L’obésité est une surcharge pondérale par excès de masse grasse qui a des conséquences néfastes pour la santé. Trouble chronique, d’origine multifactorielle, elle apparaît comme un facteur de risque sérieux qui compromet le fonctionnement psychosocial et la qualité de vie des patients. Cependant, elle ne fait pas partie du DSM-IV. L’obésité est une maladie invalidante, dont les particularités neurobiologiques, comportementales et émotionnelles restent à explorer. Néanmoins, un lien semble s’établir entre les troubles du comportement alimentaire, les perturbations de l’image du corps en lien avec l’estime de soi et la stigmatisation du sujet obèse, concepts fondamentaux semblant être partagés avec la maladie addictive.

Obesity is defined as being overweight from an excess of fat with harmful effects on health. It is a chronic disorder of complex etiology, a serious risk factor, which compromises psychosocial functioning and the patient’s quality of life. However, it is not a part of DSM-IV. Nevertheless, a link seems to be established between eating disorders, problems with one’s body image, self-esteem, stigmatisation and psychopathological disorders. Physical corporal satisfaction and dissatisfaction with regard to one’s body are two distinct aspects of the concept of bodily image. The major characteristic of dissatisfaction of social origin is the sensation of not being attractive; therefore, it is not an isolated cognition but truly one that reasons in reference to others, bringing avoidance behaviours as well as explaining a high probability of social phobia and agoraphobia in obese subjects. It would be tempting to think that social pressure could be a motivation to lose weight; however, this is not the case: dissatisfaction must be moderate in order to be stimulating. The dissatisfaction of an obese subject regarding his/her body seems to depend on several factors. Indeed, this disorder seems to be more frequent in female subjects suffering from bulimia and searching for help to lose weight, but the studies remain contradictory. However, differences according to sex seem well established and seem to have a neurobiological substratum. In effect, a recent study in functional RMI shows that when looking at their oversized deformed bodies, men and women do not activate the same networks. Women activate perception and emotional regulation circuits, men activate dorsal vision which analyses the body as an object in space. There are also ethnical differences, overweight black women seem less dissatisfied with their bodies than white women. The age at which obesity starts does not seem to influence the vision of one’s body, but the earlier obesity starts the longer dissatisfaction will continue after weight loss. Bodily image seems to improve with weight. Nevertheless, it seems to equally improve with cognitive and behavioural therapy such as low self-esteem and binge eating and this independently from weight loss. Negative images of one’s body could have major psychopathological and psychosocial consequences. They can start or aggravate eating problems, social anxiety, depressions, sexual problems and low self-esteem. Women maintain some dissatisfaction and anxious concerns with their bodies. The severity of a negative bodily image seems to be linked to the amount of stigmatisation suffered. Discrimination starts at a very young age, six-year-old children described obese subjects as stupid, lazy, dirty, liars and cheaters and adults as incompetent and emotionally unstable. Negative attitudes towards obese subjects are widespread throughout the medical profession. Obesity is also the subject of professional discrimination. Massive obesity also seems to be an obstacle to marriage and a source of conjugal and sexual dysfunction, especially if it started recently. However the quality of life, social and professional activities, relations with others, body image and sexuality seem to improve with weight loss. Subjects who adopt positive strategies for coping with stigmatisation show more self-esteem and a lesser degree of dissatisfaction towards their bodies. Stigmatising experiences in female subjects seems to start or reinforce low self-esteem, dissatisfaction with their life style, social anxiety, depressions and eating disorders. Indeed, three population groups seem particularly at risk of psychiatric problems: female obese subjects. They are more at risk from changes to bodily perception, discrimination and negative psychosocial consequences. They suffer 10 times more than men from eating disorders. They are at risk from social behaviour problems and even personality problems; the obese suffering from a binge eating disorder represents about 5% of the obese population. They incur the largest risk of a psychopathology of axe 1 (including substance abuse and dependency) with more serious depressions. They are also at risk from bodily image disorders with low self-esteem and more important psychopathological consequences; the morbidly obese cover about 5% of obese subjects. They also are at great risk from psychopathological disorders. A larger prevalence of subjects suffering from binge eating disorders, behavioural problems, anxiety problems, bulimia, addiction to tobacco and personality problems are found here. Obesity and depression share many common points, from a clinical behavioural and emotional point of view but also from a neurobiological one. In women obesity and major depressive syndromes, atypical depressive syndromes, suicidal thoughts and attempted suicides are positively correlated. A young obese woman with a bad bodily image is at a high risk from depression. Males incur a high risk of depression, suicidal thoughts and suicide attempts for a BMI less than 20.8. One of the key symptoms of depression is anhedonia. The link between obesity and anhedonia has been studied in reports through behavioural studies on sensibility to rewards of which the neurobiological bases rest on the dopaminergic mesolimbic transmission. A significant decrease in the number of dopamenergic D₂ receivers was observed in obese subjects in line with the decrease in sensitivity towards reward. The neurobiological profile of obesity in men decreases, it is inversely proportional to the BMI and associated with prefrontal cortex anomalies. This invalidating disease shows neurobiological, behavioural and emotional peculiarities, which remain to be investigated.