Diagnostic crossover in anorexia nervosa and bulimia nervosa: implications for DSM-V.

OBJECTIVE: The Diagnostic and Statistical Manual of Mental Disorders (DSM) is designed primarily as a clinical tool. Yet high rates of diagnostic "crossover" among the anorexia nervosa subtypes and bulimia nervosa may reflect problems with the validity of the current diagnostic schema, thereby limiting its clinical utility. This study was designed to examine diagnostic crossover longitudinally in anorexia nervosa and bulimia nervosa to inform the validity of the DSM-IV-TR eating disorders classification system. METHOD: A total of 216 women with a diagnosis of anorexia nervosa or bulimia nervosa were followed for 7 years; weekly eating disorder symptom data collected using the Eating Disorder Longitudinal Interval Follow-Up Examination allowed for diagnoses to be made throughout the follow-up period. RESULTS: Over 7 years, the majority of women with anorexia nervosa experienced diagnostic crossover: more than half crossed between the restricting and binge eating/purging anorexia nervosa subtypes over time; one-third crossed over to bulimia nervosa but were likely to relapse into anorexia nervosa. Women with bulimia nervosa were unlikely to cross over to anorexia nervosa. CONCLUSIONS: These findings support the longitudinal distinction of anorexia nervosa and bulimia nervosa but do not support the anorexia nervosa subtyping schema.

Should bulimia nervosa be subtyped by history of anorexia nervosa? A longitudinal validation.

OBJECTIVE: To determine whether a past diagnosis of anorexia nervosa (AN) predicts longitudinal course and outcome among women with bulimia nervosa (BN). METHOD: A subset (n = 176) of participants in the Longitudinal Study of Anorexia and Bulimia Nervosa who met DSM-IV criteria for BN either at study intake (n = 144) or during follow-up (n = 32; 4 had restricting AN at intake, 28 had binge/purge AN at intake) were included in this report. Over a median of 9 years, weekly eating disorder symptom data were collected from participants using the Longitudinal Interview Follow-up Examination, Eating Disorders Version. RESULTS: While there were no between-group differences in likelihood of partial recovery, women with BN who had a history of AN were more likely to have a protracted illness, relapsing into AN during follow-up, compared to those with no AN history who were more likely to move from partial to full recovery. CONCLUSION: Lifetime AN is an important prognostic indicator among women with BN and these longitudinal data would support the subtyping of BN on the basis of AN history.