Cortisol awakening response in patients with anorexia nervosa or bulimia nervosa: relationships to sensitivity to reward and sensitivity to punishment

Early traumatic experiences and the hypothalamus-pituitary-adrenal axis in people with eating disorders: A narrative review

Exposure to trauma during childhood is a non-specific risk factor for psychiatric disorders, including eating disorders (EDs), over the life course. Moreover, an association between stressful life events and the onset/maintenance of EDs has been documented. Therefore, the hypothalamus-pituitary-adrenal (HPA) axis, namely the main component of the endogenous stress response system, has been proposed to be implicated in the pathophysiology of EDs. In this narrative review the current knowledge concerning the effects of early trauma exposure on the HPA axis activity and their putative role in the pathophysiology of EDs will be illustrated. Research findings corroborate the idea that childhood trauma exposure has long-lasting dysregulating effects on the activity of the HPA axis, which may contribute to the biological background of the early trauma-related risk for the development of EDs across the life span. Moreover, literature data support the existence of a "maltreated ecophenotype" in EDs characterized by specific clinic and neuroendocrine features, which may have important implications in treatment programming for such a type of patients.

Attachment, motivational systems and anorexia nervosa: A systematic review and proposed framework for eating disorders

INTRODUCTION

There is a direct association between patients with insecure attachment style (IAS), behavioural inhibition (BIS) and behavioural activation (BAS) motivational systems, and anorexia nervosa (AN). However, the possible direct relationships between these three variables have not been studied.

OBJECTIVE

The main objective of this study is to analyse the relationship between these variables and propose a framework for analysing and understanding these relationships.

METHODOLOGY

A systematic review was carried out following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines, searching the following terms: 'anorexia', 'attachment' and those related to motivational systems. The final search was limited to publications in English dated between 2014-2022 for 'anorexia and attachment' and 2010-2022 for 'anorexia and BIS/BAS'.

RESULTS

Of the 587 articles retrieved, 30 were included in this study for the textual data analysis of the relationship between anorexia and attachment (17), anorexia and motivational systems (10) and anorexia, attachment and motivational systems (3). An association between avoidant IAS, AN and hypersensitivity to punishment of the BIS was observed in the analysis. A relationship was also observed with hyperreinforcement sensitivity of the BAS. After reviewing the articles, a possible relationship between the three factors, along with other mediating factors, was found.

DISCUSSION

AN is directly related to the avoidant IAS and to BIS. Similarly, bulimia nervosa (BN) was directly related with anxious IAS and BAS. However, contradictions were found in the BN-BAS relationship. This study proposes a framework for analysing and understanding these relationships.

Risk of eating disorders, changes in salivary cortisol concentrations and nutritional status of adolescents

PURPOSE

The imposition of the thin body as an ideal of beauty and the changes that occur in adolescence lead to a constant concern with adolescents' body weight, putting them at risk for eating disorders. Thus, the study sought to investigate associations between eating disorders and salivary cortisol concentrations, nutritional status and depressive symptoms in female adolescents with bulimia.

METHODS

A cross-sectional study was carried out with 1435 adolescents aged 10-19 years. The Bulimic Investigatory Test of Edinburgh (BITE) and Body Shape Questionnaire (BSQ) questionnaires were used. A follow-up study was conducted from a random selection of female adolescents diagnosed with Bulimia Development and Well-Being Assessment-(DAWBA) to assess associations with salivary cortisol concentrations and nutritional status.

RESULTS

The prevalence of body dissatisfaction among adolescents with symptoms of bulimia was 37%. There was a significant difference between salivary cortisol and bulimia (Risk Group = 0.33 ± 0.20 μg/100 ml, Diagnostic Group = 0.44 ± 0.21 μg/100 ml p = 0.040), and correlation positive between the risk of bulimia with symptoms of depression (0.355 p = 0.002) and with Body Mass Index (0.259 p = 0.028). High concentrations of salivary cortisol in bulimic adolescents may be associated with hyperactivity of the hypothalamic-pituitary-adrenal axis and depressive symptoms.

CONCLUSIONS

Nutritional status indicators cannot be used alone for the diagnosis of bulimia, since cortisol levels seem to be a reliable parameter in the identification of bulimia, provided they are used with other diagnostic criteria.

LEVEL III

Evidence obtained from cross-sectional study.

Reward sensitivity modulates the brain reward pathway in stress resilience via the inherent neuroendocrine system

In the previous 10 years, researchers have suggested a critical role for the brain reward system in stress resilience. However, no study has provided an empirical link between activity in the mesostriatal reward regions during stress and the recovery of cortisol stress response. Moreover, although reward sensitivity as a trait has been demonstrated to promote stress resilience, it remains unclear whether it modulates the brain reward system in stress resilience and how this effect is achieved by the inherent neuroendocrine system. To investigate these uncertainties, 70 young adults were recruited to participate in a ScanSTRESS task, and their brain imaging data and saliva samples (for cortisol assay) were collected during the task. In addition, we assessed reward sensitivity, cortisol awakening response, and intrinsic functional connectivity of the brain in all the participants. We found that left putamen activation during stress exposure positively predicted cortisol recovery. In addition, reward sensitivity was positively linked with activation of the left putamen, and this relationship was serially mediated by the cortisol awakening response and right hippocampus-left inferior frontal gyrus intrinsic connectivity. These findings suggest that reward sensitivity modulates reward pathways in stress resilience through the interplay of the diurnal stress response system and network of the hippocampus-prefrontal circuitry. Summarily, the current study built a model to highlight the dynamic and multifaceted interaction between pertinent allostatic factors in the reward-resilience pathway and uncovered new insight into the resilience function of the mesostriatal reward system during stress.

