Decision making in obesity: BY-self and in the group. A functional magnetic resonance imaging study

INTRODUCTION: Obesity is an important and widespread public health problem that can cause number of morbitities and mortility. Etiology can be listed such as medical or metabolic disorders, side effects of various medications, mental disorders or abnormal eating attitudes. Recently, group treatments are becoming more highlighted in obesity treatment. The better outcomes of group treatments than individual treatments such as more decrease in body weight and drop-out rates are promising. AIM: The aim of this study is to investigate the decision-making process and predisposition to social interaction of obese people and obtain data about the neural correlates of these processes. HYPOTHESIS: Obese people would make more disadvantageous decisions compared to normal-weighted ones when they act individually. However, obese would establish advantageous decision-making strategies when they are a part of a group, via social interactions and conformity. Activation changes in different regions of the brain is also expected. METHOD: 22 obese and 22 normal- weighted subjects were included. Eating attitudes, emotion regulation strategies and psychological features were assessed by self-report questionnaires. Iowa Gambling Task (IGT) was performed for the evaluation of decision- making strategies. At the same time, functional magnetic resonance imaging was performed for the investigation of brain activity changes. Statistical analyses were done by chi- square, Mann Whitney U, Two-way ANOVA for mixed samples and Spearman correlation tests. RESULTS: Emotional eating was prominent in the obese group. IGT net scores were not statistically different among the groups. Obese subjects showed hypoactivation in insula, cingulate cortex, caudate, parahippocampal gyrus, amygdala, interior parietal lobule, temporapolar region and frontal cortex; while decision-making. CONCLUSION: Hypoactivation in the brain regions associated with emotion processing, memory, theory of mind and reward valuation in obese subjects the reveal difference in decision-making strategies; compared to normal-weighted subjects. The differences found while group performance would be helpful in order to modify individual and group treatment approaches for against obesity.