Combined dieting and stress evoke exaggerated responses to opioids in binge-eating rats.

The authors developed an animal model of binge eating where history of caloric restriction with footshock stress (R + S) causes rats to consume twice the normal amount of palatable food. The authors tested the hypothesis that binge eating is mediated by changes in opioid control of feeding by comparing rats' anorectic and orexigenic responses to naloxone and butorphanol, respectively, and by testing the ability of butorphanol to elicit binge eating of chow when palatable food was absent. Mu/kappa opioid-receptor blockade and activation had exaggerated responses in the R + S rats with naloxone suppressing binge eating to control levels, and although butorphanol did not trigger chow binge eating, it enhanced binge eating of palatable food. These responses in sated normal-weight rats strengthen evidence that reward, over metabolic need, drives binge eating. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Prevalence of gastrointestinal symptoms in obese and normal weight binge eaters

OBJECTIVES: Disturbances in gastrointestinal function may result from disordered eating and may lead to increases in gastrointestinal (GI) symptoms. We compared GI symptoms in obese and non-obese binge eaters and non-binge eaters. METHODS: One hundred nineteen obese and 77 normal-weight females completed a questionnaire on bowel symptoms and binge eating behaviors for the previous 3 months. Based on binge behaviors and body mass index (> 30 kg/m2), individuals were grouped as obese binge eaters (n = 73), obese non-binge eaters (n = 43), non-obese binge eaters (n = 14), and normal-weight controls (n = 61). RESULTS: Obese binge eaters reported more upper GI symptoms than normal controls or obese non-binge eaters (p < 0.001). Compared with normal controls, nausea, vomiting, and bloating was 2-4 times more prevalent in both binge eating groups. Indigestion was more prevalent in both obese groups. Obese binge eaters reported more lower GI symptoms than normal-weight controls (p < 0.05). Binge eating in both weight groups was associated with more frequent abdominal pain and dyschezia. Obesity was associated with more frequent constipation, diarrhea, straining, and flatus, whether or not subjects reported binge eating. Chi-square showed a significant association between obesity, binge eating, and symptoms of irritable bowel syndrome, using the Manning criteria. CONCLUSIONS: Specific GI symptoms were associated with binge eating and obesity. Overall, symptoms were more prevalent and more severe in obese binge eaters. The high prevalence of GI symptoms in obese patients who indulge in binge eating should be considered in their evaluation and treatment.     

Examining the addictive-like properties of binge eating using an animal model of sugar dependence.

The increase in the incidence of obesity and eating disorders has encouraged research efforts aimed at understanding the etiology of abnormal eating behaviors. Clinical reports have led to the suggestion that some individuals may develop addictive-like behaviors when consuming palatable foods. Binge eating is a behavioral component of bulimia and obesity and has also become increasingly common in nonclinical populations in our society. This review summarizes the behavioral and neurochemical similarities between binge eating of palatable foods and the administration of drugs of abuse. An animal model of bingeing on sugar is used to illustrate behaviors found with some drugs of abuse, such as opiate-like withdrawal signs, enhanced intake following abstinence, and cross-sensitization. Related neurochemical changes commonly observed with drugs of abuse, including changes in dopamine and acetylcholine release in the nucleus accumbens, can also be found with bingeing on sugar. These neurochemical alterations are exacerbated when animals binge on sugar while at a low body weight or when the food they ingest is purged. Drawing on other animal models and the clinical literature, parallels between drug abuse and binge-eating behavior are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Bulimia and binge eating in college women: A comparison of personality and behavioral characteristics.

