These insurance pages should have a search feature where you can search to see what OCD-related injuries they cover. You may have to do some research on dozens of plans
On a more general note, I think employee insurance programs for super large, well-off corporations (consulting, accounting, etc.) tend to be really good. Probably because most of the people are young healthy and in shape and the programs are quite profitable for insurance companies; that's probably one of your best bets for an insurance that will cover OCD stuff
I have limited experience with this though so hopefully others can chime in..