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The meta-analysis provides strong support that inefficient set-shifting is a salient neuropsychological phenomenon across ED subtypes and obesity, but is less prominent in AN/BP and overweight. Compulsivity seems to be a common underlying factor supporting a dimensional and transdiagnostic conceptualization of EDs and obesity.

The aim of this meta-analysis was to summarise data from neuropsychological studies on inhibitory control to general and disease-salient (i.e., food/eating, body/shape) stimuli in bulimic-type eating disorders (EDs). A systematic literature search was conducted to identify eligible experimental studies. The outcome measures studied included the performance on established inhibitory control tasks in bulimic-type EDs. Effect sizes (Hedges' g) were pooled using random-effects models. For inhibitory control to general stimuli, 24 studies were included with a total of 563 bulimic-type ED patients: 439 had bulimia nervosa (BN), 42 had anorexia nervosa of the binge/purge subtype (AN-b), and 82 had binge eating disorder (BED). With respect to inhibitory control to disease-salient stimuli, 12 studies were included, representing a total of 218 BN patients. A meta-analysis of these studies showed decreased inhibitory control to general stimuli in bulimic-type EDs (g = −0.32). Subgroup analysis revealed impairments with a large effect in the AN-b group (g = −0.91), impairments with a small effect in the BN group (g = −0.26), and a non-significant effect in the BED group (g = −0.16). Greater impairments in inhibitory control were observed in BN patients when confronted with disease-salient stimuli (food/eating: g = −0.67; body/shape: g = −0.61). In conclusion, bulimic-type EDs showed impairments in inhibitory control to general stimuli with a small effect size. There was a significantly larger impairment in inhibitory control to disease salient stimuli observed in BN patients, constituting a medium effect size.

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BN but not BED patients differed from their respective control groups concerning the "stopping" component of impulsivity. These differences in motor inhibition may contribute to the behavioral distinctions in binge-eating behavior between BN and BED.

Clinical observations and similarities to addiction suggest heightened reward sensitivity to food in patients with bulimictype eating (BTE) disorders. Therefore, we investigated the expectation and receipt of food reward compared with monetary reward in patients with BTE. Fifty-six patients with BTE (27 patients with binge eating disorder and 29 with bulimia nervosa) and 55 matched healthy control participants underwent event-related functional magnetic resonance imaging while performing both food and monetary incentive delay tasks. BTE patients exhibited reduced brain activation in the posterior cingulate cortex during the expectation of food and increased activity in the medial orbitofrontal cortex, anterior medial prefrontal cortex and posterior cingulate cortex during the receipt of food reward. These findings were relevant to food because we found no significant group differences related to monetary reward. In the patients, higher brain activity in the medial orbitofrontal cortex during the receipt of food reward was related to higher levels of trait food craving and external eating. BTE patients exhibited increased hedonic processing during the receipt of food reward. These findings corroborate the notion that an altered responsiveness of the reward network to food stimuli is associated with BTE.

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IntroductionThe consumption of food is necessary for our everyday survival and is promoted by an intricate network of complex homeostatic and hedonic interactions. Hunger is a motivational state considered as an endpoint of these elements; it ensures that we actively seek out food when necessary. However, hunger is not only the result of simple energy deficiency; it has emerged as a product of a complex biopsychological and environmental interaction. Given the rapid development of obesity worldwide, a better understanding of the interaction between the encoding of food in the brain reward network and homeostatic energy regulation is of paramount importance for the development of new treatment strategies. BACKGROUND.Food intake is guided by homeostatic needs and by the reward value of food, yet the exact relation between the two remains unclear. The aim of this study was to investigate the influence of different metabolic states and hormonal satiety signaling on responses in neural reward networks.