I don't have OCD, but I do have these kinds of intrusive thoughts. A friend of mine who does have OCD describes the same types of thoughts I have, but with an added intensity, ferocity, and consistency to them.
Has there been any research on what the causes of OCD are, and what the current thinking is with regards to treatment?
Exposure and response prevention (https://iocdf.org/about-ocd/ocd-treatment/erp), a form of CBT, has helped me a lot. I'm less familiar with other interventions.
In terms of causes, OCD is substantially heritable. I think this sentence from a recent review paper (https://pubmed.ncbi.nlm.nih.gov/34030745) summarizes what's known better than I can: "Despite significant efforts to uncover the genetic basis of OCD, the mechanistic understanding of how genetic and environmental risk factors interact and converge at the molecular level to result in OCD's heterogeneous phenotype is still mostly unknown."