OCD can start at any time from preschool to adulthood.
Although OCD can occur at any age, there are generally two age ranges when OCD tends to first appears:
- Between the ages 8 and 12.
- Between the late teen years and early adulthood.
This is roughly the same number of people living in the city of Houston, Texas.
There are also at least 1 in 200 – or 500,000 – kids and teens that have OCD. This is about the same number of kids who have diabetes.
That means four or five kids with OCD are likely to be enrolled in any average size elementary school. In a medium to large high school, there could be 20 students struggling with the challenges caused by OCD. 
-  National Institute of Mental Health ↩
-  Ruscio AM, Stein DJ, Chiu WT, Kessler RC. “The epidemiology of obsessive-compulsive disorder in the National Comorbidity Survey Replication.” Molecular Psychiatry. 2008 Aug 26. ↩
-  March, J. & Benton, C. (2007). Talking Back to OCD. (pp.10-11). The Guilford Press. ↩