Obsessive-compulsive disorder (OCD) is a common psychiatric illness th
at occurs across the entire life span, Although most research on OCD p
ertains to adults, studies of the disorder in children and adolescents
have burgeoned over the last decade, A review of this literature sugg
ests that OCD has a bimodal incidence pattern, with one peak of onset
at approximately 10 years of age and another during adulthood, and tha
t the juvenile and adult forms are equally prevalent. Important simila
rities and differences between the juvenile- and adult-onset forms of
OCD can be seen: both show the same clinical phenotype, diagnostic nos
ology, and dose responsivity, but the early-onset disorder differs in
being clearly male preponderant, more highly familial, and associated
with a distinct pattern of comorbid psychopathology,, including disrup
tive behavior and specific developmental disorders. These findings hav
e implications both for clinical management and for future research, w
hich could consider age of onset as an important factor in studies of
all OCD patients.