I used to have really bad ocd thoughts where I would hardly be able to do anything all day.. it was so bad. I would get ocd about anything, from sexual things, to religious topics, threatening thoughts, thoughts that all my bad intrusive thoughts may cause people harm, really mean intrusive thoughts about people, self harm thoughts, suicidal thoughts, the list goes on.
Oneday I got given a round of chanting beads and a bead bag, and everyday I chanted so many rounds on these beads and I found a dramatic improvement straight away and got better week by week with the odd upset but nothing like I had, had.
I would chant praise Jesus Christ on the beads and the Maha mantra. But I guess if you would like to try you could try chanting the name of God you are comfortable with. It was useful using the beads as if your mind tried to take you away you could say.. ' no i have to do so many rounds, only then can i finish'.
im just stating a technique which helped me.
Me chanting so many rounds everyday strengthened my mind, as my mind when chanting couldnt keep obsessing over things and became peaceful on the words after a while. Also I found through the day it acted as a strengthening agent to the mind so I found it easier to dismiss ocd thoughts if by chance they did come... or when they appeared I could start chanting to counteract the ocd thoughts,.
Maybe you can give it a go as it worked for me and I was an extremely bad case .. now I am not that bad... just have reocurring thoughts every now and then.
All the best