Virtual food for real thought: how to improve extinction learning in anorexia nervosa

患有神经性厌食症的人在吃饭时经历强烈的焦虑。这种焦虑通常与进食的前景和进食的后果有关，比如体重增加、难以控制的痛苦和对食物的失控。目前神经性厌食症的心理治疗鼓励患者与食物建立更积极的关系，但很少展示使用实用的策略来应对与食物有关的焦虑。该项目将使用虚拟食物的暴露来确定哪些机制强调成功减少神经性厌食症中与食物相关的焦虑。暴露疗法包括逐渐暴露于令人恐惧的刺激，是治疗焦虑症最有效的方法。在神经性厌食症中，食物暴露在改善饮食行为和促进体重增加方面取得了一定程度的成功。然而，食物暴露的机制在很大程度上仍然未经测试，结果是对能够最大化其功效的策略的理解有限。本研究将使用虚拟现实技术来测试食物暴露的机制。虚拟现实使研究人员能够创造类似于现实生活中所经历的环境，同时确保对测量变量的高水平控制。患有神经性厌食症的参与者将被暴露在一个虚拟厨房中，并被要求探索尽可能多的虚拟食物。他们对虚拟食物的焦虑和行为将被记录下来（例如，看、接近、抓、拿虚拟食物）。每个参与者将被随机分配到三种情况中的一种：接触虚拟食物(1)，接触虚拟食物同时与虚拟宠物互动(2)，接触虚拟食物同时与一个会说话的类人角色（AVATAR）互动，鼓励挑战饮食失调的声音(3)。在进入虚拟厨房后，参与者将被邀请参加一个味觉测试，在此期间，对一系列真实食物的焦虑和反应将被测量。假设是，与只接触虚拟食物的参与者相比，接触虚拟食物的参与者在接受积极情绪诱导或以康复为重点的社会支持的同时，在虚拟环境和味觉测试中，与食物相关的焦虑会减少得更多，并且会更接近食物。本研究旨在证明食物暴露、积极情绪诱导和康复导向的社会支持对神经性厌食症患者应对饮食相关焦虑的有效性。这个项目的临床潜力是开发一种新的干预方法，帮助人们与食物建立积极的关系。虚拟现实的使用确保了干预措施可以很容易地传播给患者，并在他们自己的环境中使用。

People with anorexia nervosa experience intense anxiety at mealtimes. The anxiety is often related to the prospect of eating and to the consequences of eating, such as weight gain, unmanageable distress, and loss of control over food. Current psychological treatments of anorexia nervosa encourage patients to develop a more positive relationship with food, but rarely demonstrate the use of practical strategies to cope with food-related anxiety. This project will use exposure to virtual foods to establish which mechanisms underline successful reduction of food-related anxiety in anorexia nervosa. Exposure therapy consists of gradual exposure to a feared stimulus and is the most effective treatment of anxiety disorders. In anorexia nervosa, food exposure has been used with some degree of success to improve eating behaviour and favour weight gain. However, the mechanisms of food exposure remain largely untested with the result that there is limited understanding of the strategies that can maximise its efficacy. This study will use the novel technology of virtual reality to test the mechanisms of food exposure. Virtual reality enables researchers to create environments that resemble those experienced in real life, while ensuring high levels of control over the variables which are measured. Participants with anorexia nervosa will be exposed to a virtual kitchen and asked to explore as many virtual food items as possible. Their anxiety and behaviours in response to the virtual foods will be recorded (e.g. looking at, approaching, grabbing, holding virtual foods). Each participant will be assigned by chance to one of three conditions: exposure to virtual foods (1), exposure to virtual foods while interacting with a virtual pet showing affection (2) and exposure to virtual foods while interacting with a talking human-like character (AVATAR) that encourages to challenge the eating disorder voice (3). Following exposure to the virtual kitchen, participants will be invited to take part in a taste-test, during which anxiety and behaviours in response to a range of real foods will be measured. The hypothesis is that participants exposed to the virtual foods while also receiving positive mood induction or recovery-focused social support will experience a greater reduction in food-related anxiety and will approach food more, both in the virtual environment and during the taste-test, compared to participants who only receive exposure to virtual foods. This study will prove the efficacy of food exposure, positive mood induction and recovery-oriented social support to help people with anorexia nervosa to cope with eating-related anxiety. The clinical potential of this project is to develop a novel intervention that helps people creating a positive relationship with food. The use of virtual reality ensures that the intervention can be easily disseminated to, and used by, patients over time and in their own environments.