La mesure des émotions suscitées par des images de nourriture chez des femmes présentant un trouble des conduites alimentaires

Authors: Gagnon, Caroline
Advisor: Grondin, SimonBégin, Catherine
Abstract: Eating disorders (ED), more specifically anorexia nervosa (AN) and bulimia nervosa (BN), are serious mental illnesses. In that sense, their etiology is multi-determined, their comorbidity is high, their consequences are severe and multiple, and the road to their recovery is a sinuous path. In addition, for a number of patients, ED are long-lasting diseases due to the mixed results of their treatment or, in other words, to the continuity of their symptoms after being discharged from a specialized care program. Since a few years, unconscious, automatic and intuitive processes, like emotions, are recognized for their important influence on food intake. Notably, Macht’s Five-way Model (2008) postulates that food-evoked emotions are powerful determinants of food choice because, in a hierarchical perspective, they represent the first way by which emotions can control individuals’ food intake. In fact, the hedonic value of food has been demonstrated to be predictive of energy consumption and/or the amount of food consumed at a meal. Instead of investigating emotions experienced by ED women in their general life, the present thesis is interested in food-induced emotions as potential explanatory factors of inadequate patients’ food intake. To that end, emotional responses of participants suffering from AN and BN are compared to those of healthy controls (HC) and to those aroused by object images. The first objective of the thesis is to identify food-induced emotions that are distinctive in ED, by using explicit/direct measures of emotions and controlling for previous studies’ limitations. The results show that ED patients experience a higher level of fear towards food pictures than HC, which is specific to their pathology. Differently said, that food-evoked reaction is neither due to the use of heterogenous stimuli, nor to patients’ internal state (hunger, pre-experimental emotional symptoms), nutritional knowledge and potential higher disgust sensitivity or general anhedonia. In more details, in AN women, the fear response occurs towards all food, whereas in BN women, that is observed for high-caloric products only. The second objective of the thesis is to validate the food-induced emotions obtained by explicit tasks with implicit/indirect measures, in order to avoid biases associated to the latter and to help alleviating ambiguity in the literature about BN women’s indirect and direct reactions towards food. Because psychophysiological recordings, as traditional implicit techniques, are somewhat invasive and unpleasant – particularly for ED women who are biologically monitored on a recurring basis – a different method is used, namely the presentation of food pictures and judgements about the duration of these presentations. The time perception perspective adopted is based on the fact that timing is sensitive to emotions and that temporal distortions give insights about how the environment is processed. The results revealed that AN women overestimate the duration of food pictures in comparison to pictures of objects. Also, compared to participants with BN, they perceive the duration of food pictures as longer. However, BN patients do not show any time distortion for food pictures. The overestimation effect observed in AN women for food pictures is understood as the effect of a fear reaction, which is shown, once more, to be ED-specific. Considered all together, the findings of the present thesis demonstrate that emotions provoked by food, as stimuli per se, generate an intense reaction of fear in women suffering from an ED. Since fear induced by a food product leads to its rejection – and considering that the more an item is avoided, the more the fear associated with it increases – the thesis highlights the need to address distinctly and exhaustively patients’ fear toward food as soon as they begin treatment. For this purpose, as a complement to AN and BN validated therapies, the use of clinical strategies applied for the management of anxious disorders appears to be a promising avenue (e.g., exposure and response prevention).
Document Type: Thèse de doctorat
Issue Date: 2019
Open Access Date: 9 January 2020
Grantor: Université Laval
Collection:Thèses et mémoires

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