Neuroanatomical correlates of food addiction symptoms and body mass index in the general population.

The food addiction model suggests neurobiological similarities between substance-related and addictive disorders and obesity. While structural brain differences have been consistently reported in these conditions, little is known about the neuroanatomical correlates of food addiction. We therefore aimed to determine whether symptoms of food addiction related to body mass index (BMI), personality, and brain structure in a large population-based sample. Participants of the LIFE-Adult study (n = 625; 20-59 years old, 45% women) answered the Yale Food Addiction Scale (YFAS) and further personality measures, underwent anthropometric assessments and high-resolution 3T-neuroimaging. A higher YFAS symptom score correlated with higher BMI, eating behavior traits, neuroticism, and stress. Higher BMI predicted significantly lower thickness of (pre)frontal, temporal and occipital cortex and increased volume of left nucleus accumbens. In a whole-brain analysis, YFAS symptom score was not associated with significant differences in cortical thickness or subcortical gray matter volumes. A hypothesis-driven Bayes factor analysis suggested a small, additional contribution of YFAS symptom score to lower right lateral orbitofrontal cortex thickness over the effect of BMI. Our study indicates that symptoms of food addiction do not account for the major part of the structural brain differences associated with BMI in the general population. Yet, symptoms of food addiction might explain additional variance in orbitofrontal cortex, a hub area of the reward network. Longitudinal studies implementing both anatomical and functional MRI could further disentangle the neural mechanisms of addictive eating behaviors.

Similarities and Differences in Neuroimaging.

Addiction is a chronically relapsing disease characterized by drug intoxication, craving, bingeing, and withdrawal with loss of control. An increasing number of studies have indicated that non-substance addiction, like internet addiction and pathological gambling, share clinical, phenomenological, and biological features with substance addiction. With the development of imaging technology in the past three decades, neuroimaging studies have provided information on the neurobiological effects, and revealed neurochemical and functional changes in the brains of both drug-addicted and non-substance addicted subjects. Imaging techniques play a more critical role in understanding the neuronal processes of addiction and will lead the direction in future research for medication development of addiction treatment, especially for non-substance addiction, which shares an increasing percentage of addiction disorder. This article will review the similarities and differences between substance and non-substance addiction based on neuroimaging studies that may provide clues for future study on these two main kinds of addiction, especially the growing non-substance addiction.

Alterations in reward network functional connectivity are associated with increased food addiction in obese individuals.

Functional neuroimaging studies in obesity have identified alterations in the connectivity within the reward network leading to decreased homeostatic control of ingestive behavior. However, the neural mechanisms underlying sex differences in the prevalence of food addiction in obesity is unknown. The aim of the study was to identify functional connectivity alterations associated with: (1) Food addiction, (2) Sex- differences in food addiction, (3) Ingestive behaviors. 150 participants (females: N = 103, males: N = 47; food addiction: N = 40, no food addiction: N = 110) with high BMI ≥ 25 kg/m2 underwent functional resting state MRIs. Participants were administered the Yale Food Addiction Scale (YFAS), to determine diagnostic criteria for food addiction (YFAS Symptom Count ≥ 3 with clinically significant impairment or distress), and completed ingestive behavior questionnaires. Connectivity differences were analyzed using a general linear model in the CONN Toolbox and images were segmented using the Schaefer 400, Harvard-Oxford Subcortical, and Ascending Arousal Network atlases. Significant connectivities and clinical variables were correlated. Statistical significance was corrected for multiple comparisons at q < .05. (1) Individuals with food addiction had greater connectivity between brainstem regions and the orbital frontal gyrus compared to individuals with no food addiction. (2) Females with food addiction had greater connectivity in the salience and emotional regulation networks and lowered connectivity between the default mode network and central executive network compared to males with food addiction. (3) Increased connectivity between regions of the reward network was positively associated with scores on the General Food Cravings Questionnaire-Trait, indicative of greater food cravings in individuals with food addiction. Individuals with food addiction showed greater connectivity between regions of the reward network suggesting dysregulation of the dopaminergic pathway. Additionally, greater connectivity in the locus coeruleus could indicate that the maladaptive food behaviors displayed by individuals with food addiction serve as a coping mechanism in response to pathological anxiety and stress. Sex differences in functional connectivity suggest that females with food addiction engage more in emotional overeating and less cognitive control and homeostatic processing compared to males. These mechanistic pathways may have clinical implications for understanding the sex-dependent variability in response to diet interventions.

Food addiction: A common neurobiological mechanism with drug abuse.

Drugs and food both exert a rewarding effect through the firing of dopamine neurons in the ventral tegmental area, resulting in the release of dopamine into the nucleus accumbens and effects on the mesolimbic pathway. Here, we review the neuroimaging literature to consider the validity of food addiction and the common neurobiological mechanisms that overlap in food and drug addiction. This review paper focuses on findings from Positron Emission Tomography (PET), functional Magnetic Resonance Imaging (fMRI) and structural imaging studies, as well as evidence from neuroimaging studies of bariatric surgery and pharmacological interventions on obese individuals. We examine not only functional and structural changes in the mesolimbic pathways, but also in other frontal areas shown to be involved in drug addiction, including the prefrontal cortex, orbitofrontal cortex and anterior cingulate cortex, as well as changes in neurotransmitter systems beyond dopaminergic systems.

Altered brain correlates of response inhibition and error processing in females with obesity and sweet food addiction: A functional magnetic imaging study.

BACKGROUND: The aim of the present study was to evaluate the impulsivity and brain correlates of response inhibition and error processing among females with obesity and sweet food addiction (O & SFA). METHODS: We evaluated the response inhibition and error processing by functional magnetic resonance imaging (fMRI) in subjects with O & SFA and controls. Twenty females with O & SFA and 20 controls were recruited. All subjects performed the event-related designed Go/No-go task under fMRI and completed questionnaires related to food craving and impulsivity. RESULTS: The O & SFA group exhibited a higher score for impulsivity than did the control group. The O & SFA also exhibited lower brain activation when processing response inhibition over the right rolandic operculum and thalamus than controls. Both O & SFA and control groups exhibited activation of the insula and caudate during error processing. The activation over the left insula, precuneus, and bilateral putamen were higher in the subjects with O & SFA than for those in the control group. CONCLUSION: Our results support the fact that the fronto-striatal network is involved in response inhibition, and the caudate and insula contributes to error processing. Furthermore, women with O & SFA have impaired rolandic operculum when processing response inhibition and have greater insular and putamen activation in maintain their error processing function.