The neurobiological reward system and binge eating: A critical systematic review of neuroimaging studies

Abstract

Objective Changes in reward processing are hypothesized to play a role in the onset and maintenance of binge eating (BE). However, despite an increasing number of studies investigating the neurobiological reward system in individuals who binge eat, no comprehensive systematic review exists on this topic. Therefore, this review has the following objectives: (1) identify structural and functional changes in the brain reward system, either during rest or while performing a task; and (2) formulate directions for future research. Methods A search was conducted of articles published until March 31, 2022. Neuroimaging studies were eligible if they wanted to study the reward system and included a group of individuals who binge eat together with a comparator group. Their results were summarized in a narrative synthesis. Results A total of 58 articles were included. At rest, individuals who binge eat displayed a lower striatal dopamine release, a change in the volume of the striatum, frontal cortex, and insula, as well as a lower frontostriatal connectivity. While performing a task, there was a higher activity of the brain reward system when anticipating or receiving food, more model‐free reinforcement learning, and more habitual behavior. Most studies only included one patient group, used general reward‐related measures, and did not evaluate the impact of comorbidities, illness duration, race, or sex. Discussion Confirming previous hypotheses, this review finds structural and functional changes in the neurobiological reward system in BE. Future studies should compare disorders, use measures that are specific to BE, and investigate the impact of confounding factors. Public Significance Statement This systematic review finds that individuals who binge eat display structural and functional changes in the brain reward system. These changes could be related to a higher sensitivity to food, relying more on previous experiences when making decisions, and more habitual behavior. Future studies should use a task that is specific to binge eating, look across different patient groups, and investigate the impact of comorbidities, illness duration, race, and sex.

The effect of stress on delay discounting in bulimia nervosa and alcohol use disorder: a functional magnetic resonance imaging study.

“…Future studies should aim to replicate the findings in other samples. Fifth, like most studies investigating the neurobiological reward system in BE and BD, this study looks at voxel-wise brain activity (60).…”

“…This study also has several strengths. In contrast to most studies investigating the reward system in BE and BD, it not only uses monetary rewards, but also food and alcohol (60). Furthermore, it is the first study to investigate DD in both patients with BN and AUD.…”

The interplay between prolactin and cardiovascular disease

“…Dopaminergic neurons project from the ventral tegmental area (VTA) to the nucleus accumbens and participate in the regulation of the brain reward pathway ( 123 , 124 ). Several studies point to the role of dopamine in the development and maintenance of diet-induced obesity ( 125 ). Also observed in obesity, chronic low-grade inflammation can disturb dopamine tone, which can result in the inability to put in the effort required to achieve the desired goal ( 123 ).…”

5-HT2C Receptor Stimulation in Obesity Treatment: Orthosteric Agonists vs. Allosteric Modulators

“…Food intake is also regulated by the reward brain system (the mesocorticolimbic pathway) structures, such as the ventral tegmental area, nucleus accumbens, prefrontal cortex, hippocampus, and amygdala [ 22 , 23 ]. Changes in reward processing are hypothesized to play a crucial role in the onset and maintenance of binge eating.…”