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Cortisol recovery can be predicted by activation of the left putamen in stress.

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Activation of the left putamen was positively linked with reward sensitivity.

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This relationship was serially mediated by the cortisol awakening response and right hippocampus-left inferior frontal gyrus intrinsic coupling.

Dysfunction of Inflammatory Pathways and Their Relationship With Psychological Factors in Adult Female Patients With Eating Disorders

The attempts to clarify the origin of eating disorders (ED) have not been completely successful and their etiopathogenesis remains unknown. Current research shows an activation of the immune response in neuropsychiatric diseases, including ED. We aimed to investigate immune response parameters in patients with ED and to identify psychological factors influencing the inflammatory response. The relationship between inflammation markers and impulsivity and affective symptomatology was explored as well. Thirty-four adult female patients with current diagnosis of ED, none of them under psychopharmacological treatment (excluding benzodiazepines), were included in this study. Patients were compared with a healthy control group of fifteen adult females. The levels of inflammatory markers and indicators of oxidative/nitrosative stress were evaluated in plasma and/or in peripheral blood mononuclear cells (PBMCs). Subjects were assessed by means of different ED evaluation tools. Additionally, the Barratt Impulsiveness Scale, the Montgomery-Asberg Depression Rating Scale and the Hamilton Anxiety Rating Scale were also employed. Patients with ED shown increased plasma levels of the pro-inflammatory nuclear factor kappa B (NFκB) and the cytokine tumor necrosis factor-alpha (TNF-α), among other factors and an increment in the oxidative/nitrosative stress as well as increased glucocorticoid receptor (GR) expression levels in their PBMCs. Moreover, the inflammatory prostaglandin E₂ (PGE₂) correlated with impulsiveness and the anti-inflammatory prostaglandin J₂ (15d-PGJ₂) correlated with depressive symptomatology. Our results point towards a relationship between the immune response and impulsiveness and between the immune response and depressive symptomatology in female adult patients with ED.

Punishment sensitivity and the persistence of anorexia nervosa: High punishment sensitivity is related to a less favorable course of anorexia nervosa

OBJECTIVE

Cross-sectional research provides robust evidence that individuals with anorexia nervosa (AN) report higher punishment sensitivity (PS) than individuals without an eating disorder (ED). High PS might interfere with treatment motivation and the ability to learn from experience. The current study took a longitudinal approach to test predictions that follow from the proposed relevance of PS as a factor in the persistence of AN symptoms. More specifically we tested (1) if higher PS at the start of treatment was related to less improvement in ED symptoms after one year, and (2) if a decrease in ED symptoms was associated with a concurrent decrease in PS.

METHOD

Participants were 69 adolescents with a diagnosis of AN at the start of treatment of whom 62 participated again one year later. ED symptom severity and PS were assessed at both time points.

RESULTS

Findings showed that (1) higher PS at the start of treatment was related to less improvement in ED symptoms, and (2) an improvement in ED symptoms was related to a decrease in PS.

DISCUSSION

These findings are consistent with the proposed relevance of PS in the persistence of AN and suggest that it might be beneficial to address high PS in treatment.

PUBLIC SIGNIFICANCE

Consistent with the view that punishment sensitivity (PS) is related to the persistence of anorexia nervosa, high PS at the start of treatment was related to less improvement in eating disorder symptoms in patients with anorexia nervosa. Furthermore, an improvement in eating disorder symptoms was associated with a concurrent decrease in PS, suggesting that PS can be subject to change and may be a relevant target for treatment.

Dissociable hormonal profiles for psychopathology and stress in anorexia and bulimia nervosa

BACKGROUND

Anorexia nervosa (AN) and bulimia nervosa (BN) are complex psychiatric conditions, in which both psychological and metabolic factors have been implicated. Critically, the experience of stress can precipitate loss-of-control eating in both conditions, suggesting an interplay between mental state and metabolic signaling. However, associations between psychological states, symptoms and metabolic processes in AN and BN have not been examined.

METHODS

Eighty-five women (n = 22 AN binge/purge subtype, n = 33 BN, n = 30 controls) underwent remote salivary cortisol sampling and a 2-day, inpatient study session to examine the effect of stress on cortisol, gut hormones [acyl-ghrelin, peptide tyrosine tyrosine (PYY) and glucagon-like peptide-1] and food consumption. Participants were randomized to either an acute stress induction or control task on each day, and plasma hormones were serially measured before a naturalistic, ad libitum meal.

RESULTS

Cortisol-awakening response was augmented in AN but not in BN relative to controls, with body mass index explaining the most variance in post-awakening cortisol (36%). Acute stress increased acyl-ghrelin and PYY in AN compared to controls; however, stress did not alter gut hormone profiles in BN. Instead, a group-by-stress interaction showed nominally reduced cortisol reactivity in BN, but not in AN, compared to controls. Ad libitum consumption was lower in both patient groups and unaffected by stress.

CONCLUSIONS

Findings extend previous reports of metabolic dysfunction in binge-eating disorders, identifying unique associations across disorders and under stress. Moreover, we observed disrupted homeostatic signaling in AN following psychological stress, which may explain, in part, the maintenance of dysregulated eating in this serious illness.

