Bulimic vomiting alters pain tolerance and mood

Blunted Cold Pressor-Induced Cortisol but not Total Ghrelin Response in Women with Bulimia Nervosa following a Standardized Sweet-Fat Liquid Meal

BACKGROUND

Bulimia nervosa (BN) involves recurrent episodes of uncontrolled eating followed by compensatory behaviors. Stress is implicated in BN, affecting the hypothalamic-pituitary-adrenal (HPA) axis and ghrelin, a key appetite-regulating hormone. Studies report conflicting HPA axis findings in BN, necessitating further investigation.

OBJECTIVE

To examine the impact of acute stress on cortisol and serum ghrelin and eating disorder symptoms in women with BN and healthy controls (HC).

METHODS

Participants underwent a socially evaluated cold pressor test (CPT) and control condition (quiet rest) before consuming a sweet-fat liquid meal (530 Kcal milkshake). Hormonal responses and subjective measures of stress, interoception, and appetite were assessed.

RESULTS

In BN but not HC, desire to binge remained consistently high in both conditions and correlated with perceived hunger. There were no group differences in total ghrelin levels and levels were not influenced by the CPT. Baseline cortisol levels were similar for HC and BN groups, however BN subjects did not demonstrate a CPT-induced elevation in cortisol.

CONCLUSION

HPA axis dysregulation is present in BN, and meal-related total ghrelin does not appear to be involved in the stress response in women with or without BN. Desire to binge is persistent in BN, irrespective of the presence of an acute stressor with sweet-fat meal and may be associated with heightened emotional states in general.

From disordered eating to addiction: the "food drug" in bulimia nervosa

The high prevalence of substance abuse in individuals with bulimia nervosa (BN) and the pervasive symptom substitution in many types of drug addiction suggest that a number of substances--including food--can impair an individual's self-control, even in the presence of negative consequences. Nonetheless, the neurobiological similarities between BN and drug addiction are not clearly established. This review explores how the specific eating patterns seen in BN (binge eating and purging, with intermittent dietary restriction) are particularly addictive and differentiate BN from other eating disorders and obesity. A number of peripheral and central biological aberrations seen in BN may result in altered reward sensitivity in these individuals, particularly through effects on the dopaminergic system. Neurobiological findings support the notion that BN is an addictive disorder, which has treatment implications for therapy and pharmacological manipulations.

Disordered eating behaviour is associated with blunted cortisol and cardiovascular reactions to acute psychological stress

Research suggests a potential dysregulation of the stress response in individuals with bulimia nervosa. This study measured both cardiovascular and cortisol reactions to a standardised laboratory stress task in individuals identified as showing disordered eating behaviour to determine whether dysregulation of the stress response is characteristic of the two branches of the stress response system. Female students (N=455) were screened using two validated eating disorder questionnaires. Twelve women with disordered eating, including self-induced vomiting, and 12 healthy controls were selected for laboratory stress testing. Salivary cortisol and cardiovascular activity, via Doppler imaging and semi-automatic blood pressure monitoring, were measured at resting baseline and during and after exposure to a 10-min mental arithmetic stress task. Compared to controls the disordered eating group showed blunted cortisol, cardiac output, heart rate, and stroke volume reactions to the acute stress, as well as an attenuated vasodilatory reaction. These effects could not be accounted for in terms of group differences in stress task performance, subjective task impact/engagement, age, BMI, neuroticism, cardio-respiratory fitness, or co-morbid exercise dependence. Our findings suggest that disordered eating is characterised by a dysregulation of the autonomic stress-response system. As such, they add further weight to the general contention that blunted stress reactivity is characteristic of a number of maladaptive behaviours and states.

Bulimia nervosa and evidence for striatal dopamine dysregulation: a conceptual review

OBJECTIVE

This article reviews concepts and evidence, based in particular on the work of Bartley G. Hoebel and colleagues, which suggest that a better understanding of the role of striatal dopamine (DA) in the initiation and/or maintenance of bulimia nervosa (BN) may result in a clearer characterization of mechanisms underlying BN.

