, which included the mediation of body image concerns, as well as a significant moderation of self-esteem in the associations between drive for thinness, bulimia, body dissatisfaction, and the mediator. High self-esteem appeared to be a protective factor. The higher the level of self-esteem, the less indirect the effects of thinness drive, bulimia, body dissatisfaction, and body image concerns were on exercise addiction. Such findings contribute to a better understanding concerning the risk and protective factors of excessive exercise, and may have important practical implications in structuring interventions to reduce risk of developing exercise addiction, as well as orienting future research.

Physical exercise-related endophenotypes in anorexia nervosa

BACKGROUND

The persistence of physical exercise in anorexia nervosa (AN) despite underweight and its maintaining factors are poorly understood. The aim of this study was to explore the attitudes toward physical exercise and its effects on emotions, cognitive functioning, and body image perception in patients with AN, and to search for exercise-related endophenotypes of the pathology.

METHODS

Physical exercise dependence, quantity, and dysregulation were assessed by the Exercise Dependence Scale (EDS), the Godin Leisure Time Exercise Questionnaire (GLTEQ) and a standardized effort test in 88 patients with AN, 30 unaffected relatives and 89 healthy controls. Changes in positive and negative affect, cognitive rigidity, and body image distortion were measured before and after the effort test in the three groups.

RESULTS

Patients with AN had higher scores on the EDS and the GLTEQ and used more effort in the standardized effort test. These three measures of physical exercise correlated with negative emotions at baseline. After the effort test, patients with AN had marked emotional improvement, a moderate increase in body image distortion and a small increase in cognitive rigidity compared to HC. Unaffected relatives also had a significant postexercise increase of positive emotion.

DISCUSSION

The mood-related drive for physical exercise has the characteristics of an endophenotype of the disorder. Excessive and driven physical exercise may be state-associated features of AN, driven by the positive effect on emotional wellbeing.

Theoretical conceptualisations of problematic exercise in psychometric assessment instruments: A systematic review

BACKGROUND AND AIMS

The aim of the present systematic review was to identify psychometric tools developed to assess problematic exercise in order to identify and compare their theoretical conceptualisations on which they are based.

METHODS

A systematic literature search was conducted in the electronic databases Web of Science, Scielo, PsychINFO, PsycTEST and SCOPUS from their inception to January 2020.

RESULTS

Seventeen assessment instruments met the eligibility criteria to be included in the present review. The instruments were classified according to their conceptualisation into five groups: (i) problematic exercise as an end of an exercise continuum, (ii) problematic exercise as a means of regulating body size and weight, (iii) problematic exercise as dependence, (iv) problematic exercise as a behavioural addiction and (v) no clear conceptualisation.

DISCUSSION

The results suggest that the conceptualisations of the assessment instruments have resulted in a strong dichotomy in relation to the primary or secondary character of the problematic exercise that might be limiting the capacity of the instruments to adequately capture the multidimensionality of this construct.

CONCLUSIONS

Given the interest in understanding the complexity surrounding the problematic exercise, future research should develop more comprehensive definitions of this construct. This would allow a greater conceptual consensus to be reached that would allow progress to be made in the study of the problematic exercise.

A comparative meta-analysis of the prevalence of exercise addiction in adults with and without indicated eating disorders

BACKGROUND

Exercise addiction is associated with multiple adverse outcomes and can be classified as co-occurring with an eating disorder, or a primary condition with no indication of eating disorders. We conducted a meta-analysis exploring the prevalence of exercise addiction in adults with and without indicated eating disorders.

METHODS

A systematic review of major databases and grey literature was undertaken from inception to 30/04/2019. Studies reporting prevalence of exercise addiction with and without indicated eating disorders in adults were identified. A random effect meta-analysis was undertaken, calculating odds ratios for exercise addiction with versus without indicated eating disorders.

RESULTS

Nine studies with a total sample of 2140 participants (mean age = 25.06; 70.6% female) were included. Within these, 1732 participants did not show indicated eating disorders (mean age = 26.4; 63.0% female) and 408 had indicated eating disorders (mean age = 23.46; 79.2% female). The odds ratio for exercise addiction in populations with versus without indicated eating disorders was 3.71 (95% CI 2.00-6.89; I² = 81; p  ≤ 0.001). Exercise addiction prevalence in both populations differed according to the measurement instrument used.

