Reward Systems and Food Avoidance in Eating Disorders
Condition: Low Weight Eating Disorders; Anorexia Nervosa
MeSH terms: Anorexia; Feeding and Eating Disorders; Anorexia Nervosa
Study type: Interventional

Summary: 
      The researchers plan to explore brain networks involved in emotion processing and learning
      using a brain scan and test meals. One core feature of Anorexia Nervosa (AN) is eating a
      small number of high-calorie or high-fat foods. By studying why individuals with AN are
      disgusted by food or other eating situations, the researchers will be able to understand more
      about the neurobiological pathways that lead to restricting food intake and food avoidance.
      This study also aims to find whether one of two short-term interventions (Interoceptive
      Exposure (IE); Family-Based Therapy (FBT)) affects connections in the brain and if the
      treatments affect food avoidance. IE is an intervention that helps reduce anxiety about
      eating. FBT is an intervention that motivates patients to eat through working with family to
      increase the value of eating and decrease the value of avoiding foods.
    

Detailed description: 
      Anorexia nervosa (AN), a characteristically relentless pursuit of thinness with an intense
      fear of weight gain despite significantly low body weight, is a serious psychiatric disorder
      with high rates of morbidity and mortality. Low weight eating disorders (LW-ED), the broader
      category of eating pathology that includes AN and similar variants, are characterized by a
      chronic course, poor response to treatment, and food avoidance. Emerging neuroimaging
      evidence suggests that deficits in insula-amygdala-ventral striatum (IAVS) neurocircuitry
      contribute to individual variability in aversive and reward learning, and that these brain
      regions demonstrate abnormal responses to food/eating stimuli. The researchers' pilot data
      suggest that patients with LW-ED experience difficulty extinguishing food-cue associations in
      a reversal learning paradigm compared to healthy controls, a difficulty that is related to
      psychophysiological measures of aversive disgust (not fear). The researchers have also
      successfully piloted an interoceptive exposure intervention for this population that targets
      visceral sensitivity and seeks to increase 'top-down' regulation of the IAVS neurocircuit.
      The proposed project will (a) use novel fMRI-EMG to test the relationship between effective
      connectivity within amygdala-insula-ventral striatum network and its relationship to
      psychophysiological and behavioral measures of acute threat and reward learning in 60
      adolescents with LWEDs and 30 healthy controls, (b) test the sensitivity of this network to
      an experimental interoceptive exposure paradigm relative to patients receiving family based
      therapy for weight restoration using dynamic causal modeling of fMRI-EMG data pre-post
      experimental conditions, (c) validate this model against objective measures of laboratory and
      real world eating behavior. The results of this study will help better understand the core
      neurocircuitry that underlies both threat processing and reward/aversive learning and how
      this circuit relates to objective behavior. Further, the researchers will determine the
      modifiability of this neurocircuitry via two distinct behavioral interventions chosen to
      target different aspects of affective processing and reward learning. These data will be used
      to inform future clinical interventions targeting aversive/reward learning within this
      population and dysregulation in insula-amygdala-ventral striatum subcircuits.
    

Intervention name(s): Interoceptive Exposure (IE); Family Based Therapy-Weight Gain Control (FBT-WG); meal replacement shake
Intervention type(s): Behavioral; Behavioral; Dietary Supplement
Intervention description(s): Participants are provided with a meal replacement shake of 'unknown' Kcal or macronutrient content and are asked to mindfully observe the sensations (aversive taste, texture, bloating, icky feeling, etc.) and associated emotional states (i.e., disgust) with the empathetic support of parents/therapist in session, without expectation of habituation. Sessions occur on a weekly basis with session one lasting 2 hrs. The remaining 5 sessions last one hour, and participants eat a meal replacement shake over 30-minutes, identical to the first session. All sessions include debriefing and development of IE homework that includes daily practice of IE.; Participants and families randomized to FBT-WG will receive 6-weeks of FBT treatment for AN. Sessions occur weekly, with the first session lasting two hours and the remaining 5 sessions one hour. FBT is atheoretical in terms of the etiology, but uses parent-enforced contingencies to increase value of eating and decrease the value of food avoidance.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: Eating Disorders; Food Avoidance; Reward Learning; Reward System; Family-based treatment; interoceptive exposure; insula-amygdala-ventral striatum subcircuits