Assessed 9 behavioral and personality characteristics—restraint, binge eating, high self-expectations, demand for approval, body attitude, assertion, dating, self-esteem, and depression—that have been implicated in studying the onset of bulimia. Ss were 30 women who fulfilled an operationalized definition of the DSM-III criteria for bulimia (bulimics), 22 women who reported binge eating 8 or more times per month but did not fulfill the criteria for bulimia (binge eaters), and 28 women who did not binge eat (controls). Ss completed measures that included the Beck Depression Inventory, a self-esteem index, and the short form of the Personality Attributes Questionnaire. In comparison to controls, bulimics were more depressed and had lower self-esteem, poorer body image, higher self-expectations, higher need for approval, greater restraint, and higher binge-eating scores. Binge eaters exhibited higher restraint and binge-eating scores than controls. Bulimics and binge eaters differed significantly on all but a few variables. Results suggest that treatment for bulimics should extend beyond the disturbed eating pattern and that the distinction between binge eating and bulimia is an important one. Some empirical support for the DSM-III definition of bulimia was found. (31 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Frontal brain asymmetry in restrained eaters.

It is well known that the eating patterns that restrain chronic dieters (restrained eaters) can be disinhibited by anxiety, which in turn has been associated with relative right frontal brain activity in independent electroencephalographic (EEG) studies. Combining these two lines of evidence, the authors tested the hypothesis that chronic restrained eating is associated with relative right frontal asymmetry. Resting anterior brain asymmetry and self-reported measures of anxiety and depression were collected in 23 restrained and 32 unrestrained eaters. As hypothesized, groups differed in tonic frontal activity, with restrained eaters showing more relative right frontal activity. Furthermore, relative right frontal activity was associated with greater self-reported restraint. Right-sided prefrontal asymmetry may thus represent a diathesis associated with increased vulnerability toward restrained eating. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of anxiety on eating: Does palatability moderate distress-induced overeating in dieters?

When confronted with an anxiety-producing threat to self-esteem, restrained eaters (dieters) increase their food consumption. The functional explanation suggests that increased eating temporarily counteracts or masks dysphoria for the restrained eater; externality or stimulus sensitivity theories propose that distress shifts the dieter's attention to external stimulus properties (e.g., taste) and to activities stimulated by such external cues. In an attempt to distinguish between these two explanations, anxious and nonanxious restrained and unrestrained eaters were given palatable and unpalatable foods, and consumption was measured. Results support the functional explanations: Distressed dieters increased their intake of food regardless of taste properties. Theoretical and practical implications for both restrained eating and the behavior of eating disorder patients are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Eating behavior of bulimics, self-identified binge eaters, and non-eating-disordered individuals: what differentiates these populations?

This article reviews and critiques the eating behavior literature comparing the binge and non-binge-eating episodes of three populations of normal-weight women: bulimics, self-identified binge eaters, and non-eating-disordered women. The specific behaviors evaluated are number of calories consumed during different types of eating episodes, frequency of binge eating, number of eating episodes, rate of food consumption, the macronutrient composition of the food ingested, and context and duration of eating. Differences in these populations' eating behavior are analyzed in terms of their theoretical contribution. It is concluded that differences in the observed behavior of these groups are consistent with restraint theory, purge opportunity, and the forbidden foods hypothesis. Conversely, results do not support carbohydrate craving theory or a deficit in the satiety mechanisms of bulimics. Suggestions for future research are presented.     

Effects of plans for future meals on counterregulatory eating by restrained and unrestrained eaters.

Hypothesized that the counterregulatory eating of restrained eaters would be exacerbated by a high-calorie meal plan but prevented by a low-calorie meal plan and that unrestrained eaters would follow the reverse pattern. In Exp I, 33 restrained- and 33 unrestrained-eating female undergraduates consumed a milkshake preload and then taste-tested nuts. Prior to the taste test, Ss were led to believe that they would be returning to the laboratory at dinner-time to consume a rich, high-calorie dinner, a low-calorie dinner, or to participate in a noneating-related experiment (control condition). Results show that high-calorie manipulation increased consumption by both restrained and unrestrained eaters. In Exp II, a very low-calorie condition was added and ice cream was substituted for nuts as the taste-test food; 48 restrained and 48 unrestrained female undergraduates participated. Results confirm the findings of Exp I. It is concluded that (1) the restraint dimension was more continuous than dichotomous, with unrestrained Ss evidencing a higher threshold for counterregulation; and (2) tasting sweet palatable foods may reduce the ability of certain cognitive factors to affect counterregulatory eating by restrained eaters. (49 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Group cognitive-behavioral treatment for the nonpurging bulimic: An initial evaluation.

