Reward processing in obesity, substance addiction and non‐substance addiction

Abstract

Similarities and differences between obesity and addiction are a prominent topic of ongoing research. We conducted an activation likelihood estimation meta-analysis on 87 studies in order to map the functional magnetic resonance imaging (fMRI) response to reward in participants with obesity, substance addiction and non-substance (or behavioural) addiction, and to identify commonalities and differences between them. Our study confirms the existence of alterations during reward processing in obesity, non-substance addiction and substance addiction. Specifically, participants with obesity or with addictions differed from controls in several brain regions including prefrontal areas, subcortical structures and sensory areas. Additionally, participants with obesity and substance addictions exhibited similar blood-oxygen-level-dependent fMRI hyperactivity in the amygdala and striatum when processing either general rewarding stimuli or the problematic stimuli (food and drug-related stimuli, respectively). We propose that these similarities may be associated with an enhanced focus on reward--especially with regard to food or drug-related stimuli--in obesity and substance addiction. Ultimately, this enhancement of reward processes may facilitate the presence of compulsive-like behaviour in some individuals or under some specific circumstances. We hope that increasing knowledge about the neurobehavioural correlates of obesity and addictions will lead to practical strategies that target the high prevalence of these central public health challenges.

Mexico City normal weight children exposed to high concentrations of ambient PM2.5 show high blood leptin and endothelin-1, vitamin D deficiency, and food reward hormone dysregulation versus low pollution controls. Relevance for obesity and Alzheimer disease

“…Since overeating, particularly of highly palatable foods, can affect the dopaminergic and opioidergic brain systems, the development of addiction-like behavior has to be considered (Daws et al, 2011). The issue is critical in urban youngsters because the behavioral and neurochemical overlap between overeating highly palatable foods, alcohol and cocaine drug addiction, insulin signaling and regulation of dopamine neurotransmission (Daws et al, 2011;Murray et al, 2014;Engel and Jerlhag, 2014;Blum et al, 2014;García-García et al, 2014;Burghardt et al, 2012). The Reward Deficiency Syndrome (RDS) results from an impairment of the brain reward circuitry with a hypo-dopaminergic function (Blum et al, 2014).…”

Slave to habit? Obesity is associated with decreased behavioural sensitivity to reward devaluation

“…In rodent studies, it has been demonstrated that drug-naïve high impulsive individuals are more likely to engage in drug self-administration than their low impulsive littermates (Dalley et al, 2007). Interestingly, drug dependency shares several similarities with obesity (García-García et al, 2014;see Volkow et al, 2013, for a review). Thus, a tendency to unpremeditated behaviour might also be a precursor of the transition from goal-directed (reward-driven) to habit-like (stimulus-driven) food consumption.…”

Functional network centrality in obesity: A resting-state and task fMRI study

“…Additionally, functional neuroimaging studies have observed differences between participants with obesity and normal-weight controls during reward processing. In response to food stimuli, participants with obesity exhibited higher activation of the parahippocampal gyrus/amygdala, putamen and superior frontal gyrus, along with lower activation of the insula and occipital areas (Nummenmaa et al, 2012;Brooks Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/psychresns García-García et al, 2014). To summarize, relative to normal-weight controls, participants with obesity seem to present a widely distributed pattern of structural and functional brain differences.…”