Affect, cognition, awareness and behavior in eating disorders : comparison between obesity and anorexia nervosa

(eng) Eating is a highly motivated and reinforced behaviour, therefore human eating behaviour is not a passive response or merely physiological drives providing nutrients for survival; it is about cognitive and emotional processes based choice. Obesity is a condition in which the natural energy reserve, stored in the fatty tissue of humans is increased to a point where it is associated with certain health conditions or increased mortality. Anorexia nervosa is a condition of self initiated weight loss characterised by a profound disturbance of the body image, distorted self-perception, and obsessive fear of gaining weight and problem in the cognitive and the emotional functioning. Continuum model proposed that eating disorders from restriction to overeating can be placed on a linear dimension. Aim: The main goal of the doctorate thesis is to examine the existence of certain common dysfunction related to the two extreme sides of the dimension of the eating disorders (restrictive anorexia and stable obesity). Therefore we compared cognitive profile, emotion functioning (explicit and early categorization of facial emotions) and attitudes (explicit and implicit) towards body image both in obesity and anorexia. Results: The neuropsychological tasks show attentional deficit and distractibility in obesity and anorexia nervosa. In obesity we have found perseveration, deficit on the shifting and inhibition capacity, while in anorexia nervosa perseveration was linked to anxiety. These findings suggest that the PFC based executive function can be associated with modified brain dopamine turnover in the PFC area in obesity. Beside, the higher level of depression in both patient groups; our findings proved that obese patients were more sensitive to the positive emotions and the same time they ignored the negative emotions. In contrary to obesity, anorexic patients were more sensitive to negative emotions specifically those one which represent possible threats such as anger. Obese patients evaluated implicitly more positive the overweight body figures than controls. There was an attitudinal discrepancy between the explicit, socially exposed “ideal body” and the internal (implicit) body shape preference. The anorexic group did not evaluate positively the underweight body shape as we expected either implicitly or explicitly. Based on these findings we suggest that not the underweight body preference is a key issue in anorexia, but the obsessive fear for the obesity. Conclusion: We have found different psychological mechanisms in the pathology of restrictive anorexia nervosa and stable obesity. Our results did not confirm the idea of the continuum model about the linear spectrum based on eating behaviour (from the restriction to overeating), and from body weight (from underweight to obese). Our results suggest that restrictive anorexia nervosa has several common features with anxiety disorder or affective disorders, while obesity most probably can be associated with addictive pathologies.