DISCUSSION

Exercise addiction occurs more than three and a half times as often as a comorbidity to an eating disorder than in people without an indicated eating disorder. The creation of a measurement tool able to identify exercise addiction risk in both populations would benefit researchers and practitioners by easily classifying samples.

Prevalence and Correlates of Exercise Addiction in the Presence vs. Absence of Indicated Eating Disorders

Despite the many benefits of regular, sustained exercise, there is evidence that exercise can become addictive, to the point where the exerciser experiences negative physiological and psychological symptoms, including withdrawal symptoms upon cessation, training through injury, and the detriment of social relationships. Furthermore, recent evidence suggests that the etiology of exercise addiction is different depending on the presence or absence of eating disorders. The aim of this study was to explore to what extent eating disorder status, body dysmorphic disorder, reasons for exercise, social media use, and fitness instructor status were associated with exercise addiction, and to determine differences according to eating disorder status. The key findings showed that the etiology of exercise addiction differed according to eating disorder status, with variables including social media use, exercise motivation, and ethnicity being uniquely correlated with exercise addiction only in populations with indicated eating disorders. Furthermore, body dysmorphic disorder was highly prevalent in subjects without indicated eating disorders, and could be a primary condition in which exercise addiction is a symptom. It is recommended that clinicians and practitioners working with patients who present with symptoms of exercise addiction should be screened for eating disorders and body dysmorphic disorder before treatments are considered.

The relationship between moderate to vigorous physical activity and cognitive rigidity in anorexia nervosa

A drive for physical activity despite underweight is a core feature of anorexia nervosa. This pilot study detects which aspect of physical activity, if any, could be related to cognitive rigidity in anorexia nervosa. Twenty-eight outpatients with anorexia nervosa and 24 healthy participants were assessed for cognitive flexibility with the Trail Making Test (TMT) and for multiple dimensions of physical activity by subjective and objective assessments. Correlation analysis was conducted to disentangle the relationship between cognitive rigidity and the different aspects of physical activity, then, the moderating effect of anorexia nervosa on this relationship was assessed. A principal component analysis was performed to incorporate all variables of physical activity in (a) global factor(s) reflecting the multidimensional nature of this construct. Cognitive rigidity (TMT b - a score) was significantly correlated to the amount of objectively assessed physical activity estimated, only in the sample of patients with anorexia nervosa. The principal component analysis confirms the correlation between a single construct of "physical activity" and cognitive rigidity in anorexia nervosa only. This pilot study suggests a relationship between cognitive rigidity and physical activity that could help explain the persistence of the latter despite ongoing malnutrition in patients with anorexia nervosa.

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.

Testing an emotion regulation model of physical activity in adolescents with anorexia nervosa: A pilot ecological momentary assessment

OBJECTIVE

Adolescents with anorexia nervosa (AN) often show increased levels of exercise and physical activity. Psychological models suggest that physical activity in AN might attenuate momentary negative affect. However, this has not been directly tested in adolescents with AN, and it remains unclear whether this is a distinct mechanism of physical activity in AN compared with healthy controls (HCs).

METHOD

In a 1-day ecological momentary assessment, 32 adolescent inpatients with AN and 30 HCs responded to hourly questions on momentary affect while wearing an actigraph to objectively assess physical activity.

RESULTS

Linear mixed models identified that adolescents with AN experienced more aversive tension, more negative affect, and less positive affect throughout the day than HCs. Preliminary evidence for a momentary association of higher levels of physical activity with positive affect were found for both groups, whereas higher levels of physical activity were associated with less negative affect in adolescents with AN only. When correcting for multiple testing, interactions did not hold statistical significance.

DISCUSSION

Our results indicate a down-regulation effect of physical activity on negative affect for AN and a more general up-regulation effect of positive affect. However, our sample size was small, and replication of our findings is needed.

Impaired brain endocannabinoid tone in the activity-based model of anorexia nervosa

OBJECTIVE

Despite the growing knowledge on the functional relationship between an altered endocannabinoid (eCB) system and development of anorexia nervosa (AN), to date no studies have investigated the central eCB tone in the activity-based anorexia (ABA) model that reproduces key aspects of human AN.

