Course and Outcome of Anorexia
Nervosa and Bulimia Nervosa
PATRICK F. SULLIVAN
Accurate depiction of the course and outcome of a disorder is fundamental to its characterization. These are critical data for clinicians and researchers alike. “Course” refers to the temporal pattern of an illness from onset to subsequent recovery, partial recovery, nonrecovery, or death. “Outcome” describes the state of affected individuals at some specified time after the development of a disorder. Both can be assessed in multiple ways. The temporal dimension is integral to both course and outcome.
Imbedded within these basic definitions, however, are a number of vexing complexities, particularly when applied to anorexia nervosa and bulimia nervosa. First, there are fundamental uncertainties about whether the International Classification of Diseases (ICD-10) and Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) nosologies accurately characterize anorexia nervosa and bulimia nervosa. The experience in many eating disorder services is that a substantial proportion of individuals presenting for care have “subthreshold eating disorders” that do not quite fit the ICD-10 or DSM-IV criteria for anorexia nervosa or bulimia nervosa. (Chapter 30 discusses atypical eating disorders, including subthreshold and partial syndromes.) Second, the potential diagnostic overlap between anorexia nervosa and bulimia nervosa remains incompletely understood, thereby adding a further level of complexity. Third, “outcome” for anorexia nervosa and bulimia nervosa has to be defined across a number of relevant domains. Fourth, the extant literature complicates the task of characterizing course and outcome by often neglecting the temporal dimension and by relying on clinical samples (particularly since there is ample evidence of profound referral bias for both disorders).
To clarify the concepts “course and outcome,” Figure 40.1 schematically presents a partial set of possibilities. At some “premorbid” time, no one has anorexia nervosa or bulimia nervosa. At the “postonset” time, all cases of anorexia nervosa and bulimia nervosa have developed (depicted by the arrows from the premorbid “well” box to the postonset anorexia nervosa and bulimia nervosa boxes). Subsequently, at “follow-up,”