Addressing the fear of fat: extending imaginal exposure therapy for anxiety disorders to anorexia nervosa

Abstract

Exposure therapy is fundamental for the treatment of core fears in anxiety disorders and it has been proposed that exposure therapy should be extended to Anorexia Nervosa (AN)[1]. Exposure therapy for AN has primarily focused on exercises such as mirror exposure to address body image anxiety and food exposure to address avoidant eating behavior[1]. Recently, exposure for mealtime anxiety was shown to be more efficacious than cognitive remediation therapy[1]. These types of exposure therapy show promise for the treatment of AN. However, they are limited because they only address stimuli that are accessible invivo (food, bodies). Therefore, they may not expose the patient to all of their fears, including the core fear of fatness, which can be conceptualized as an irrational belief driving avoidance behavior[1]. In imaginal exposure, patients are able to address hypothetical fears that cannot be replicated in everyday life (e.g., immediate fatness or abandonment). Imaginal exposure is highly effective for anxiety disorders and is the core feature of Prolonged Exposure Therapy for PTSD[PET;2]. In PET, patients create a script recounting their traumatic experience with the help of their therapist. The script is edited throughout treatment to focus on the most feared aspects of the trauma, which often elicits previously unidentified fears. Imaginal exposure is audio-recorded, and the patient listens to the recording as daily homework. Through this type of exposure therapy, patients learn to face their fears and learn that they can tolerate the anxiety elicited by discussing those fears. Imaginal exposure therapy draws on the avoidance-anxiety model[3]. In this model, avoidance is the chief maintaining factor of anxiety. For example, a patient with PTSD fears that she will re-experience her trauma. Motivated by the anxiety produced by this fear, she avoids leaving her house after dark because nighttime is associated with trauma. Therefore, she never learns that she can leave the house after dark and not re-experience trauma. Alleviation of anxiety becomes increasing paired with avoidance behavior via a process of negative reinforcement, promoting the maintenance of the disorder. Imaginal exposure is used in anxiety disorders to face fears that are not accessible or practical to address via in-vivo exposures. For example, a patient with PTSD cannot re-experience her trauma in real life, but she can imagine the past trauma and experience the subsequent anxiety. In AN, fear of fat is the central fear driving avoidance of eating[1]. Patients associate becoming fat with negative consequences, such as abandonment. Avoidance of eating prohibits learning that maintaining an optimal weight is not a predictor of such catastrophic outcomes. For patients with AN, catastrophic outcomes such as abandonment or immediate fatness are similarly impossible to recreate as in-vivo exposures. Patients cannot become fat solely for the purpose of the exposure, but they can imagine what it would be like to become fat. We theorize that using imaginal exposure to face the fear of hypothetical fatness can break the avoidance-anxiety cycle. We are unaware of any literature using imaginal exposure therapy to induce fears of fatness and conducted a case study to test whether imaginal exposure was feasible to (a)induce fears of fatness and (b)promote reduction in anxiety and eating disorder symptoms.