METHOD

We measured levels of two major eCBs, anandamide (AEA) and 2-arachidonoylglycerol (2-AG), those of two eCB-related lipids, oleoylethanolamide (OEA) and palmitoylethanolamide (PEA), and the cannabinoid type-1 receptor (CB1R) density in the brain of female ABA rats, focusing on areas involved in homeostatic and rewarding-related regulation of feeding behavior (i.e., prefrontal cortex, nucleus accumbens, caudato putamen, amygdala, hippocampus and hypothalamus). Analysis was carried out also at the end of recovery from the ABA condition.

RESULTS

At the end of the ABA induction phase, 2-AG was significantly decreased in ABA rats in different brain areas but not in the caudato putamen. No changes were detected in AEA levels in any region, whereas the levels of OEA and PEA were decreased exclusively in the hippocampus and hypothalamus. Furthermore, CB1R density was decreased in the dentate gyrus of hippocampus and in the lateral hypothalamus. After recovery, both 2-AG levels and CB1R density were partially normalized in some areas. In contrast, AEA levels became markedly reduced in all the analyzed areas.

DISCUSSION

These data demonstrate an altered brain eCB tone in ABA rats, further supporting the involvement of an impaired eCB system in AN pathophysiology that may contribute to the maintenance of some symptomatic aspects of the disease.

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.

Bilateral Simultaneous Femoral Neck Stress Fracture Despite Clinical Recovery from Anorexia Nervosa: A Case Report

CASE

A 38-year-old woman who had returned to sports activity (running) after having clinically recovered from anorexia nervosa presented with a bilateral femoral neck stress fracture that was treated with bilateral hip osteosynthesis.

CONCLUSION

Although exercise is usually considered to be beneficial for health, heavy exercise (such as running) after recovery from anorexia nervosa may be associated with an increased risk of fracture.

Frequent exercise: A healthy habit or a behavioral addiction?

It is well known that regular physical activity helps improve overall health and fitness and reduces the risk of many chronic diseases. However, excessive exercise might be harmful. Exercise addiction (EA) is a pattern of uncontrolled exercise that involves a craving for overwhelming exercise with addictive attributes. So far, little is known about this unique behavioral addiction. The aim of the current study is to introduce the diagnosis and assessment of EA, and to summarize several developing theoretical models. Eating disorders, body image disorder, low self-esteem, and high narcissism are related to high risk of EA. The paper also discusses the distinction between EA and highly involved physical activity.

Activity-Based Anorexia Alters the Expression of BDNF Transcripts in the Mesocorticolimbic Reward Circuit

Anorexia nervosa (AN) is a complex eating disorder with severe dysregulation of appetitive behavior. The activity-based anorexia (ABA) paradigm is an animal model in which rodents exposed to both running wheels and scheduled feeding develop aspects of AN including paradoxical hypophagia, dramatic weight loss, and hyperactivity, while animals exposed to only one condition maintain normal body weight. Brain-derived neurotrophic factor (BDNF), an activity-dependent modulator of neuronal plasticity, is reduced in the serum of AN patients, and is a known regulator of feeding and weight maintenance. We assessed the effects of scheduled feeding, running wheel access, or both on the expression of BDNF transcripts within the mesocorticolimbic pathway. We also assessed the expression of neuronal cell adhesion molecule 1 (NCAM1) to explore the specificity of effects on BDNF within the mesocorticolimbic pathway. Scheduled feeding increased the levels of both transcripts in the hippocampus (HPC), increased NCAM1 mRNA expression in the ventral tegmental area (VTA), and decreased BDNF mRNA levels in the medial prefrontal cortex (mPFC). In addition, wheel running increased BDNF mRNA expression in the VTA. No changes in either transcript were observed in the nucleus accumbens (NAc). Furthermore, no changes in either transcript were induced by the combined scheduled feeding and wheel access condition. These data indicate that scheduled feeding or wheel running alter BDNF and NCAM1 expression levels in specific regions of the mesocorticolimbic pathway. These findings contribute to our current knowledge of the molecular alterations induced by ABA and may help elucidate possible mechanisms of AN pathology.

Maladaptive perfectionism as mediator among psychological control, eating disorders, and exercise dependence symptoms in habitual exerciser

Background and aims The current study examined the mediating role of maladaptive perfectionism among parental psychological control, eating disorder symptoms, and exercise dependence symptoms by gender in habitual exercisers. Methods Participants were 348 Italian exercisers (n = 178 men and n = 170 women; M age = 20.57, SD = 1.13) who completed self-report questionnaires assessing their parental psychological control, maladaptive perfectionism, eating disorder symptoms, and exercise dependence symptoms. Results Results of the present study confirmed the mediating role of maladaptive perfectionism for eating disorder and exercise dependence symptoms for the male and female exercisers in the maternal data. In the paternal data, maladaptive perfectionism mediated the relationships between paternal psychological control and eating disorder and exercise dependence symptoms as full mediator for female participants and as partial mediator for male participants. Discussion Findings of the present study suggest that it may be beneficial to consider dimensions of maladaptive perfectionism and parental psychological control when studying eating disorder and exercise dependence symptoms in habitual exerciser.

