Barbara E. Wolfe

Validity and utility of the current definition of binge eating.

OBJECTIVE Binge eating, a cardinal symptom of bulimia nervosa (BN) and binge eating disorder (BED), continues to pose challenges in terms of its definition and thus construct validity and clinical utility. This article reviews the available empirical data that support or refute the current DSM-IV-TR defined characteristics of a binge episode. METHOD A systematic literature review was conducted using Medline/PubMed electronic database on DSM-IV-TR defined binge characteristics and associated attributes. RESULTS Data support the current DSM guidelines indicating that binge episodes typically occur in less than 2 h. Size of binge episodes has variability across BN and BED diagnostic groups. Loss of control (LOC) continues to be a core feature of binge eating. Negative affect is the most widely reported antecedent. Strikingly, little is known about binge episodes among individuals with anorexia nervosa-binge/purge subtype. DISCUSSION Available empirical evidence supports the current DSM duration and LOC attributes of a binge episode in BN and BED. However, a more controversial issues is the extent to which size is important in the definition of a binge episode (e.g., subjective vs. objective episodes) across diagnostic categories and the extent to which binge size informs prognosis, treatment, and clinical outcomes. Further study of binge eating attributes in AN is needed.

Effect of dieting on plasma leptin, soluble leptin receptor, adiponectin and resistin levels in healthy volunteers

objective  Recent findings demonstrating important effects of the adipokines on metabolism, energy homeostasis and body weight regulation have prompted research on the possible role of negative energy balance in altering adipocytokine regulation. The goal of this study was to evaluate the effects of a hypocaloric diet in healthy normal‐weight volunteers. An additional goal was to help clarify the contribution of restricted caloric intake to altered plasma adipokine levels in the eating disorders anorexia nervosa and bulimia nervosa.

Alexithymia ratings in bulimia nervosa : clinical correlates

&NA; Previous reports indicate that some patients with eating disorders have alexithymic characteristics, including affect deficit states and paucity of imagination. This study evaluated whether nonhospitalized patients with bulimia nervosa had elevated ratings of alexithymia in comparison to age‐matched controls, and whether severity of bulimic symptoms was correlated with elevations in alexithymia ratings. Because alexithymia may be secondary to concurrent depression, this study was limited to patients with bulimia nervosa who were free of major depression. The authors compared alexithymia ratings for nonhospitalized normal weight women meeting DSM‐III‐R criteria for bulimia nervosa (N = 20) to healthy female volunteers (N = 20), utilizing the Toronto Alexithymia Scale (TAS) as the primary assessment instrument. Subjects also completed standardized rating scales for bulimic symptoms, depression, and anxiety. Alexithymia rating scale scores were significantly higher for patients with bulimia nervosa than for controls. In comparison to controls, patients had significant elevations on TAS factors reflecting affect deficit states, but normal scores for factors reflecting imagination and abstract thinking. Frequency of binge eating or purging behaviors was not correlated with alexithymia ratings. These data indicate that some patients with bulimia nervosa have alexithymic characteristics. Affect dysregulation was more prominent than limitation in fantasy or metaphorical thought. Additional studies are needed to assess whether presence of alexithymic characteristics may be predictive of response to treatment in patients with bulimia nervosa.

Hypnotizability, dissociation, and bulimia nervosa

This study examined the levels of hypnotizability and dissociation in an outpatient sample of 17 normal-weight bulimic women and 20 healthy controls. Bulimic patients were significantly more hypnotizable than controls (p < .003) and scored higher on a self-report scale of dissociative experiences (p < .02). The results of measures of hypnotizability and dissociation showed a significant positive correlation in the combined subject group. These results are consistent with previous reports on hospitalized patients and college students and suggest that psychological factors associated with hypnotizability might play a role in the etiology and treatment of bulimia nervosa.

MEDICATIONS IN THE TREATMENT OF EATING DISORDERS

Effective planning for medication treatment in patients with bulimia nervosa and anorexia nervosa is based on a comprehensive clinical assessment, including a careful review of comorbid psychiatric disorders and response to treatments for previous episodes of the disorder. Although most patients with bulimia nervosa are offered a trial of psychotherapy, significant results of controlled trials have contributed to an increased role for medications in the treatment of patients with this disorder. Pharmacologic treatment of anorexia nervosa has similarities to that of treatment-resistant depression, with the clinician turning to open trials and clinical reports for clues to rational management. As described in this article, considerations of potential side effects and medical complications are likely to play an important role in guiding the choice of medication used for treatment of patients with eating disorders.

