My opinion is that a combination of therapy which incorporates regression(1) and targeted supplementation
after a careful assessment for neurotransmitter imbalances (2) would be a wise approach.
Some of the OCD foundation issues include doubt, guilt, addiction, living mostly in the past and/or future...
Working on everyone of these with the therapist will help, but it will take time to tame this beast.
Please don't fall in the trap of engaging your friends and relatives into this very aggressively, as you may be alienating them-they are not therapists after all- and you definitely don't want to lose their support.
The majority of OCD sufferers have high histamine and are *undermethylated.
Conventional doctors know very little about this.
I met a fellow on vacation in Mexico back in March and he happened to be a medical doctor and the director of a medical school in the Caribbean. When the subject of MTHFR gene mutations and *methylation arose, during our conversation, I realize that this is something he was not familiar with and not even taught in medical schools, yet affects, so many people suffering (unnecessarily) from a great number serious chronic conditions associated with this mutation.
The treatment to correct undermethylation is not that complicated and it involves usually OTC supplements and it's inexpensive! Go figure!
It best though to see a natural practitioner knowledgeable in this field.
I hope this helps,
Niko