Abstract
The objective of this thesis is articulated around two axes: on the one hand the validation and the adaptation of a multidimensional assessment disgust tool in French and on the other hand the evaluation of the effectiveness of an extinction strategy of a disgust reaction by a counter conditioning procedure in nonclinical and analogue populations suffering from obsessive compulsive disorder.A first psychometric study was conducted with a sample of 282 participants to validate in French the disgust propensity and sensibility scale, a factorial scale for assessing disgust outside of specific contextual triggers. This scale measures individual responses to concerns about the autonomic reactions typically associated with disgust (eg nausea): disgust sensitivity and the frequency and intensity with which an individual can be disgusted: disgust propensity. Two central dimensions in understanding the emotion of disgust. Our analyzes validate the original factorial structure with two factors after removing two items of the sensitivity factor more oriented toward a self-directed disgust sensitivity. Correlation analyzes showed distinct associations of the two constructs, propensity was more related to the behavioral dimensions of obsessive-compulsive disorder while the sensitivity was more related to cognitive dimensions and concerns about the cognitive, social and physiological consequences of anxiety. The regression analyzes have above all shown that, controlling the different dimensions of anxiety and negative affects, washing behavior was exclusively explained by disgust propensity. Our data confirm the two-dimensional factor structure of the emotion of disgust and the specific link that each of them has with different manifestations of obsessive-compulsive disorder. They also emphasize the unique role of disgust in fear of contamination beyond different constructs of anxiety. The validation of this scale allowed us to explore these dimensions of disgust in an experimental study, differentiating predictive learning (the anticipation of an unconditional stimulus after a neutral stimulus) and evaluative learning (valence transfer from an unconditional stimulus towards a neutral stimulus). This experiment was designed to test the effectiveness of a counter-conditioning procedure on the extinction of a disgust reaction acquired in two groups of participants with high or low concerns about dirt and contamination. Analysis of variance shows that the counter-conditioning procedure succeeds in significantly reducing the anticipation of the disgusting unconditioned stimulus and the valence transferred to the neutral conditioned stimulus. The reduction in anticipation and valence was more moderate in the group with high concerns about dirt and contamination than in the group with low concerns. Correlation analyzes show that the dimension of disgust sensitivity self-reported is strongly correlated with the acquisition and maintenance of a conditioned disgust response, while the anticipation of the unconditional stimulus is predicted by the intensity of the self-reported anxiety. The observed data confirm the differential nature of predictive and evaluative learning. Preliminary results show that counter conditioning is a strategy that reduces the associations of occurrence and valence transfer from disgusting unconditional stimuli to initially neutral stimuli.In the light of its results, we can consider that disgust is a multidimensional construct, whose factors have a unique and specific impact in contamination obsessions, dissociable from that of anxiety. Disgust represents a therapeutic target to be privileged, the dimensional aspect is to be taken into account in order to propose adapted management strategies. Its means of desensitization are specific and must favor strategies that take into account the mechanisms of evaluative learning.