Co-morbidity and disorder-related distress and impairment in purging disorder

BACKGROUND Recent studies suggest that purging disorder (PD) may be a common eating disorder that is associated with clinically significant levels of distress and high levels of psychiatric co-morbidity. However, no study has established evidence of disorder-related impairment or whether distress is specifically related to PD rather than to co-morbid disorders. METHOD Three groups of normal-weight women [non-eating disorder controls (n=38), with PD (n=24), and with bulimia nervosa (BN)-purging subtype (n=57)] completed structured clinical interviews and self-report assessments. RESULTS Both PD and BN were associated with significant co-morbidity and elevations on indicators of distress and impairment compared to controls. Compared to BN, PD was associated with lower rates of current and lifetime mood disorders but higher rates of current anxiety disorders. Elevated distress and impairment were maintained in PD and BN after controlling for Axis I and Axis II disorders. CONCLUSIONS PD is associated with elevated distress and impairment and should be considered for inclusion as a provisional disorder in nosological schemes such as the Diagnostic and Statistical Manual to facilitate much-needed research on this clinically significant syndrome.

Serotonin Function Following Remission from Bulimia Nervosa

Abnormal serotonergic regulation in bulimia nervosa is thought to contribute to recurrent binge eating, depressed mood, and impulsivity. To follow-up on previous studies showing decreased neuroendocrine responses in symptomatic patients, this study assessed serotonin-mediated prolactin responses in individuals who had remitted from bulimia nervosa. Subjects included 21 women with a history of bulimia nervosa and 21 healthy female controls, as well as an additional comparison group of 19 women with current bulimia nervosa. Placebo-controlled neuroendocrine response studies utilized a single oral dose (60 mg) of the indirect serotonin agonist d,l-fenfluramine. For the bulimia nervosa remitted group, the fenfluramine-stimulated elevation in serum prolactin concentration was not significantly different from the response in healthy controls, but was significantly larger than the response in patients with current bulimia nervosa (p < .01). These findings suggest that diminished serotonergic neuroendocrine responsiveness in bulimia nervosa reflects a state-related abnormality. The results are discussed in relationship to recent reports indicating that some alterations in central nervous system serotonin regulation may persist in symptomatically recovered individuals.

Elevated sweet taste pleasantness ratings in bulimia nervosa

Recent studies suggest that some patients with bulimia nervosa may experience elevated pleasantness responses to sweet taste. This study explored possible associations between symptoms patterns and pleasantness ratings for sucrose solutions in bulimic patients. Subjects included 15 women meeting DSM III-R criteria for narrowly defined bulimia nervosa (no history of other eating disorder); five patients with current bulimia nervosa and a past history of anorexia nervosa; and 20 healthy age-matched female controls. Subjects ate a standardized breakfast prior to the morning study visit. Sucrose-water solutions (0% to 40% sucrose) were rated for sweetness intensity and pleasantness. Patients with narrowly defined bulimia nervosa showed significantly higher pleasantness ratings for 40% sucrose solutions than controls and patients with a history of anorexia nervosa. Pleasantness ratings were not significantly correlated with frequency of binge eating or purging behaviors. These results extend previous evidence for altered sweet taste pleasantness responses in bulimia nervosa, and for differences in eating-related behaviors between patients with narrowly defined bulimia nervosa vs. those with past anorexia nervosa.

Neuropeptides in Eating Disorders

The past decade has witnessed a dramatic acceleration in research on the role of the neuropeptides in the regulation of eating behavior and body weight homeostasis. This expanding research focus has been driven in part by increasing public health concerns related to obesity and the eating disorders anorexia nervosa (AN) and bulimia nervosa (BN). Preclinical advances have been facilitated by the development of new molecular and behavioral research methodologies. With a focus on clinical investigations in AN and BN, this article reviews research on selected hypothalamic and gut-related peptide systems with prominent effects on eating behavior. Studies of the orexigenic peptides neuropeptide Y and the opioid peptides have shown state-related abnormalities in patients with eating disorders. With respect to gut-related peptides, there appears to be substantial evidence for blunting in the meal-related release of the satiety promoting peptide cholecystokinin in BN. Fasting plasma levels of the orexigenic peptide ghrelin have been found to be elevated in patients with AN. As discussed in this review, additional studies will be needed to assess the role of nutritional and body weight changes in neuropeptide alterations observed in symptomatic eating disorder patients, and to identify stable trait-related abnormalities in neuropeptide regulation that persist in individuals who have recovered from an eating disorder.

Comparison of the effects of amino acid mixture and placebo on plasma tryptophan to large neutral amino acid ratio.

To assess the possible role of altered central serotonin function in psychiatric disorders, investigators have utilized pharmacological challenge testing with an amino acid mixture to decrease blood tryptophan concentration and, indirectly, brain serotonin levels. The aim of this pilot study was to assess the effectiveness of a modified amino mixture, administered in capsule form, in decreasing plasma tryptophan levels. Studies were conducted in six healthy, medication-free female volunteers. Following double-blind, randomized, cross-over design, subjects received on separate days capsules containing a tryptophan-free amino acid mixture (31.5 grams) or lactose placebo. Over the six hours following amino acid administration, plasma tryptophan concentrations decreased to 21% of baseline values, while the tryptophan/large neutral amino acid ratio decreased to 6% of baseline. Subjects reported minimal symptoms of nausea or other side effects following amino acid administration. The results suggest that the modified amino acid mixture may be useful in assessing behavioral responses to acute tryptophan depletion challenge testing.