Bulimia Nervosa Notes

Bulimia Nervosa

Overview

This mini-lecture covers:

  • Diagnostic Criteria for Bulimia Nervosa (BN)

  • Cognitive-Behavioral Models of Bulimia Nervosa

  • Treatment Outcome for Bulimia Nervosa

Required Prior Readings

  • Rieger (2017) Chapter 9. Eating Disorders.

Diagnostic Criteria

Bulimia Nervosa involves:

  • Recurrent episodes of binge eating.

  • Eating an abnormally large amount of food in one sitting.

  • A sense of a lack of control over eating during the episode.

  • Recurrent inappropriate compensatory behavior to prevent weight gain.

  • These behaviors occur at least twice per week over a three-month period.

  • Self-evaluation is unduly influenced by body shape and weight.

  • The disturbance does not occur exclusively during episodes 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: Chronic and intermittent courses are observed.

Severity Spectrum

The severity of bulimia can be viewed along a spectrum:

  • Less Severe: Binge Eating Disorder

  • Intermediate: Bulimia Nervosa without Purging Behavior

  • More Severe: Bulimia Nervosa with Purging Behavior

CBT Conceptualization

  • Psychosocial influences play a significant role.

  • Current cultural milieu emphasizes thinness.

  • Correlation exists between cultural pressure to be thin and eating disorder prevalence across and within cultural groups (Hsu, 1990).

  • Family factors contribute to vulnerability.

  • Some argue for similarities between BN and OCD (Rubenstein, 1995).

  • BN patients exhibit higher levels of obsessional traits compared to normal controls.

CBT Model of BN

The CBT Model of BN includes:

  • Societal Milieu (Streigel-Moore et al., 1986; Hsu, 1990)

  • Family Comments regarding Eating/Weight (Fairburn et al., 1997)

  • Vulnerability Factors (Fairburn et al., 1997):

    • Obesity / Psychological Factors

  • Overvalued Importance of Shape/Weight (Fairburn, 1997)

  • Vulnerability to Eating Disorders (Strober et al., 2000)

  • Rigid Standards for Control of Eating (Fairburn, 1997)

  • Disordered Chaotic Eating

  • Attempts to Diet (Patton et al., 1990)

  • Hunger

  • Lapse

  • Binge

  • Purge

  • Negative Reinforcement: Reduced Distress

  • Increase in Distress

  • Breakdown in normal conditioning processes that regulate eating (Wilson & Pike, 2001)

The Role of Dieting

  • Dieting behavior is a risk factor for BN.

  • In a study of 15-year-old schoolgirls, those who dieted were 8 times more likely to develop an eating disorder within a one-year period compared to those who did not restrict food intake.

  • However, dieting alone is not a sufficient factor; only 20% of those dieting developed an eating disorder (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

The cognitive model incorporates:

  • Extreme Concerns About Shape and Weight

  • Intense and Rigid Dieting

  • Binge Eating

  • Self-Induced Vomiting or Laxative Misuse

  • Perfectionism & Dichotomous Thinking

  • Negative Affect

  • Negative Self-Evaluation

Treatment Outcome for BN

  • Whittal, Agras, & Gould (1999) conducted a meta-analysis:

    • Evaluated 26 studies of CBT with BN (N=460).

    • Found effect sizes of 1.221.22 to 1.351.35 of CBT on Binge eating, Purging, Depression symptoms, Eating attitudes

  • Hay & Bacaltchuk (2000) performed a Cochrane Review:

    • Identified 21 controlled studies of BN.

    • Compared CBT vs. no treatment, delayed treatment, alternative psychotherapy, self-help CBT.

    • CBT was superior to no treatment or delayed treatment.

    • CBT approached significance compared to other psychotherapies (Wilson & Fairburn, 2002).

  • BN has the most research and highest quality treatment outcome studies among eating disorders.

  • Response rates are generally reported 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 using bingeing and purging behavior as the only outcome measure and reported variable findings of CBT's impact on core cognitive symptoms (Wilson & Fairburn, 2002).

Summary

This mini-lecture covered the diagnostic criteria, cognitive-behavioral models, and treatment outcomes for Bulimia Nervosa.