This study tested the initial effects of cognitive-behavioral therapy for binge eating in Ss who do not purge. Forty-four female binge eaters were randomized to either cognitive-behavioral treatment (CB) or a waiting-list (WL) control. Treatment was administered in small groups that met for 10 weekly sessions. At posttreatment a significant difference was found, with 79% of CB Ss reporting abstinence from binge eating and a 94% decrease in binge eating compared with a nonsignificant reduction (9%) in binge eating and zero abstinence rate in WL Ss. Following the posttest assessment, WL Ss were treated and evidenced an 85% reduction in binge episodes and a 73% abstinence rate. Binge eating significantly increased at 10-week follow-up for initially treated Ss; however, the frequency remained significantly improved compared with baseline levels. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Binge eating proneness emerges during puberty in female rats: A longitudinal study.

Puberty is a critical risk period for binge eating and eating disorders characterized by binge eating. Previous research focused almost entirely on psychosocial risk factors during puberty to the relative exclusion of biological influences. The current study addressed this gap by examining the emergence of binge eating during puberty in a rat model. We predicted that there would be minimal differences in binge eating proneness during pre-early puberty, but significant differences would emerge during puberty. Two independent samples of female Sprague–Dawley rats (n = 30 and n = 36) were followed longitudinally across pre-early puberty, mid-late puberty, and adulthood. Binge eating proneness was defined using the binge eating resistant (BER)/binge eating prone (BEP) model of binge eating that identifies BER and BEP rats in adulthood. Across two samples of rats, binge eating proneness emerged during puberty. Mixed linear models showed little difference in palatable food intake between BER and BEP rats during pre-early puberty, but significant group differences emerged during mid-late puberty and adulthood. Group differences could not be accounted for by changes in nonpalatable food intake or body weight. Similar to patterns in humans, individual differences in binge eating emerge during puberty in female rats. These findings provide strong confirming evidence for the importance of biological risk factors in developmental trajectories of binge eating risk across adolescence. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Central mediation of naloxone-induced anorexia in the ventral tegmental area.

Central naloxone injections were used to show that endogenous opioids in the ventral tegmental area (VTA) regulate consumption of palatable foods. Peripheral injections of naloxone were more effective in reducing the consumption of a sweet solution in normally fed rats than in animals maintained at 85% of their free-feeding body weight. A dose of 10 μg/side naloxone injected into the VTA reduced consumption in normally fed rats, whereas a dose of 25 μg/side did the same in food-restricted animals. The inactive isomer, (+) naloxone, did not reduce consumption; the effect has anatomical specificity. Naloxone effectively decreases the eating of palatable foods, but not eating for survival. This has important implications for the use of opioid antagonists in weight-loss programs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Binge eating onset in obese patients with binge eating disorder

In this study we examined whether obese women with binge eating disorder (BED) reporting earlier onset binge eating differed from those with later onset binge eating on salient clinical parameters. Subjects were 112 women who sought treatment for BED. Subjects with early (< or = age 18) and later onset (> age 18) did not differ in age, weight, body mass index, or severity of binge eating. Participants were interviewed using the Eating Disorder Examination (EDE) and the Structured Clinical Interview for DSM-III-R, and completed a weight and diet history questionnaire. Early-onset binge eaters were more likely than those with later-onset to binge-eat before dieting, to have early onset of obesity and dieting, to have longer binge-free periods, and more paternal obesity and binge eating. Early-onset binge eaters also reported more eating-disorders psychopathology, and they were more likely to report a lifetime history of bulimia nervosa and DSM-III-R mood disorder. These data suggest that there are marked differences among BED patients presenting for treatment. Further research is needed to determine whether these differences reflect a different etiology or have implications for treatment.     