The peril and promise of sensitivity in eating disorders

Differential susceptibility, a reconceptualization of the diathesis-stress model of psychopathology, describes gene-environment interactions that reflect individual differences in responsiveness to environmental influences, both detrimental and beneficial. This model has been described metaphorically by the classification of orchids, which thrive under optimal care but wither under adverse conditions, and dandelions, which weather broad environmental circumstances but are less responsive to careful cultivation. Etiological research in the field of eating disorders has largely focused on the identification of specific behavioral phenotypes, temperamental traits, genotypes and neurobiological processes that confer risk. In this article, we propose that these putative vulnerability factors represent phenotypes and endophenotypes of a genetic predisposition towards environmental sensitivity. We assert that this sensitivity not only transmits eating disorder risk but also confers resilience, depending on the circumstances. In particular, we propose that differential susceptibility can be used as a framework to organize disparate temperamental and neurobiological findings and their complex interplay with various developmental, environmental and sociocultural influences to increase eating disorder risk and treatment responsiveness. Finally, we assert that viewed through the lens of differential susceptibility, sensitivity can be leveraged to refine our interventions and develop novel treatment and prevention strategies to support favorable outcomes for individuals with eating disorders.

The Role of the Noradrenergic System in Eating Disorders: A Systematic Review

Noradrenaline (NE) is a catecholamine acting as both a neurotransmitter and a hormone, with relevant effects in modulating feeding behavior and satiety. Several studies have assessed the relationship between the noradrenergic system and Eating Disorders (EDs). This systematic review aims to report the existing literature on the role of the noradrenergic system in the development and treatment of EDs. A total of 35 studies were included. Preclinical studies demonstrated an involvement of the noradrenergic pathways in binge-like behaviors. Genetic studies on polymorphisms in genes coding for NE transporters and regulating enzymes have shown conflicting evidence. Clinical studies have reported non-unanimous evidence for the existence of absolute alterations in plasma NE values in patients with Anorexia Nervosa (AN) and Bulimia Nervosa (BN). Pharmacological studies have documented the efficacy of noradrenaline-modulating therapies in the treatment of BN and Binge Eating Disorder (BED). Insufficient evidence was found concerning the noradrenergic-mediated genetics of BED and BN, and psychopharmacological treatments targeting the noradrenergic system in AN. According to these data, further studies are required to expand the existing knowledge on the noradrenergic system as a potential target for treatments of EDs.

Are Sensitivity to Punishment, Sensitivity to Reward and Effortful Control Transdiagnostic Mechanisms Underlying the Eating Disorder/Obesity Spectrum?

Although it has been postulated that eating disorders (EDs) and obesity form part of a broad spectrum of eating- and weight-related disorders, this has not yet been tested empirically. In the present study, we investigated interindividual differences in sensitivity to punishment, sensitivity to reward, and effortful control along the ED/obesity spectrum in women. We used data on 286 patients with eating disorders (44.6% AN-R, 24.12% AN-BP, and 31.82% BN), 126 healthy controls, and 640 Class II/III obese bariatric patients (32.81% Class II and 67.19% Class III) with and without binge eating. Participants completed the behavioral inhibition and behavioral activation scales, as well as the effortful control scale, to assess sensitivity to punishment and reward and effortful control. Results showed that patients with EDs scored significantly higher on punishment sensitivity (anxiety) compared to healthy controls and Class II/III obese patients; the different groups did not differ significantly on reward sensitivity. Patients with binge eating or compensatory behaviors scored significantly lower on effortful control than patients without binge eating. Differences in temperamental profiles along the ED/obesity spectrum appear continuous and gradual rather than categorical. This implies that it may be meaningful to include emotion regulation and impulse regulation training in the treatment of both EDs and obesity.

Alexithymia and cortisol awakening response in people with eating disorders

OBJECTIVES

Alexithymia, which is the inability to recognise and describe one's own emotions, is a transdiagnostic feature across eating disorders (EDs) and it has been associated with prolonged stress exposure. Therefore, we evaluated whether alexithymia was associated with hypothalamus-pituitary-adrenal (HPA) axis functioning, the main endogenous stress response system, in patients with anorexia nervosa (AN) or bulimia nervosa (BN).

METHODS

26 women with AN and 26 with BN participated in the study. Alexithymia was evaluated by the Toronto Alexithymia Scale-20 and eating-related psychopathology was measured by the Eating Disorder Inventory-2. The activity of the HPA axis was assessed by measuring the salivary cortisol awakening response (CAR).

RESULTS

The prevalence of alexithymia did not differ significantly between the two diagnostic groups. Alexithymia was associated with more severe eating-related psychopathology in AN women but not in BN women. A significant reduction in the magnitude of CAR occurred in alexithymic patients with BN compared to non-alexithymic patients, but not in alexithymic women with AN.

CONCLUSIONS

These results confirm the presence of a more severe specific psychopathology in alexithymic individuals with AN and show, for the first time, an association between alexithymia and a dampened basal activity of the HPA axis in BN.

