adulthood, although males are more commonly affected in childhood. 
Development and Course
In the United States, the mean age at onset of OCD is 19.5 years, and 25% of cases start by
age 14 years. Onset after age 35 years is unusual but does occur. Males have an earlier age
at onset than females: nearly 25% of males have onset before age 10 years. The onset of
symptoms is typically gradual; however,  acute onset has also been reported.
If OCD is untreated, the cour se is usually chronic, often with waxing and waning symp-
toms. Some individuals have an episodic course, and a minority have a deteriorating
course. Without treatment, remission rates in  adults are low (e.g., 20% for those reevalu-
ated 40 years later). Onset in childhood or adolescence can le ad to a lifetim e of OCD. How-
ever, 40% of individuals with onset of OCD in childhood or adolescence may experience
remission by early adulthood. The course of OCD is often complicated by the co-occurrence
of other disorders (see section “C omorbidity” for this disorder).
Compulsions are more easily diagnosed in  children than obsessions are because com-
pulsions are observable. However, most childr en have both obsessions and compulsions
(as do most adults). The pattern  of symptoms in adults can be stable over time, but it is
more variable in children. Some differences in the content of obsessions and compulsions
have been reported when children and adol escent samples have been compared with
adult samples. These differences likely refl ect content appropriate to different develop-
mental stages (e.g., higher rates of sexual an d religious obsessions in adolescents than in