Interesting post! I became convinced that I had OCD because like you, I didn't have the handwashing thing but just the obsessive thoughts and fixations that I couldn't seem to shift. I am on an SSRI - Sertraline - because I was diagnosed with what my doc termed "chronic anxiety" and I am also seeing a psychologist. The latter didn't think that it was OCD although as she says, there is a spectrum and everyone on it is somewhere so maybe I am closer to having than not, if you see what I mean?

Anyway. I'm reading Ruby Wax's book about her battle with depression and she talks about her obsessions which are part of her condition. I think that all these kinds of mental conditions are linked and the fact that SSRIs are prescribed for depression, anxiety, OCD and PTSD would seem to support this.
I'm coming off my HRT because Sertraline is helping me plus the CBT I am doing. However, this is my choice and not what the doc has insisted on so it would seem you can take both at the same time. If Sertraline doesn't suit you, don't give up as there are other types. And I would recommend Ruby's book to you - a REALLY good read - she has done a qualification in mindfulness and I am going to start a group session on this in the New Year. Just remember, you are not alone and you can always come on here and let off steam. Take care
