Bulimia Nervosa: A Biobehavioral Study (The Eating Disorder Study)
Condition: Bulimia Nervosa
MeSH terms: Bulimia; Bulimia Nervosa
Study type: Observational

Summary: 
      The purpose of this study is to examine biological (e.g., energy expenditure, neuroendocrine
      and appetitive hormones)and behavioral (e.g., binge eating and purging) correlates of weight
      suppression and current dieting status in women with bulimia nervosa. The investigators have
      differentiated between a diet-induced long-term energy imbalance (weight suppression, or the
      difference between one's highest-ever body weight and current weight) and a short-term energy
      imbalance (current dieting to either lose weight or avoid weight gain). This study will
      elucidate how two common yet largely unexplored types of dieting influence biological and
      behavioral variables in patients with bulimia nervosa, which could lead to modifications of
      prevailing models of bulimia nervosa and new strategies for improving treatment outcome.
    

Detailed description: 
      Bulimia nervosa (BN) is a debilitating psychiatric disorder that primarily affects young
      women. Empirically supported treatments for BN have been identified but less than half of
      treated individuals achieve long-term remission from the disorder, possibly because current
      treatment approaches do not sufficiently account for variables that help maintain the
      disorder. Psychosocial models of BN emphasize the role of dieting as a proximal cause of
      binge eating and purging. Dieting has both psychological and biological facets but existing
      models of BN have overwhelmingly focused on its psychological impact. The investigators have
      differentiated between a diet-induced long-term energy imbalance (weight suppression (WS), or
      the difference between one's highest-ever body weight and current weight) and a short-term
      energy imbalance (current dieting to either lose weight or avoid weight gain). Recent
      research has shown that WS levels in BN are elevated and that degree of WS predicts the
      severity of various BN characteristics and its clinical course. Studies of current dieting
      (CD) to lose weight have found that it is associated with reduced binge eating in BN, a
      finding that conflicts with prevailing models of the disorder. The proposed research will
      examine biological (e.g., energy expenditure, neuroendocrine and appetitive hormones) and
      behavioral (e.g., binge eating and purging) correlates of WS and CD in those with BN.
      (Relatively few of those with BN report dieting to avoid weight gain but its biological and
      behavioral correlates will also be examined.) The project will recruit 132 women (66 at
      Drexel University and 66 at Columbia University) meeting provisional Diagnostic and
      Statistical Manual-V diagnostic criteria for BN. The investigators will test the hypotheses
      that 1) CD and elevated WS will be associated with alterations in biological indices of
      metabolism and appetite, 2) WS will predict greater binge eating and purging, and CD will
      predict less binge eating, measured using Ecological Momentary Assessment (EMA), and 3)
      higher real time ratings of daily food restriction intentions will predict a reduced
      probability of binge eating during the same day but an increased probability of binge eating
      in subsequent days. Assessments for all participants will include: weight and reported
      previous highest weight (to calculate WS), the Eating Disorders Examination, 14 days of EMA
      to assess food restriction intentions, binge eating and purging episodes, three 24-hr food
      recalls, and resting energy expenditure and metabolic and appetitive hormones (including
      complete thyroid panel, leptin, ghrelin, cortisol and estradiol). Participants will be asked
      to return 6 months later for follow-up assessments of weight. This study will elucidate how
      two common yet largely unexplored types of dieting influence biological and behavioral
      variables in patients with BN, which could lead to modifications of prevailing models of BN
      and new strategies for improving treatment outcome.
    

Observational model: Cohort
Time perspective: Other
Sampling method: Non-Probability Sample
Study population: 
        Participants will be recruited from local university counseling centers and eating disorder
        centers.
      
Keywords: Bulimia nervosa; Eating disorder; Weight suppression; Dieting