METHODS

Literature review, using PubMed search.

RESULTS

Several lines of evidence, including the work of Bartley G. Hoebel, implicate the importance of striatal DA in feeding behavior, as well as in the disordered eating behaviors relevant to BN. Preclinical models of 'BN-like' eating behaviors have been associated with changes in striatal DA and DA receptor measures. Emerging clinical research also suggests that striatal DA abnormalities exist in individuals with BN.

CONCLUSION

Alterations in striatal DA may exist in patients with BN. While the precise relationship between these findings and the etiology and maintenance of bulimic symptomatology remains unclear, further investigation of brain DA systems is a fruitful avenue of future research in BN.

Pain experience related to self-injury in eating disorder patients

A reduced pain sensitivity has been found in eating disorder (ED) patients. These patients often show various types of self-injurious behaviors (SIB) which some experience as painful, while others report analgesia during episodes of SIB. How can we explain these differences? We studied female ED patients (N=185) of whom 84 had admitted some form of SIB in their recent history. The presence/absence of pain report during SIB was not significantly related to the type of ED. The longer the history of SIB, the less pain was reported. Ratings of dissociation and traumatic experiences were higher in patients who did not experience pain while injuring themselves. We discuss several biopsychosocial explanations for these findings with suggestions for future research.

Menstrual cycle irregularity in bulimia nervosa. Associated factors and changes with treatment

OBJECTIVES

This study determined the clinical and nutritional variables associated with menstrual disturbance in women with bulimia nervosa (BN).

METHODS

Eighty-two women with DSM-IV BN underwent psychiatric, nutritional and menstrual related assessments prior to an outpatient treatment programme and at 12 months follow-up.

RESULTS

Forty-five percent reported a current irregular menstrual cycle. A high frequency of vomiting, low thyroxine concentrations and low dietary fat intake were independently associated with irregular menses at pretreatment. At 12 months follow-up, 30.5% reported irregular menstrual cycles. A greater difference between past maximum and minimum body weight, smoking and depression were associated with menstrual irregularity at 12 months follow-up. Of those with irregular menstrual cycles at pretreatment, 56.8% became regular at 12 months follow-up.

CONCLUSION

Menstrual irregularity in BN is associated with indices of nutritional restriction that are not reflected by low body weight or energy intake. Depression, cigarette smoking and fluctuations in body weight may act as metabolic stresses that contribute to the perpetuation of menstrual disturbances.

Does binge eating play a role in the self-regulation of moods?

Self-reported emotional experiences and eating behaviors were studied in college students in an attempt to determine what types of emotional experiences precede and follow binge eating and how specific types of compensatory behaviors modify these experiences. First-year male and female students (N=390) were surveyed for depression, anxiety, health status, life satisfaction, and eating attitudes (EAT-26). Those reporting recurrent binge eating episodes were asked to describe their emotional feelings before and after bingeing and before and after compensatory activities. EAT-26 scores corresponding to scores previously reported for eating disordered patients were found in 9.7% of students. Binge eating was nearly twice as frequent among females (16.4%) as males (8.6%). Among females, positive relationships were found between specific EAT-26 factors scores and both anxiety and depression scores. The emotional antecedents and consequences of binge eating and of compensatory activities were compared in three sub-groups of individuals who reported recurrent bingeing with loss of self-control during binges. The three sub-groups consisted of individuals who reported, 1) bingeing without engaging in compensatory activities, 2) bingeing and compensating by means other than vomiting (fasting, exercising, or use of laxatives or diuretics), and 3) bingeing and compensating by vomiting. Regardless of the type of activity, those individuals who engaged in compensatory activities reported greater negative affect preceding binge episodes than those who did not compensate. In addition, contrary to expectations, negative affect did not decrease, but instead increased significantly, following binge episodes and decreased immediately before and after compensatory activities.