Problematic Exercise in Anorexia Nervosa: Testing Potential Risk Factors against Different Definitions

“Hyperactivity” has a wide prevalence range of 31% to 80% in the anorexia nervosa literature that could be partly due to the plethora of definitions provided by researchers in this field. The purpose of this study was two-fold: 1) To assess the variance across prevalence rates of problematic exercise encountered in patients with anorexia nervosa, in relation to seven different definitions found in the literature. 2) To examine how core eating disorder symptoms and the dimensions of emotional profile are associated with these different definitions and the impact of these definitions on the assessment of patients’ quality of life. Exercise was evaluated in terms of duration, intensity, type and compulsion using a semi-structured questionnaire administered to 180 women suffering from severe anorexia nervosa. Seven different definitions of problematic exercise were identified in the literature: three entailing a single dimension of problematic exercise (duration, compulsion or intensity) and four combining these different dimensions. Emotional profile scores, obsessive-compulsive symptoms, eating disorder symptomatology, worries and concerns about body shape, self-esteem and quality of life were assessed using several established questionnaires. The prevalence of problematic exercise varied considerably from, 5% to 54%, depending on the number of criteria used for its definition. The type and level of eating disorder symptomatology was found to be associated with several definitions of problematic exercise. Surprisingly, a better self-reported quality of life was found among problematic exercisers compared to non-problematic exercisers in three of the definitions. The different definitions of problematic exercise explain the broad prevalence ranges and the conflicting associations generally reported in the literature between problematic exercise and eating disorder-related psychological parameters. There is an urgent need for a valid consensus on the definition of problematic exercise in anorexia nervosa. This will support the development of further research on the etiology and treatment of problematic exercise.

Drive for activity in patients with anorexia nervosa

OBJECTIVE

Hyperactivity and elevated physical activity are both considered symptom characteristics of anorexia nervosa (AN). It has been suggested that a drive for activity (DFA) may underlie these expressions, yet research into DFA in AN remains scant. This study investigated DFA levels in patients with AN and its relation to AN severity. Furthermore, as physical exercise may be a way to reduce negative affect, the influence of negative affect (anxiety) on the role of DFA in AN was tested.

METHOD

Two hundred and forty female patients with AN completed measures for DFA, eating disorder (ED) pathology, anxiety, and clinical parameters.

RESULTS

A strong relation between DFA levels and ED pathology was found, which remained significant even after controlling for negative affect (anxiety).

DISCUSSION

After much theorizing about DFA in AN this study provides empirical evidence for DFA as a hallmark feature of AN, independent of anxiety levels. Future research should shed light on the relationships between DFA, actual physical activity, and the course of AN.

Addictive disorders after Roux-en-Y gastric bypass

BACKGROUND

Recent literature suggests that some patients may develop addictive disorders after bariatric surgery, in particular after Roux-en-Y gastric bypass (RYGB). These may include traditional addictions and so called "behavioral addictions," although prevalence data on the latter have not been published. The objective of this study was to establish the prevalence of addictive behaviors in adults after RYGB.

METHODS

Participants from a large observational study of bariatric surgery who had undergone RYGB were recruited to complete additional measures. Of 241 consented participants, 201 provided data (i.e., Structured Clinical Interview for DSM-IV Axis I [SCID], additional Impulsive Control Disorder Modules, and various self-report measures, including the Alcohol Use Disorder Identification Test [AUDIT]) to assess status before surgery and in the first 3 postoperative years.

RESULTS

Based on the SCID, 16 (8.0%) developed alcohol use disorder [AUD] within 3 years post-RYGB, 7 (43.8%) of whom had no history of AUD. When both the SCID and AUDIT were used to identify AUD, the corresponding numbers/percentages were 32 (18.4%) and 13 (40.6%). Data on other behavioral addictive disorders indicated 19 (9.5%) had a postsurgery disorder, 6 (31.6%) of whom had no history.

