Prevalence and Long-Term Course of Lifetime Eating Disorders in an Adult Australian Twin Cohort

Abstract

Objective: Few studies exist that have examined the spectrum and natural long-term course of eating disturbance in the community. We examine the lifetime prevalence and long-term course of anorexia nervosa (AN), bulimia nervosa (BN) and eating disorder not otherwise specified (EDNOS) in an adult female twin population. Method: Female twins (n = 1002) from the Australian Twin Registry, aged 28–39 years, were assessed using the Eating Disorder Examination, revised to yield lifetime diagnostic information. For women with lifetime eating disorders, the assessment occurred, on average, 14.52 years (SD = 5.65) after onset of their disorder. Results: In accordance with other community studies, we found a 1.9% lifetime prevalence of AN, with an additional 2.4% who met the criteria for ‘partial AN’ (absence of amenorrhea). Criteria for BN were met by 2.9% of the women, an additional 2.9% of women met criteria for binge eating disorder, while 5.3% met criteria for purging disorder unaccompanied by binge eating (EDNOS-p). Eleven (7%) of the women with lifetime eating disorders had a current eating disorder. Each diagnostic group continued to be differentiated by current eating pathology from women without lifetime eating disorders. Although approximately 75% of the women had a good outcome, less than 50% of each diagnostic group was asymptomatic. Conclusions: Eating disorders tend to improve over time often reaching subdiagnostic levels of severity, but only a minority of sufferers becomes asymptomatic. The DSM-IV diagnosis EDNOS needs to be considered in studies of the prevalence and course of eating disorders.