Many children will develop OCD early, starting between ages seven and 12. In fact, most adults with OCD say their symptoms started when they were children. * OCD is more common in boys before the age of 12. After puberty, boys and girls are equally likely to develop OCD. * Over time, OCD symptoms can change. For example, your child might start out with excessive washing compulsions when he or she is young, but later develop excessive checking compulsions and stop washing in a compulsive manner.