Perceived parental bonding and cortisol awakening response in people with eating disorders

It is widely acknowledged that early life experiences may have an impact on hypothalamic-pituitary-adrenal (HPA) axis functioning in eating disorders (EDs). Parental bonding is defined as the parental contribution of care and control to parent-child relationships. We evaluated whether perceived care and protection of parental bonding in childhood and adolescence were associated with HPA axis functioning in adult patients with EDs. Sixty-four women with EDs participated in the study, 37 with anorexia nervosa and 27 with bulimia nervosa. Parental care and control (separately for the mother and father) were evaluated by the Parental Bonding Instrument. The activity of the HPA axis was assessed by measuring the salivary cortisol awakening response (CAR). Parental care and control did not differ significantly between the two diagnostic groups. High and low maternal care were associated with significantly different time patterns of CAR without any significant difference in the overall post-awakening production of cortisol. Maternal control, paternal care and paternal control were not associated with any difference in the CAR. Our results showed for the first time an association of perceived maternal care with the time pattern of CAR in female patients with EDs, while perceived parental control was not associated with any CAR feature. These findings support the idea that perceived characteristics of parental bonding in childhood and adolescence may influence the HPA axis activity in adults with EDs.

Reward and Punishment Sensitivity in Borderline and Avoidant Personality Disorders

The authors compared self-reported and behavioral responses to reward and punishment in individuals diagnosed with borderline personality disorder (BPD) or avoidant personality disorder (APD) relative to a healthy comparison (HC) group. As predicted, self-reported sensitivity to reward was significantly higher in the BPD group than in the APD and HC groups. Also as predicted, self-reported sensitivity to punishment was significantly elevated in both disordered groups but significantly higher in APD than in BPD. These hypothesized patterns were also evident in responses to behavioral tasks: Participants with BPD made more errors of commission and fewer errors of omission than HC participants on a passive avoidance learning task, and participants with APD showed greater reactivity to losses than other participants on a probabilistic reversal learning task. Results help characterize differences between these two disorders.

Deciphering the Association Between Hypothalamus-Pituitary-Adrenal Axis Activity and Obesity: A Meta-Analysis

OBJECTIVE

Both the cortisol awakening response (CAR; corresponding to the state measurement) and hair cortisol concentration (HCC; corresponding to the trait measurement) are considered reliable markers of hypothalamus-pituitary-adrenal axis activity. Because cortisol has long been associated with adiposity, this systematic review and meta-analysis aims to summarize and compare the literature around CAR and HCC and their association with obesity or fat distribution indices.

METHODS

The PubMed, Web of Science (Web of Science Core Collection and Medline), EBSCO Information Services, Embase, and PsycNET databases were searched, and full-text articles investigating the association between CAR or HCC and markers of adiposity in humans were included. Meta-analyses were then performed to compare studies associating CAR or HCC with BMI (a marker of general adiposity) and waist circumference (a marker of fat distribution).

RESULTS

The results of this review highlight inconsistencies in cortisol sampling and CAR computation, which makes comparisons between studies difficult. It was found that adiposity indices are not associated with CAR but that they correlate significantly and positively with HCC. The subgroup analysis hinted to possible age differences in the magnitude of the association between HCC and BMI.

CONCLUSIONS

Trait rather than state measurement of the hypothalamus-pituitary-adrenal axis activity is associated with increased general and abdominal adiposity in humans.

Effects of Microbiota Imbalance in Anxiety and Eating Disorders: Probiotics as Novel Therapeutic Approaches

Anxiety and eating disorders produce a physiological imbalance that triggers alterations in the abundance and composition of gut microbiota. Moreover, the gut–brain axis can be altered by several factors such as diet, lifestyle, infections, and antibiotic treatment. Diet alterations generate gut dysbiosis, which affects immune system responses, inflammation mechanisms, the intestinal permeability, as well as the production of short chain fatty acids and neurotransmitters by gut microbiota, which are essential to the correct function of neurological processes. Recent studies indicated that patients with generalized anxiety or eating disorders (anorexia nervosa, bulimia nervosa, and binge-eating disorders) show a specific profile of gut microbiota, and this imbalance can be partially restored after a single or multi-strain probiotic supplementation. Following the PRISMA methodology, the current review addresses the main microbial signatures observed in patients with generalized anxiety and/or eating disorders as well as the importance of probiotics as a preventive or a therapeutic tool in these pathologies.

Coping strategies and stress-induced natural killer cell redistribution in women with eating disorders

BACKGROUND

Patients with eating disorders (ED) are very sensitive and responsive to psychosocial stress. Stress response includes changes in immune cell distribution and may be modulated by the capability to cope with stressors. Thus, the present study sought to analyze the association between coping strategies and immune response (natural killer [NK] cell redistribution following psychosocial stress) in patients with anorexia nervosa (AN) and bulimia nervosa (BN) and healthy controls (HC).

METHOD

Twenty-four AN patients, 29 BN patients, and 58 HC were studied. A multidimensional assessment tool, the COPE Inventory, was used to assess coping strategies. The number of NK cells was quantified in peripheral blood before and after the application of the Trier Social Stress Test (TSST). Potentially mediating variables, such as weight status, severity of eating pathology, depression, anxiety, and impulsivity were controlled.

RESULTS

The three groups differed in intensity and direction of cell redistribution: The TSST was followed in BN patients by a significant decrease in the number of NK cells, whereas HC displayed a moderate decrease and AN a clear increase. Specific correlations between coping strategies and NK cell mobilization were found, especially in BN patients (positive for "planning" and negative for "substance abuse").

CONCLUSION

Recognition and subsequent modification of the dysfunctional coping strategies used by patients with ED could contribute to improving their immune status, strengthening their resilience and increasing their ability to overcome the disease.

