disorder.
Prevalence
Twelve-month prevalence of bulimia ner vosa among young female s is 1%–1.5%. Point
prevalence is highest among young adults si nce the disorder peaks in older adolescence
and young adulthood. Less is known about th e point prevalence of bulimia nervosa in
males, but bulimia nervosa is far less common in  males than it is in females, with an ap-
proximately 10:1 female-to-male ratio. 
Development and Course
Bulimia nervosa commonly begins in adolesce nce or young adulthood. Onset before pu-
berty or after age 40 is uncommon. The binge eating frequently begins during or after an
episode of dieting to lose weight. Experiencing  multiple stressful lif e events also can pre-
cipitate onset of bulimia nervosa.
Disturbed eating behavior persists for at least several years in a high percentage of
clinic samples. The course may be chronic or intermittent, with periods of remission
alternating with recurrences of binge eating. However, over longer -term follow-up, the
symptoms of many individuals appear to diminish with or without treatment, although
treatment clearly impacts outcome. Periods of remission longer than 1 year are associated
with better long-term outcome.
Significantly elevated risk fo r mortality (all-cause and suic ide) has been reported for
individuals with bulimia nervosa. The CMR (c rude mortality rate) for bulimia nervosa is
nearly 2% per decade. 
Diagnostic cross-over from initial bulimia ne rvosa to anorexia nervosa occurs in a mi-
nority of cases (10%–15%). Individuals who do experience cross-over to anorexia nervosa