Sorry people, I've seen some misunderstanding in this thread of xenophobia and I am cursed with this compulsion to correct people.
Xenophobia is a fear of people of other nations and cultures. Not just people.

OCD is best broken by experience.
For example, I too used to scream my head off about open doors, but then the living room door frame fell apart, and not having the money at the time to repair it, I tried hanging sheets up over the gap, but it just kept making holes in the wood.
I still like doors shut, but after living like that for a few weeks I calmed down.
There's a patient I once worked with who was a clean freak, and we had to introduce dirt into her life as she was making all the other residents lives miserable. She got over it. As she was already institutionalised it was also easy to break her hand washing habit by denying her access to water (many taps in bathrooms in homes are lockable anyway, as a lot of patients will drink water to excess, to the point of killing themselves). After a fortnight of only being allowed to wash her hands after the toilet and before meals, she lost the urge.

OCD is really, really common.
Most people at some time in their lives will go through some kind of mental issue.
It makes sense really, we all get minor and major things wrong with our bodies, and so why not the same with out minds?