CONCLUSION

These data add to a growing literature suggesting there is a substantial risk for the development of AUD after bariatric surgery. Understanding the risk for nondrug-related addictive disorders requires more data from larger studies before clear conclusions can be drawn.

Food restriction-induced hyperactivity: addiction or adaptation to famine?

Increased physical activity is present in 30-80% of anorexia nervosa patients. To explain the paradox of low food intake and excessive exercise in humans and other animals, it has been proposed that increased physical activity along with food restriction activates brain reward circuits and is addictive. Alternatively, the fleeing-famine hypothesis postulates that refusal of known scarce energy-low food sources and hyperactivity facilitate migration towards new habitats that potentially contain new energy-rich foodstuffs. The use of rewarding compounds that differ in energy density, such as the energy-free sweetener saccharin and the energy rich sucrose makes it possible to critically test the reward-addiction and fleeing-famine hypotheses. The aims of the present work were to study if sucrose and/or saccharin could attenuate food restriction-induced hyperactivity, weight loss, increased plasma corticosterone, and activation of brain structures involved in neuroendocrine control, energy balance, physical activity, and reward signaling in rats. Its major findings are that access to sucrose, but not to saccharin, attenuated food restriction-induced running wheel activity, weight loss, rises in plasma corticosterone, and expression of the cellular activation marker c-Fos in the paraventricular and arcuate hypothalamus and in the nucleus accumbens. These findings suggest that the energy-richness and easy availability of sucrose interrupted a fleeing-famine-like hyperactivity response. Since corticosterone mediates food restriction-induced wheel running (Duclos et al., 2009), we propose that the attenuating effect of sucrose consumption on plasma corticosterone plays a role in reduced wheel running and weight loss by lowering activation of the nucleus accumbens and arcuate hypothalamus in these animals.

The moderating effect of gender on ideal-weight goals and exercise dependence symptoms

Background and aims Exercise dependence is implicated in the development of eating disorders and muscle dysmorphic disorder. Although conceptually these disorders represent similar pathologies they largely affect different genders and result in opposite body composition, appearance, and ideal-weight goals (i.e., to gain or lose/maintain weight). Therefore, understanding individuals' ideal-weight goals related to engaging in exercise while simultaneously examining gender differences in exercise dependence symptoms may help to identify those whom may be most at-risk for eating disorders and muscle dysmorphic disorder. The purpose of our study was to examine the moderating effect of gender for exercise dependence symptoms in relation to weight gain, loss, or maintenance goals. Methods Self-reported exercise behavior and exercise dependence symptoms (i.e., Exercise Dependence Scale) were assessed in 513 undergraduate students. Results Our analysis revealed a moderating effect for gender on ideal-weight goals and a gender difference in exercise dependence symptoms. Specifically, men who were dissatisfied with their current weight reported more exercise dependence symptoms than women. Conclusions These results support a growing body of research and extend our understanding of the relationships among exercise dependence and gender specific body-focused psychiatric disorders.

Does anorexia nervosa resemble an addiction?

Anorexia nervosa is a severe psychiatric disorder characterized by unrelenting self-starvation and life-threatening weight loss. The relentlessness with which individuals with anorexia nervosa pursue starvation and in some cases exercise despite the negative physical, emotional, and social consequences parallels features of addictive disorders. From a clinical perspective, individuals with anorexia nervosa behave similarly to individuals with substance abuse by narrowing their behavioral repertoire so that weight loss, restricting food intake, and excessive exercise interfere with other activities in much the same way that substance abuse does. However, fundamental differences exist between anorexia nervosa and substance abuse that suggest anorexia nervosa is not an addiction in and of itself.

Clarifying exercise addiction: differential diagnosis, co-occurring disorders, and phases of addiction

This paper sets out to clarify the unique features of exercise addiction. It begins by examining how this addiction can be distinguished from compulsions and impulse control disorders both of which, like an addiction, involve excessive behavior that creates adverse effects. Assessment of exercise addiction also requires that clinicians be attuned to other forms of excessive behavior, especially eating disorders that can co-occur with exercise. Finally in an effort to clarify exercise addiction, this paper uses the four phases of addiction to examine the attributes of exercise that define it as a healthy habit distinct from an addiction. The paper ends with a discussion of the implications of these topics for effective assessment and treatment.

