Bulimia Nervosa Notes

Bulimia Nervosa

Diagnostic Criteria

  • Recurrent episodes of binge eating: Eating an abnormally large amount of food in one sitting.
  • Perception of lack of control over eating: Feeling unable to stop eating.
  • Recurrent inappropriate compensatory behavior: Actions taken to prevent weight gain (e.g., vomiting, laxatives).
  • Frequency: Occurring at least twice per week over a three-month period.
  • Self-evaluation: Unduly influenced by body shape and weight.
  • Exclusion: Not occurring exclusively in the context of Anorexia Nervosa. (APA, 2013)

Prevalence and Course

  • Prevalence: 1-3% lifetime prevalence.
  • Gender: 10 times more common in females than males.
  • Onset: Typically in late adolescence or early adulthood.
  • Course: Can be chronic and intermittent.

Severity Spectrum

  • The spectrum ranges from less severe to more severe, including:
    • Binge Eating Disorder
    • Bulimia Nervosa without Purging Behavior
    • Bulimia Nervosa with Purging Behavior

CBT Conceptualization

  • Psychosocial influences: Current cultural milieu. Correlation between cultural pressure to be thin and eating disorder prevalence, across and within cultural groups (Hsu, 1990).
  • Family factors
  • Vulnerability factors (Fairburn et al., 1997)
  • Similarity between BN and OCD (see Rubenstein, 1995). BN patients show higher levels of obsessional traits than normal controls.

CBT Model of BN

  • Societal Milieu
    • Streigel-Moore et al. (1986)
    • Hsu (1990)
  • Family Comments Regarding Eating / Weight
    • Fairburn et al. (1997)
  • Rigid Standards for Control of Eating
    • Fairburn (1997)
  • Vulnerability Factors
    • Obesity / Psychological Factors
    • Fairburn et al. (1997)
  • Overvalued Importance of Shape / Weight
    • Fairburn (1997)
  • Vulnerability to Eating Disorders
    • Strober et al. (2000)
  • Disordered Chaotic Eating
  • Attempts to Diet
    • Patton et al. (1990)
  • Hunger
  • Lapse
    • Negative Reinforcement
    • Reduced Distress
  • Loss of Control
  • Binge
  • Purge
    • Increase in Distress
  • Breakdown in normal conditioning processes that regulate eating. (Wilson & Pike, 2001)

The Role of Dieting in BN

  • Dieting behavior is a risk factor for BN.
  • In 15-year-old schoolgirls, those who diet were 8 times more likely to develop an eating disorder within a one-year period than those who did not restrict food intake.
  • But dieting was not a sufficient factor alone in BN. Only 20% of those dieting went on to develop an ED. (Patton et al., 1990)
  • Patients consistently report the onset of binge eating behavior following a period of dieting. (Wilson & Pike, 2001)

Cognitive Model of Bulimia Nervosa

  • Cognitive: Extreme Concerns About Shape and Weight
  • Perfectionism & Dichotomous Thinking
  • Negative Self-Evaluation
  • Intense and Rigid Dieting
  • Binge Eating
  • Self-Induced Vomiting or Laxative Misuse
  • Negative Affect

Treatment Outcome for BN

  • Whittal, Agras, & Gould (1999) Meta analysis of 26 studies evaluating CBT with BN. (N=460) Found effect sizes of 1.22 to 1.35 of CBT on Binge eating, Purging, Depression symptoms, Eating attitudes
  • Hay & Bacaltchuk (2000) Cochrane Review Identified 21 controlled studies of BN Compared CBT vs no treatment, delayed treatment, alternative psychotherapy, self-help CBT.
  • CBT found to be superior to no treatment or delayed treatment
  • CBT approached significance in comparison to other psychotherapies (Wilson & Fairburn, 2002)
  • BN is the eating disorder with the most research into treatment outcome, and treatment outcome studies of the highest quality. Response rates are generally reported at around 50% (Wilson, Fairburn & Agras, 1997)
  • Cognitions must be addressed in addition to behavioral techniques to prevent relapse (Cooper & Steere, 1995)
  • Anderson & Maloney (2001) were critical of the use of bingeing and purging behavior as the only outcome measure and reported variable findings of the impact of CBT on core cognitive symptoms. (Wilson & Fairburn, 2002)