Heightened self-reported punishment sensitivity, but no differential attention to cues signaling punishment or reward in anorexia nervosa

This study examined whether adolescents with anorexia nervosa (AN) are more sensitive to punishment and less sensitive to reward than a non-eating disorder comparison group. Both self-report and performance measures were used to index reward and punishment sensitivity. Participants were adolescents with AN (n = 69) and an individually matched comparison group with healthy weight (n = 69). They completed the Behavioral Inhibition Scale/Behavioral Activation Scale and the Sensitivity to Punishment and Sensitivity to Reward Questionnaire to index self-reported reward and punishment sensitivity, and performed the Spatial Orientation Task to index attention to cues signaling reward and punishment. There was extremely strong evidence (BF₁₀ > 100), that adolescents with AN reported higher sensitivity to punishment than adolescents without an eating disorder. However, adolescents with AN did not differ from the comparison group on self-reported reward sensitivity, and attention to cues signaling reward or punishment. Adolescents with AN clearly show heightened punishment sensitivity, yet this was not paralleled by a heightened proneness to detect signals of punishment. An important next step would be to examine whether punishment sensitivity is a reliable risk factor for the development or maintenance of AN.

Dysfunction of inflammatory pathways in adolescent female patients with anorexia nervosa

BACKGROUND

The pathogenesis of Eating Disorders is still unknown. However, a growing body of evidence shows that there are changes in cytokine levels and an alteration in the stress response in patients with anorexia nervosa (AN). For this reason, we decided to test whether there are differences in immune parameters involved in the regulation of the inflammatory response between female adolescents with AN and healthy adolescents.

METHODS

The sample 27 drug-naïve AN patients the study sample included 27 AN patients at a very early stage of the disease and 23 healthy controls. Plasma and peripheral blood mononuclear cells (PBMCs) were obtained for biochemical study.

RESULTS

Plasma levels of the pro-inflammatory cytokines TNF-α and IL-1β were significantly increased in patients with AN, while the levels of prostaglandins PGE₂ (proinflammatory) and 15d-PGJ₂, (anti-inflammatory) were lower compared with controls. Protein expression in PBMCs of cyclooxygenase-2 (COX-2) and the activated forms of the mitogen-activated protein kinases p38 and ERK were also increased in the AN group. Expression levels of the anti-inflammatory factor peroxisome proliferator-activated receptor gamma (PPARγ) were significantly decreased in patients. Plasma levels of lipid peroxidation markers -TBARS- were not increased in patients with AN. Components of the biochemical inflammatory response (COX-2, PGE₂, TBARS, 15d-PGJ₂, ERK, p65 NFκB) and glucocorticoid receptor -GR- expression and the scores on the impulsivity measures in the BARRATT, EDI and BITE questionnaires showed a significant correlation within the AN patients group.

CONCLUSIONS

The results for female adolescent patients with AN indicate that there is a dysfunction of intra- and intercellular inflammatory pathways characterized by higher levels of pro-inflammatory parameters in plasma and a decrease in one of the controlling cytoplasmic-nuclear pathways implicated in their modulation (i.e. PPARγ) with, at this very early stage of the disease, no effect on oxidative stress markers plasma levels. Most notably, higher severity of illness (restrictive and purging behaviour) correlated with higher levels of inflammatory markers.

Stress hormones and eating disorders

AIMS

The aim of this paper is to emphasize the role of stress processes in the aetiology of eating disorders.

METHODS

We have examined the literature for evidence that people with eating disorders might exhibit markers of stress and show signs of the "maltreated ecophenotype".

RESULTS

Early adversity is more common among people with binge eating behaviours. The secondary effects of malnutrition, which are mostly marked in anorexia nervosa, may be an added stressor that could also contribute to the stress related phenotype. People with eating disorders have anomalies in brain structure, reward and punishment sensitivity, and the balance between HPA and SMA function. These may be potential targets for treatment.

Neuroendocrinology of reward in anorexia nervosa and bulimia nervosa: Beyond leptin and ghrelin

The pathophysiology of anorexia nervosa (AN) and bulimia nervosa (BN) are still poorly understood, but psychobiological models have proposed a key role for disturbances in the neuroendocrines that signal hunger and satiety and maintain energy homeostasis. Mounting evidence suggests that many neuroendocrines involved in the regulation of homeostasis and body weight also play integral roles in food reward valuation and learning via their interactions with the mesolimbic dopamine system. Neuroimaging data have associated altered brain reward responses in this system with the dietary restriction and binge eating and purging characteristic of AN and BN. Thus, neuroendocrine dysfunction may contribute to or perpetuate eating disorder symptoms via effects on reward circuitry. This narrative review focuses on reward-related neuroendocrines that are altered in eating disorder populations, including peptide YY, insulin, stress and gonadal hormones, and orexins. We provide an overview of the animal and human literature implicating these neuroendocrines in dopaminergic reward processes and discuss their potential relevance to eating disorder symptomatology and treatment.

The potential of calibrated fMRI in the understanding of stress in eating disorders

Eating disorders (ED), including Anorexia Nervosa (AN), Bulimia Nervosa (BN), and Binge Eating Disorder (BED), are medically dangerous psychiatric disorders of unknown etiology. Accumulating evidence supports a biopsychosocial model that includes genetic heritability, neurobiological vulnerability, and psychosocial factors, such as stress, in the development and maintenance of ED. Notably, stress hormones influence appetite and eating, and dysfunction of the physiological stress response has been implicated in ED pathophysiology. Stress signals also appear associated with food reward neurocircuitry response in ED, providing a possible mechanism for the role of stress in appetite dysregulation. This paper provides a review of some of the interacting psychological, behavioral, physiological, and neurobiological mechanisms involved in the stress response among individuals with ED, and discusses novel neuroimaging techniques to address potential physiological confounds of studying neural correlates of stress in ED, such as calibrated fMRI.