Exploring Body Weight, Voluntary Activity, and Intrinsic Value in Rats

Modeling activity-based anorexia, food-deprived rats consistently show that activity increases as weight decreases. This effect was explored in 8 food-deprived, Sprague-Dawley rats as potentially mediated by intrinsic value of activity. Running-wheel activity rates were recorded for free-fed weight, reduction to 90% of free-fed weight, and to 80% of free-fed weight. As expected, activity increased as weight decreased. Further, significant differences appeared in the trends of individual run rates when compared across all trials. These individual trends were expressed as varied rates of running, with extreme high and low run rates prevalent. The rewarding nature of exercise itself might serve to predict these trends in individual rats and reveal potential indicators for the development of activity-based anorexia.

Exercise dependence score in patients with longstanding eating disorders and controls: the importance of affect regulation and physical activity intensity

OBJECTIVE

To examine associations among exercise dependence score, amount of physical activity and eating disorder (ED) symptoms in patients with longstanding ED and non-clinical controls.

METHODS

Adult female inpatients (n = 59) and 53 age-matched controls participated in this cross sectional study. Assessments included the eating disorders examination, eating disorders inventory, exercise dependence scale, reasons for exercise inventory, and MTI Actigraph accelerometer.

RESULTS

Positive associations were found among vigorous, not moderate, physical activity, exercise dependence score and ED symptoms in patients. In the controls, ED symptoms were negatively associated with vigorous physical activity and not correlated with exercise dependence score. Exercise for negative affect regulation, not weight/appearance, and amount of vigorous physical activity were explanatory variables for exercise dependence score in both groups.

CONCLUSIONS

The positive associations among exercise dependence score, vigorous physical activity and ED symptoms need proper attention in the treatment of longstanding ED.

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.

Behavioral assessment of the reinforcing effect of exercise in women with anorexia nervosa: further paradigm development and data

OBJECTIVE

To use a Progressive Ratio (PR) computerized "work" paradigm to measure course and correlates of exercise motivation in in-patients with Anorexia Nervosa (AN).

METHOD

Sixteen inpatients with AN participated in a PR task assessing the relative reinforcing effect of two different increments of cash versus the opportunity to exercise for upto 30 min, twice; at low weight, and, for n = 10 participants, after weight restoration.

RESULTS

There was a trend toward a higher work for exercise with 2 versus 5 increments of cash as the alternative reinforcer. Exercise breakpoint did not differ between low and normal-weight states. Exercise breakpoint at each time point was correlated with prehospitalization exercise "commitment" (Commitment to Exercise Scale, r = .613, p = .012 at T1; r = .634, p = .049 at T2).

DISCUSSION

Patients with AN will work at a PR task for access to even a small amount of exercise. Exercise motivation during hospitalization is correlated with prehospital exercise commitment and does not appear to change consistently with weight restoration.

Chromosomal mapping of excessive physical activity in mice in response to a restricted feeding schedule

Excessive physical activity plays an important role in the progression of anorexia nervosa (AN) by accelerating weight loss during dietary restriction. To search for mechanisms underlying this trait, a panel of mouse chromosome substitution strains derived from C57BL/6J and A/J strains was exposed to a scheduled feeding paradigm and to voluntary running wheel (RW) access. Here, we showed that A/J chromosomes 4, 12 and 13 contribute to the development of a disrupted RW activity in response to daily restricted feeding. This pattern is characterized by intense RW activity during the habitual rest phase and leads to accelerated body weight loss. Regions on mouse chromosomes 4, 12 and 13 display homology with regions on human chromosomes linked with anxiety and obsessionality in AN cohorts. Therefore, our data open new roads for interspecies genetic studies of AN and for unraveling novel mechanisms and potential effective treatment strategies for these neurobehavioral traits.

Alcohol Use and Exercise Dependence: Co-Occurring Behaviors Among College Students?

Heavy alcohol consumption is a well-known health compromising addictive behavior. A lesser known addictive behavior that may cause physical and psychological harm is exercise dependence. Research has shown that heavy drinking co-occurs with other addictive behaviors, but until recently little was known about the co-occurrence of alcohol use and exercise dependence. The purpose of the current study was to examine this relationship and assess whether the co-occurrence could be accounted for by personality characteristics. Participants were 283 undergraduate students at a large, Northeastern university. All students reported consuming alcohol in the past 30 days and the majority (95.9%) reported exercising at least occasionally. Results indicated that alcohol use and alcohol-related problems co-occurred with exercise dependence and that personality characteristics did not fully account for the relationship. These findings have implications for clinicians and prevention specialists working with college students and provide several avenues for future research in an innovative area.

