Inositol (of which the most prominent naturally occurring form is myo-inositol, cis-1,2,3,5-trans-4,6-cyclohexanehexol) is a carbocyclic polyol that plays an important role as the structural basis for a number of secondary messengers in eukaryotic cells, including inositol phosphates, phosphatidylinositol (PI) and phosphatidylinositol phosphate (PIP) lipids. It is found in many foods, in particular, in cereals with high bran content, nuts, beans, and fruit, especially cantaloupe melons and oranges. Inositol is not considered a vitamin itself because it can be synthesised by the body.
Myo-Inositol was classified as a member of the vitamin B complex (often referred to as vitamin B8), but was found to be synthesized by the human body (thus, declassifying it as a vitamin).
You can research on the Internet and find some of the research done with this compound. It seems to have almost as much effectiveness as SRIs but without the side effects.
It may be that OCD is more related to diet or physiological condition and thus more treatable with medication or diet.
I would suggest first taking a look at the medical / chemical side of things. If everything seems unresponsive, a look into the spiritual side of things might be recommended. A writer named Kurt Koch wrote about the effects of occult involvement which could manifest as forms of mental illness. He wrote at a time when these practices were diminishing and the effects were becoming less common. Now that more and more people are dabbling with the occult, these effects are going to be more common again.