There are several studies showing direct connection between heavy metal poisoning and OCD symptoms. A proper heavy metal test will shed some light on this but typically mercury and lead are major culprits.
There are dozens of ways to chelate, its all about picking the right one for your body, and slowly chelate the metals away without posing a bigger risk in your health. Examples of chelation techniques are aggressive ways like EDTA, DMSA to more natural approaches like chlorella, ndf, zeolite, cilantro, alginate, or a proper combination of these. Bottom line is to be patient and slowly remove these, while making sure your bowels and kidneys are working efficiently to properly remove heavy metals out.
Mike