Relative reinforcing value of exercise in inpatients with anorexia nervosa: model development and pilot data

OBJECTIVE

This study sought to quantify, among patients hospitalized for the treatment of anorexia nervosa (AN), the reinforcing value of exercise, defined as the amount of work a patient would expend for the opportunity to exercise.

METHOD

Sixteen inpatients with AN performed a computerized progressive ratio (PR) task for the opportunity to exercise for either 15 or 30 min, or a monetary voucher. Exercise "breakpoint" was calculated and compared with clinical measures.

RESULTS

Patients performed an average of 1134.4 (+/-751.2) button presses for exercise. Exercise breakpoint was significantly correlated with the Beck Depression Inventory (BDI; r = .728, p = .001), and there was a trend toward a correlation with the Commitment to Exercise Scale (CES; Davis, 1993; r = .490, p = .054).

CONCLUSION

Results support the feasibility and potential utility of this novel application of the PR task to quantify the reinforcing value of exercise in AN. The association between exercise and depression is consistent with some prior studies in AN. The trend toward an association with CES scores suggests that breakpoint captures an aspect of the motivation for exercise in this population.

Physical activity and cortisol in anorexia nervosa

Elevated physical activity is commonly observed among patients with Anorexia Nervosa (AN) and can manifest in several forms. While elevated physical activity may play a key role in the pathophysiology of this disorder, much remains unknown about it, including the relationship among its various manifestations, and their underlying mechanism(s). The purposes of the current study were to (1) quantify locomotor activity in inpatients with AN using an accelerometer, (2) determine the association between locomotor activity and exercise history and (3) determine the association between urinary cortisol and physical activity. Thirty-six women hospitalized with AN wore activity armbands for 48 h during the first 2 weeks of hospitalization, collected 24-h urine to measure cortisol, and completed rating forms. Activity counts varied more than four-fold among individuals but were consistent within individuals over the 2 monitoring days (p<0.001). Averaged 24-h activity counts were positively correlated with pre-hospitalization attitude towards exercise as measured by the Commitment to Exercise Scale (CES; p=0.032). Forty-two percent of women reported "high" exercise in the 3 months before hospitalization; compared to non-high-exercising patients, these women demonstrated a higher CES score (p<0.001) and a trend toward greater activity counts (p=0.059). Urinary cortisol was positively associated with activity counts (p=0.044) and CES score (p=0.018). These data suggest that some women with AN have a higher "drive" for physical activity that persists into early hospitalization. HPA axis abnormalities may be associated with this state.

The adenosine A2A receptor agonist, CGS-21680, blocks excessive rearing, acquisition of wheel running, and increases nucleus accumbens CREB phosphorylation in chronically food-restricted rats

Adenosine A(2A) receptors are preferentially expressed in rat striatum, where they are concentrated in dendritic spines of striatopallidal medium spiny neurons and exist in a heteromeric complex with D(2) dopamine (DA) receptors. Behavioral and biochemical studies indicate an antagonistic relationship between A(2A) and D(2) receptors. Previous studies have demonstrated that food-restricted (FR) rats display behavioral and striatal cellular hypersensitivity to D(1) and D(2) DA receptor stimulation. These alterations may underlie adaptive, as well as maladaptive, behaviors characteristic of the FR rat. The present study examined whether FR rats are hypersensitive to the A(2A) receptor agonist, CGS-21680. In Experiment 1, spontaneous horizontal motor activity did not differ between FR and ad libitum fed (AL) rats, while vertical activity was greater in the former. Intracerebroventricular (i.c.v.) administration of CGS-21680 (0.25 and 1.0 nmol) decreased both types of motor activity in FR rats, and returned vertical activity levels to those observed in AL rats. In Experiment 2, FR rats given access to a running wheel for a brief period outside of the home cage rapidly acquired wheel running while AL rats did not. Pretreatment with CGS-21680 (1.0 nmol) blocked the acquisition of wheel running. When administered to FR subjects that had previously acquired wheel running, CGS-21680 suppressed the behavior. In Experiment 3, CGS-21680 (1.0 nmol) activated both ERK 1/2 and CREB in caudate-putamen with no difference between feeding groups. However, in nucleus accumbens (NAc), CGS-21680 failed to activate ERK 1/2 and selectively activated CREB in FR rats. These results indicate that FR subjects are hypersensitive to several effects of an adenosine A(2A) agonist, and suggest the involvement of an upregulated A(2A) receptor-linked signaling pathway in NAc. Medications targeting the A(2A) receptor may have utility in the treatment of maladaptive behaviors associated with FR, including substance abuse and compulsive exercise.