Similarities and differences in revised reinforcement sensitivities across eating disorder subtypes

Reinforcement Sensitivity Theory has been used to investigate personality in the development and maintenance of disordered eating. However, the vast majority of research from this perspective has been limited by the use of measures developed to assess the original theory, rather than the significantly revised theory, potentially overlooking key personality differences in eating disorder subtypes. The current study aimed to overcome limitations when using measures based on the original theory by investigating differences and similarities in reinforcement sensitivity across eating disorder subtypes and healthy controls. The measure based on the revised theory assesses i) reward sensitivity [goal-drive persistence; reward interest, reward reactivity], ii) impulsivity, iii) behavioural inhibition, and iv) threat sensitivity. A total of 374 women from the community participated, including those with a past or present AN-R diagnosis (AN-R = 109); those with a past or present binge-type ED (Binge-type = 132); and healthy controls (HC = 133). Participants completed a questionnaire assessing personality, eating disorder symptoms, and past or present eating disorder diagnoses. Results showed that both the AN-R and Binge-type groups were higher in behavioural inhibition and threat sensitivity compared to the HC group. The Binge-type group showed higher impulsivity relative to the AN-R and HC group, and lower Goal-Drive Persistence relative to the HC group. The AN-R group showed lower Reward Interest and Reward Responsiveness relative to the HC group. This study supports and extends previous research with the findings of heightened threat and anxiety sensitivity in those with diagnosed eating disorders. Additionally, among those with a past or present eating disorder, the findings implicate impulsivity in differentiating bingeing versus restricting subtypes.

Impaired cortisol awakening response in eating disorder women with childhood trauma exposure: evidence for a dose-dependent effect of the traumatic load

BACKGROUND

Childhood trauma is a non specific risk factor for adult eating disorders (ED), and the hypothalamic-pituitary-adrenal (HPA) axis seems to mediate such a risk. Here we explored the impact of different types of childhood trauma and of traumatic load on the cortisol awakening response (CAR) of women with anorexia nervosa (AN) or bulimia nervosa (BN).

METHODS

Saliva samples were collected at awakening and after 15, 30, 60 min to measure cortisol levels by 121 women (44 AN patients, 36 BN patients and 41 healthy women). Participants filled in the Childhood Trauma Questionnaire.

RESULTS

AN and BN patients with childhood maltreatment exhibited an attenuated CAR compared with non-maltreated ones. In the whole ED patient group, the CAR showed a progressive impairment with the increasing number of reported trauma types. Although significant negative correlations emerged between the type or the number of traumas and the CAR, only the number of traumas remained significantly associated with the CAR in a stepwise multiple regression analysis.

CONCLUSIONS

Present findings confirm that childhood trauma is associated with an impaired CAR in adult AN and BN patients and demonstrate for the first time a negative dose-dependent effect of the traumatic load on HPA axis activity.

Update on Psychological Trauma, Other Severe Adverse Experiences and Eating Disorders: State of the Research and Future Research Directions

PURPOSE OF REVIEW

This paper provides an updated review of the literature on the relationship between psychological trauma exposure, other severe adverse experiences, and eating disorders.

RECENT FINDINGS

Trauma exposure and other severe adverse experiences (e.g., emotional abuse) in both childhood and adulthood are associated with eating disorders. The relationship between traumatic and other adverse experiences and eating disorders appears to be mediated by emotional and behavioral dysregulation, as well as by cognitive factors such as self-criticism. Biological vulnerabilities may also be relevant to this relationship. Overall, the literature is limited by predominantly cross-sectional designs. There is clear evidence of a correlational relationship between trauma exposure and other severe adverse events, and eating disorders. Both risk and maintenance factor hypotheses have been put forth; however, prospective research testing these hypotheses remains limited. Future research should use prospective designs and focus on trauma-related symptoms (rather than trauma exposure) in order to advance research on risk and maintaining factors for eating disorders and inform treatment directions.

Cortisol and DHEA in development and psychopathology

Dehydroepiandrosterone (DHEA) and cortisol are the most abundant hormones of the human fetal and adult adrenals released as end products of a tightly coordinated endocrine response to stress. Together, they mediate short- and long-term stress responses and enable physiological and behavioral adjustments necessary for maintaining homeostasis. Detrimental effects of chronic or repeated elevations in cortisol on behavioral and emotional health are well documented. Evidence for actions of DHEA that offset or oppose those of cortisol has stimulated interest in examining their levels as a ratio, as an alternate index of adrenocortical activity and the net effects of cortisol. Such research necessitates a thorough understanding of the co-actions of these hormones on physiological functioning and in association with developmental outcomes. This review addresses the state of the science in understanding the role of DHEA, cortisol, and their ratio in typical development and developmental psychopathology. A rationale for studying DHEA and cortisol in concert is supported by physiological data on the coordinated synthesis and release of these hormones in the adrenal and by their opposing physiological actions. We then present evidence that researching cortisol and DHEA necessitates a developmental perspective. Age-related changes in DHEA and cortisol are described from the perinatal period through adolescence, along with observed associations of these hormones with developmental psychopathology. Along the way, we identify several major knowledge gaps in the role of DHEA in modulating cortisol in typical development and developmental psychopathology with implications for future research.

