Overlapping Neural Endophenotypes in Addiction and Obesity

Abstract

Impulsivity refers to a tendency to act rapidly without full consideration of consequences. The trait is thought to result from the interaction between high arousal responses to potential rewards and poor self-control. Studies have suggested that impulsivity confers vulnerability to both addiction and obesity. However, results in this area are unclear, perhaps due to the high phenotypic complexity of addictions and obesity. Focusing on impulsivity, the aim of this review is to tackle the putative overlaps between addiction and obesity in four domains: (1) personality research, (2) neurocognitive tasks, (3) brain imaging, and (4) clinical evidence. We suggest that three impulsivity-related domains are particularly relevant for our understanding of similarities between addiction and obesity: lower self-control (high Disinhibition/low Conscientiousness), reward sensitivity (high Extraversion/Positive Emotionality), and negative affect (high Neuroticism/Negative Emotionality). Neurocognitive studies have shown that obesity and addiction are both associated with increased impulsive decision-making and attention bias in response to drug or food cues, respectively. Mirroring this, obesity and different forms of addiction seem to exhibit similar alterations in functional MRI brain activity in response to reward processing and during self-control tasks. Overall, our review provides an integrative approach to understand those facets of obesity that present similarities to addictive behaviors. In addition, we suggest that therapeutic interventions targeting inhibitory control may represent a promising approach for the prevention and/or treatment of obesity.

Personality‐obesity associations are driven by narrow traits: A meta‐analysis

“…Obesity is a widespread and broadly consequential health condition, characterized by excess body fat. Studies using body mass index (BMI; kg/m 2 ) as a proxy for body fat percentage have associated BMI with several personality traits . As personality traits summarize stable patterns in how people typically think, act, feel, and behave, they may prove instrumental in delineating how people with obesity differ from people with normal weight status in their typical, weight‐relevant behaviour.…”

“…The domain‐level associations of BMI with higher Neuroticism and lower Conscientiousness may suggest a role of increased anxious behaviour and decreased self‐control capabilities . However, many details remain hidden in broad domain‐based findings.…”

“…The meta‐analysis by Emery and Levine similarly supported the link with Conscientiousness but additionally reported a positive association between BMI and the Neuroticism domain, a broad tendency to experience negative emotions. Reviews have further suggested that BMI may have a positive association with the Extraversion domain, capturing responsiveness to positive emotions, and negative associations with the Agreeableness domain, a trait reflecting altruism and being sympathetic with others. However, the same reviews and meta‐analyses have shown that these domain‐obesity associations vary substantially across studies and personality questionnaires …”

A neural signature of metabolic syndrome

“…Comorbidities of MetS, namely obesity, insulin resistance, and T2DM, have been studied extensively using functional imaging (Byrne & Wild, 2011). Task-activation fMRI studies (food picture, smell, and taste paradigms) have also shown that glucose infusion is associated with discrete brain activation patterns and prandial satiety, correlating with the brain's reward network (Huerta, Sarkar, Duong, Laird, & Fox, 2014;Michaud, Vainik, Garcia-Garcia, & Dagher, 2017). Task-activation fMRI studies (food picture, smell, and taste paradigms) have also shown that glucose infusion is associated with discrete brain activation patterns and prandial satiety, correlating with the brain's reward network (Huerta, Sarkar, Duong, Laird, & Fox, 2014;Michaud, Vainik, Garcia-Garcia, & Dagher, 2017).…”

Food addiction: A transdiagnostic construct of increasing interest

“…As reported in previous reviews (Steward et al, ; Treasure et al, ; Hebebrand et al, ; Volkow & Wise, ; Volkow et al, ; Gordon, Ariel‐Donges, Bauman, & Merlo, ), proponents of the FA model argue that there is sufficient scientific evidence to show that intake of certain high‐calorie/palatable foods and addictive drugs produce similar neural responses (linked to reward pathways modulated by dopamine) and therefore, to some extent, support the assumption that some types of overeating and obesity constitute a food addiction (Gearhardt, Davis, Kuschner, & Brownell, ; Schulte, Avena, & Gearhardt, ; Schulte, Yokum, Potenza, & Gearhardt, ; Smith & Robbins, ; Wiss, Criscitelli, Gold, & Avena, ; Michaud, Vainik, Garcia‐Garcia, & Dagher, ).…”