Autoregulatory vasodilation of parenchymal vessels is impaired during cerebral vasospasm

OBJECTIVE: A recent study (Arnow, Kenardy, & Agras, 1995, Journal of Behavioral Medicine, 15, 155-170) has reported on the development and preliminary validation of the Emotional Eating Scale (EES), a questionnaire measure of the tendency to eat in response to affective state. The EES showed high levels of validity among obese binge eaters, but there was no attempt to validate the measure among nonclinical groups. The present study assessed the validity of the EES among nonclinical women, in order to determine whether or not emotional eating is related to unhealthy eating characteristics among the general population. METHODS: The participants were 51 women with no current or past eating disorder. Each completed the EES and the Eating Disorders Inventory (EDI). Validity of the EES was tested using measures of internal consistency and correlations with EDI scales. RESULTS: The EES scales showed a high level of internal consistency and specific associations with EDI scales (particularly Bulimia, Ineffectiveness, and Interpersonal Distrust). The normative scores for this population were substantially lower than among binge eaters, but similar to those found among other clinical groups. CONCLUSIONS: The EES has good levels of validity. It demonstrates that emotional eating is related to bulimic eating attitudes in the broader population, although issues of causality need to be considered. The EES may have a role in the early identification of eating problems in nonclinical groups. Its utility with other eating-disordered groups remains to be established, but there are potential roles in the targeting and evaluation of treatment.     

Motivational enhancement therapy and self-help treatment for binge eaters.

The aims of this study were to evaluate whether a single session of motivational enhancement therapy (MET) would increase participant readiness to change, improve the efficacy of self-help treatment for binge eaters, and improve participant compliance with the self-help manual. Method: Participants with bulimia nervosa or binge eating disorder were randomly assigned either to attend a 1-hr MET session prior to receiving the self-help manual (n = 45) or to receive the self-help manual only (n = 45). Participants were followed for 4 months for assessment of self-reported eating disorder outcome and compliance. Results: The MET intervention resulted in increased readiness to change for binge eating compared with the self-help-only (SH) condition. Few differences were found between the MET condition and the SH condition for changes in eating attitudes and frequency of binge eating and compensatory behaviors. No significant effects were found for compliance. Discussion: This research adds to the literature regarding the use of brief motivational interventions to enhance readiness for change in populations with eating disorders. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Predicting distress-induced eating with self-reports: Mission impossible or a piece of cake?

Comments on the original article, "Assessing yourself as an emotional eater: Mission impossible?" by C. Evers, D. T. D. de Ridder, and M. A. Adriaanse (see record 2009-20990-009). Results of a functional MRI study (Bohon, Stice, & Spoor, 2009) contradict the assertion that it is "impossible" to self-assess emotional eating because the self-report emotional eating scale of the Dutch Eating Behavior Questionnaire (DEBQ-em) predicted important individual differences in reward response during negative moods. Evers et al advance their argument in the context of results of four experiments where self-reported “emotional eaters” (DEBQ-em) did not eat more food during emotional encounters as compared to control conditions or “no emotional eaters.” However, the core characteristic of emotional eaters is not that they eat so much during distress (though binge eaters may do), but that they do not show the typical stress response of eating less (the typical stress response being loss of appetite because of physiological effects that mimic satiety) (Gold & Chrousos, 2002). Accordingly, the moderator effect of emotional eating during distress would be that. “No emotional eaters” eat less and “emotional eaters” eat the same or more compared to control conditions. Close inspection of the results of Evers et al reveals that their “no emotional eaters” did not show the typical stress response of eating less. This opens the possibility that the null findings of Evers et al may be simply explained by misclassification of “no emotional eaters” versus “emotional eaters” because of their use of median splits (a procedure notorious for possible misclassification of subjects into distinct groups). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stereoscopic discrimination of interval and ordinal depth relations on smooth surfaces and in empty space

In the present article, a learning model of binge eating is presented. It has been hypothesized that, parallel to drug intake, the craving and excessive food intake of binge eaters is cue controlled. Research in support of the model is reviewed and a series of predictions about clinical and non-clinical issues is derived from the model. Amongst other things, the model predicts that binge eating might be successfully treated with cue exposure and response prevention. Practical issues are discussed and preliminary pilot studies on cue exposure for bingers are reviewed.     