Olanzapine reduces physical activity in rats exposed to activity-based anorexia: possible implications for treatment of anorexia nervosa?

BACKGROUND

Anorexia nervosa (AN) patients often show extreme hypophagia and excessive physical activity. Activity-based anorexia (ABA) is considered an animal model of AN and mimics food restriction and hyperactivity in rats. This study investigated whether treatment with olanzapine (Zyprexa) reduces the development of ABA in rats. The effect of olanzapine treatment in AN patients was also evaluated in a small open-label study.

METHODS

Rats were chronically (1 week) infused with olanzapine (7.5 mg/kg) and exposed to the ABA model or ad libitum feeding. Hyperactive AN patients were followed for up to 3 months of olanzapine treatment (5 mg/kg).

RESULTS

Olanzapine treatment reduced development of ABA in rats by reducing running wheel activity, starvation-induced hypothermia and activation of the hypothalamus-pituitary-adrenal axis. Olanzapine treatment reduced activity levels of AN patients compared with untreated AN patients, without affecting body weight and plasma leptin levels.

CONCLUSIONS

Olanzapine treatment reduced wheel running and thereby diminished development of ABA in rats. Olanzapine treatment also reduced physical activity in hyperactive AN patients in a small open-label study. These data support the need for controlled studies investigating the putative beneficial effects of olanzapine treatment in AN patients.

Comorbidity of bipolar and eating disorders: distinct or related disorders with shared dysregulations?

BACKGROUND

The co-occurrence of bipolar and eating disorders, though of major clinical and public health importance, remains relatively unexamined.

METHODS

In reviewing the literature on this comorbidity, we compared bulimia, anorexia nervosa, bulimia nervosa, binge eating disorders and bipolar disorders on phenomenology, course, family history, biology, and treatment response.

RESULTS

Epidemiological studies show an association between subthreshold bipolar disorder and eating disorders in adolescents, and between hypomania and eating disorders, especially binge eating behavior, in adults. Of the clinical studies, most show that patients with bipolar disorder have elevated rates of eating disorders, and vice versa. Finally, the phenomenology, course, comorbidity, family history, and pharmacologic treatment response of these disorders show considerable overlap on all of these parameters. In particular, on phenomenologic grounds--eating dysregulation, mood dysregulation, impulsivity and compulsivity, craving for activity and/or exercise--we find many parallels between bipolar and eating disorders. Overall, the similarities between these disorders were more apparent when examined in their spectrum rather than full-blown expressions.

LIMITATIONS

Despite an extensive literature on each of these disorders, studies examining their overlap across all these parameters are relatively sparse and insufficiently systematic.

CONCLUSIONS

Nonetheless, the reviewed literature leaves little doubt that bipolar and eating disorders--particularly bulimia nervosa and bipolar II disorder--are related. Although several antidepressants and mood stabilizers have shown promise for eating disorders, their clinical use when these disorders co-exist with bipolarity is still very much of an art. We trust that this review will stimulate more rigorous research in their shared putative underlying psychobiologic mechanisms which, in turn, could lead to more rational targeted treatments.

Granisetron attenuates exercise-induced conditioned taste aversion in the rat

A conditioned taste aversion (CTA) paradigm was used in the present study to investigate whether CTA produced by exercise could be attenuated by the 5-HT(3) receptor antagonist granisetron. Male Sprague-Dawley rats were randomly allocated to one of four groups (Ns=6) and were exposed to salty (0.128 M sodium chloride) or sour (0.00138M citric acid) solutions. Subjects were injected with either saline solution (1.0 ml, 0.9%) or granisetron (0.5mg/kg, IP) and were exposed to 30 min of forced wheel running exercise (70 revolutions/30min) 10 min after injection. Exercise induced CTA to both the salty (3.7 ml intake) and sour-flaroured (3.1ml intake) solutions as compared with no exercise (intake 14.0 and 13.7 ml), and administration of granisetron significantly attenuated the exercise-induced CTA to the salty- and sour-flavoured solutions.