Perinatal hypothalamic-pituitary-adrenal axis regulation among women with eating disorders and their infants

BACKGROUND

Psychiatric illness is associated with heightened hypothalamic-pituitary-adrenal (HPA) axis activity during pregnancy which may have long term effects on infant stress regulation. HPA axis regulation has not previously been investigated in women with eating disorders (ED) or their infants during the perinatal period.

METHODS

Women were recruited to a prospective longitudinal study in three groups: 1) current or active ED (C-ED=31), 2) past ED (P-ED=29) and healthy control (HC=57). Maternal psychopathology, diurnal cortisol levels, corticotropin-releasing hormone (CRH) and CRH binding protein (CRH-BP) were measured during the third trimester of pregnancy. At eight weeks postpartum infant cortisol was obtained before and after routine immunisations to determine infant hormonal response to a stressful situation.

RESULTS

Women with current ED had a significantly lower cortisol decline throughout the day compared to HC, in both adjusted and unadjusted analyses. Lower cortisol decline among women with a current ED were associated with higher levels of psychopathology during pregnancy. Women's cortisol awakening response, CRH and CRH-BP levels did not differ across the three groups. Infants' stress response was also significantly higher among those in the C-ED group, although this effect was attenuated after controlling for confounders.

CONCLUSIONS

During pregnancy women with ED have lower cortisol declines, suggestive of blunted diurnal cortisol rhythms. Postnatally, their infants also have a heightened response to stress. This is the first study to identify HPA axis dysfunction in pregnancy in women with ED, and to show an intergenerational effect. Since dysfunctions in HPA activity during childhood may represent a risk factor for psychological and physical health problems later in life, further investigation of the potential long-term implications of these findings is crucial.

Reward and punishment sensitivity and disordered eating behaviors in men and women

BACKGROUND

Reward and punishment sensitivities have been identified as potential contributors to binge eating and compensatory behaviors, though few studies have examined gender differences in these behaviors.

METHOD

A college-aged sample (N = 1,022) completed both the Eating Disorders Diagnostic Scale (EDDS) and Sensitivity to Punishment/Sensitivity to Reward Questionnaire (SPSRQ).

RESULTS

Rates of binge eating were similar in males and females. Among those reporting compensatory behaviors, women reported engaging in compensatory behaviors more frequently than men. Sensitivity to reward and sensitivity to punishment were both positively associated with binge eating frequency in both genders. In contrast, women with high reward sensitivity reported engaging in compensatory behaviors more frequently.

CONCLUSIONS

Rates of binge eating and compensatory weight control behaviors were similar between college-aged males and females, though females who engaged in compensatory behaviors did so more frequently than males. Sensitivity to punishment was greater in females, whereas sensitivity to reward was greater in males. Reward and punishment sensitivity were each positively associated with binge eating in both males and females, while only reward sensitivity was positively associated with compensatory behaviors in females.

The physiology of functional hypothalamic amenorrhea associated with energy deficiency in exercising women and in women with anorexia nervosa

An energy deficiency is the result of inadequate energy intake relative to high energy expenditure. Often observed with the development of an energy deficiency is a high drive for thinness, dietary restraint, and weight and shape concerns in association with eating behaviors. At a basic physiologic level, a chronic energy deficiency promotes compensatory mechanisms to conserve fuel for vital physiologic function. Alterations have been documented in resting energy expenditure (REE) and metabolic hormones. Observed metabolic alterations include nutritionally acquired growth hormone resistance and reduced insulin-like growth factor-1 (IGF-1) concentrations; hypercortisolemia; increased ghrelin, peptide YY, and adiponectin; and decreased leptin, triiodothyronine, and kisspeptin. The cumulative effect of the energetic and metabolic alterations is a suppression of the hypothalamic-pituitary-ovarian axis. Gonadotropin releasing hormone secretion is decreased with consequent suppression of luteinizing hormone and follicle stimulating hormone release. Alterations in hypothalamic-pituitary secretion alters the production of estrogen and progesterone resulting in subclinical or clinical menstrual dysfunction.

An Integrative Bio-Psycho-Social Theory of Anorexia Nervosa

The need for novel approaches to understanding and treating anorexia nervosa (AN) is well recognized. The aim of this paper is to describe an integrative bio-psycho-social theory of maintaining factors in AN. We took a triangulation approach to develop a clinically relevant theory with face validity and internal consistency. We developed theoretical ideas from our clinical practice and reviewed theoretical ideas within the eating disorders and wider bio-psycho-social literature. The synthesis of these ideas and concepts into a clinically meaningful framework is described here. We suggest eight key factors central to understanding the maintenance and treatment resistance of anorexia nervosa: genetic or experiential predisposing factors; dysfunctional feelings processing and regulation systems; excessive vulnerable feelings; 'feared self' beliefs; starvation as a maladaptive physiological feelings regulation mechanism; maladaptive psychological coping modes; maladaptive social behaviour; and unmet physical and psychological core needs. Each of these factors serves to maintain the disorder. The concept of universal physical and psychological core needs can provide an underpinning integrative framework for working with this distinctly physical and psychological disorder. This framework could be used within any treatment model. We suggest that treatments which help address the profound lack of trust, emotional security and self-acceptance in this patient group will in turn address unmet needs and improve well-being. Copyright © 2016 John Wiley & Sons, Ltd.