Obese binge eaters: Affect, cognitions, and response to behavioral weight control.

The present study compared obese female binge eaters and nonbinge eaters of comparable age and weight on mood, diet behavior, and responses to a standard versus modified behavioral weight-control program. The modified behavioral program emphasized meal regularity, intake of complex carbohydrates, and activity as an alternate to overeating. Binge eaters reported significantly more depressive symptomatology, psychological distress, and maladaptive diet behavior than nonbinge eaters at pretreatment and at all subsequent assessments. Furthermore, binge eaters were more likely to drop out of treatment. No differences in weight loss at posttreatment occurred between binge eaters and nonbinge eaters, but binge eaters regained significantly more weight than nonbinge eaters at 6-month follow-up. Differences in weight loss between the groups were not significant at the 1-year follow-up, and no significant differences between the standard and modified treatment conditions were observed. Marked differences between binge eaters and nonbinge eaters in affect and cognitions appeared to persist despite behavioral treatment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hypersensitivity to social interactions in bulimic syndromes: Relationship to binge eating.

This study used a 6- to 22-day experience-sampling procedure to test for hypersensitivity to social interactions in bulimic individuals. Ratings on daily social interactions, self-concepts, moods, and eating behaviors from 55 actively bulimic, 18 formerly bulimic, and 31 noneating-disordered women were obtained. Hierarchical linear modeling analyses showed negative social interactions to be associated with significant increases in self-criticism (SC) and deteriorations in mood in all participants. However, bulimic participants (active or in remission) showed larger increases in SC following negative social interactions than did normal eaters (and thus seemed to be hypersensitive to interpersonal experiences). Additional analyses indicated that binge episodes tended to be preceded by poorer than average social experiences, self-concepts, and moods and followed by deteriorations in self-concept, mood, and social perception. The authors discuss possible perpetuating influences of interpersonal sensitivity in bulimic syndromes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Don't mind if I do: Disinhibited eating under cognitive load.

Past research has shown that strong emotional or motivational states can cause normally restrained eaters to overeat. In this article it is argued that simple cognitive load can also disinhibit eating by restrained eaters. Two studies examined this disinhibition effect. In Study 1, restrained and unrestrained eaters were given the opportunity to consume high-calorie food while performing either a high cognitive-load or low cognitive-load task. Restrained eaters consumed more food when under high cognitive load than when under low cognitive load; unrestrained eaters showed the opposite pattern. Study 2 replicated the disinhibition effect and ruled out stress, diminished awareness of food consumption, and ironic rebound as probable mediators. Results suggest that cognitive load may disinhibit consumption by preventing restrained eaters from monitoring the dietary consequences of their eating behavior. Implications for theories of self-regulation are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Prefrontal and striatal dopamine metabolism during enhanced rebound hyperphagia induced by space restriction--a rat model of binge eating

BACKGROUND: Several lines of evidence indicate that abnormalities in brain dopamine and serotonin metabolism may play an important role in bulimia nervosa. However, the regional neurochemical mechanism of the binge eating is poorly understood. Our purpose was to elucidate brain neurochemical mechanisms of binge eating using a rat model. METHODS: The dopamine release and metabolism in the prefrontal cortex (PFC) and in the ventrolateral striatum (VLS) of rats were studied using microdialysis during enhanced rebound hyperphagia induced by space restriction (an animal model of binge eating). RESULTS: The rats showed rebound hyperphagic state when they were released from scheduled feeding (2 hours/day feeding for 7 days). The hyperphagia was further enhanced when they were put in a space-restricted cage where their mobility was restricted. Dopamine release and metabolism were increased both in the PFC and in the VLS during the enhanced rebound hyperphagia. CONCLUSIONS: These results tentatively suggest that increased dopamine release and metabolism in the PFC and in the VLS may be related to space restriction and to activation of motor function involved in feeding behavior, respectively. The enhanced rebound hyperphagia induced by space restriction may be useful as an animal model of binge eating.