Bulimia Nervosa

Diagnostic Features and Prevalence

The DSM-IV (Diagnostic and Statistical Manual of Mental Disorders, 4th edition) defines several criteria for BN. Recurrent episodes of bingeing (and feeling a loss of control while bingeing) coupled with compensatory behaviors of purging must be present for a minimum of twice per week for 3 months. In addition, the individual's self-appraisal is influenced largely by perceptions of body weight and shape, and symptoms of BN must not occur during episodes of anorexia nervosa. There are two subtypes of BN: purging type, in which the individual regularly uses methods of self-induced vomiting or laxatives following binge episodes; and nonpurging type, in which individuals use other compensatory behaviors such as exercise or fasting, but do not engage in self-induced vomiting or laxatives.

The population prevalence of BN is approximately 1%, although estimates are as high as 10% in populations of females who are between 15 and 29 years of age. Research in college samples has documented as many as 19% of female students with symptoms of BN, but criteria differ across studies. More women may experience disordered eating at subclinical diagnostic criteria. While BN most often occurs in adolescent females and young adult women, approximately 5% to 15% of cases are males. BN can occur in older women and is increasingly documented in younger children. However, the typical age of onset is following puberty, when average levels of body fat in females increase from 8% to 22%, and when societal messages of thinness, dating relationships, and the need for peer acceptance become salient. Although there is insufficient data on prevalence, childhood-onset disordered eating typically occurs between ages 7 and 13, with boys representing 20% to 25% of cases. BN is believed to be more prominent among European American females who may face heightened pressures to be thin, but there is increasing evidence to suggest that African American women experience similar levels of body dissatisfaction and are also vulnerable to BN, perhaps because societal ideals of thinness are spreading across cultures (for more information on distribution and characteristics of BN, see Fairburn & Brownell, 2002).

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