KEY PRACTITIONER MESSAGE

The concept of unmet physical and psychological needs can be used as an underlying integrative framework for understanding and working with this patient group, alongside any treatment model. A functional understanding of the neuro-biological, physiological and psychological mechanisms involved in anorexia nervosa can help patients reduce self-criticism and shame. Fears about being or becoming fat, greedy, needy, selfish and unacceptable ('Feared Self') drive over-compensatory self-depriving behaviour ('Anorexic Self'). Psychological treatment for anorexia nervosa should emphasize a focus on feelings and fostering experiences of acceptance and trust. Treatment for patients with anorexia nervosa needs to be longer than current clinical practice.

Underweight subjects with anorexia nervosa have an enhanced salivary cortisol response not seen in weight restored subjects with anorexia nervosa

The cortisol response to awakening (CAR) has been reported to be enhanced in symptomatic patients with anorexia nervosa (AN). However, it has been not established whether the dysregulation of CAR was a primary phenomenon or a change secondary to malnutrition. Therefore, we aimed to explore the salivary CAR in both underweight and weigh-restored women with AN. Fifty-nine women volunteered for the study. They were 18 underweight AN women, 15 weight-restored AN women and 26 normal-weight healthy women. Saliva samples were collected in the morning, immediately on awakening and after 15, 30 and 60min to measure saliva levels of cortisol. Participants' anxiety levels in the morning of sampling were measured by the State-Trait Anxiety Inventory. As compared to control women, underweight AN patients showed an enhanced CAR whereas weight-restored patients had a normal CAR. These results could be not explained by group differences in body mass index or levels of anxiety. These findings show, for the first time, that the enhanced CAR occurring in the acute phase of AN is not seen in weight-recovered patients, suggesting that the dysregulated activity of the hypothalamus-pituitary-adrenal axis of symptomatic AN patients is a state-dependent phenomenon.

Hormonal Factors and Disturbances in Eating Disorders

This review summarizes the current state of the literature regarding hormonal correlates of, and etiologic influences on, eating pathology. Several hormones (e.g., ghrelin, CCK, GLP-1, PYY, leptin, oxytocin, cortisol) are disrupted during the ill state of eating disorders and likely contribute to the maintenance of core symptoms (e.g., dietary restriction, binge eating) and/or co-occurring features (e.g., mood symptoms, attentional biases). Some of these hormones (e.g., ghrelin, cortisol) may also be related to eating pathology via links with psychological stress. Despite these effects, the role of hormonal factors in the etiology of eating disorders remains unknown. The strongest evidence for etiologic effects has emerged for ovarian hormones, as changes in ovarian hormones predict changes in phenotypic and genetic influences on disordered eating. Future studies would benefit from utilizing etiologically informative designs (e.g., high risk, behavioral genetic) and continuing to explore factors (e.g., psychological, neural responsivity) that may impact hormonal influences on eating pathology.

Behavioral and neurodevelopmental precursors to binge-type eating disorders: support for the role of negative valence systems

BACKGROUND

Pediatric loss-of-control (LOC) eating is a robust behavioral precursor to binge-type eating disorders. Elucidating precursors to LOC eating and binge-type eating disorders may refine developmental risk models of eating disorders and inform interventions.

METHOD

We review evidence within constructs of the Negative Valence Systems (NVS) domain, as specified by the Research Domain Criteria framework. Based on published studies, we propose an integrated NVS model of binge-type eating-disorder risk.

RESULTS

Data implicate altered corticolimbic functioning, neuroendocrine dysregulation, and self-reported negative affect as possible risk factors. However, neuroimaging and physiological data in children and adolescents are sparse, and most prospective studies are limited to self-report measures.

CONCLUSIONS

We discuss a broad NVS framework for conceptualizing early risk for binge-type eating disorders. Future neural and behavioral research on the developmental trajectory of LOC and binge-type eating disorders is required.

Childhood trauma and cortisol awakening response in symptomatic patients with anorexia nervosa and bulimia nervosa

OBJECTIVE

Exposure to trauma during childhood is a risk factor for eating disorders (EDs) in adulthood. The biological mechanisms underlying such increased risk seem to involve the endogenous stress response system (i.e., the hypothalamic-pituitary-adrenal [HPA] axis), which undergoes trauma-induced functional changes that may persist later in life. In the present study, we examined the effects of childhood trauma experiences on HPA-axis activity, comparing saliva cortisol awakening response (CAR) in adult patients with anorexia nervosa (AN) or bulimia nervosa (BN) with CAR in adult healthy controls.

METHOD

Twenty-three patients with symptomatic AN, 21 patients with symptomatic BN, and 29 healthy women collected saliva samples at awakening and again after 15, 30, and 60 min. Participants also completed the Childhood Trauma Questionnaire and eating-related psychopathological rating scales.

RESULTS

According to the Childhood Trauma Questionnaire, 13 individuals with AN and 12 individuals with BN, but none of the healthy women, reported childhood maltreatment. Compared with the control group, the non-maltreated AN patient group exhibited an enhanced CAR, whereas the group of non-maltreated BN patients showed a normal CAR. Moreover, both AN and BN patient groups with childhood maltreatment exhibited statistically significant blunting of CAR compared with non-maltreated groups.

DISCUSSION

The present findings add to the evidence supporting the concept that there is a dysregulation of HPA-axis activity in symptomatic patients with EDs and suggest that childhood trauma exposure may contribute to such dysregulation.