Blunted cardiovascular and catecholamine stress reactivity in women with bulimia nervosa

Cardiovascular and catecholamine responses to mental stressors were investigated in women with bulimia nervosa (BN) and in healthy control subjects. Fifteen women with BN and 15 control subjects completed psychosocial questionnaires before laboratory testing, where they were exposed to an interpersonally based speech stressor and a serial math task. Blood pressure, heart rate, epinephrine, norepinephrine and, via impedance cardiography, systolic time intervals, cardiac output and total peripheral resistance were measured at rest and during stress. Results indicated that BN was associated with blunted sympathetic activation in response to mental stress, indicated by increased pre-ejection period responses and blunted systolic blood pressure, heart rate and epinephrine responses. In contrast, women with BN had elevated cortisol levels when compared with control women. In addition, despite equivalent performance between groups, bulimic women reported feeling significantly more confused, frustrated, inadequate and dissatisfied with their performance during tasks. Psychosocial questionnaires also indicated that women with BN perceived more stress, had worse coping skills, lower self-esteem and sense of mastery, reported less social support, had worse mood, had greater anxiety and were more depressed when compared with control women. These results are interpreted as reflecting physiological and psychological profiles indicative of distress vs. active effort coping in BN.

Opioid involvement in feeding behaviour and the pathogenesis of certain eating disorders

Incidental findings from animal experiments involving administration of exogenous opioid agonists indicate that there are close links between the endogenous opioid system and feeding behaviour. Subsequent investigations aimed at elucidating the nature of the opioid-feeding relationship led to a wide variety of findings, some of them apparently contradictory. This paper examines the effects of opioid agonists and antagonists on feeding behaviour, and considers the evidence relating levels of endogenous opioids to feeding states, with particular reference to certain eating disorders, including anorexia nervosa, bulimia nervosa, Prader-Willi syndrome, and eating-induced obesity. The receptors which may be involved in opioid-feeding relationships are discussed. Relationships between the endogenous opioid system and other systems, such as the dopaminergic, noradrenergic and hormonal systems, are considered insofar as they may have bearing on the modulation of feeding behaviour. Finally, three theories are briefly outlined which attempt to link the endogenous opioid system with feeding modulation and the pathogenesis of certain eating disorders. The suggestion is put forward that anorexia nervosa may represent a pathological consequence of the triggering of a primitive mechanism for coping with unforeseen food shortages which may have short-term advantages, e.g., for masking or temporarily alleviating a depressed state.

Pain perception in psychiatric disorders: a review of the literature

Aberrations of pain experience occur frequently in psychiatric disorders and hence pathological alterations in the basic mechanisms underlying pain experience can be expected. Nevertheless, pain perception, as one of the most important basic mechanisms of pain experience, has rarely been assessed experimentally in psychiatric disorders. The authors review the relevant experimental studies on pain perception in patients with anxiety disorders, schizophrenia, depression, eating disorders and personality disorders and suggest lines for future research. Finally, they point out that the experimental study of pain perception is useful not only in understanding aberrant pain experiences in psychiatric disorders but also in elucidating pathophysiological mechanisms because pain perception is controlled by neurochemical and neurohormonal functions known to be affected by psychiatric disease processes.

Pain sensitivity in anorexia nervosa and bulimia nervosa

Pain threshold was measured with short heat stimuli using a contact thermode in 19 patients with anorexia nervosa, 20 patients with bulimia nervosa, and 21 control subjects. Both patient groups had significantly elevated pain thresholds compared with the control subjects. In the total sample, no substantial covariation could be demonstrated among pain threshold and clinical, physiological, metabolic, or psychological data. However, in separate regression analyses pain threshold correlated significantly (negatively) with local skin temperature in the anorectic patients and almost significantly (positively) with body weight in the bulimic patients. This finding suggests that the reduced pain sensitivity in the two kinds of eating disorders might have different causes.