When we're done
When the following description of the cause of OCDs at About.com is written about eating disorders:
What Causes OCD?
The old belief that OCD was the result of life experiences has been weakened before the growing evidence that biological factors are a primary contributor to the disorder. The fact that OCD patients respond well to specific medications that affect the neurotransmitter serotonin suggests the disorder has a neurobiological basis. For that reason, OCD is no longer attributed only to attitudes a patient learned in childhood--for example, an inordinate emphasis on cleanliness, or a belief that certain thoughts are dangerous or unacceptable. Instead, the search for causes now focuses on the interaction of neurobiological factors and environmental influences, as well as cognitive processes.