Thanks for the reply, dragonfly.

What concerns me is that people talk of "episodes" of DP and DR, whereas my feeling of derealisation is almost constant, like a brainfog. I don't notice it when I don't think about it, but on some days, perhaps when I'm down, worried, tired or stop to think about it for too long, it gets bad. Speaking of greying out, come to think of it, when I "defocus" my eyes and stare off into space, it often feels as if all the colour is fading from the environment until I "refocus" them and snap out of my trance, so to speak.

As for pot, nope, I've never done it. My dog, when this happened, would have been 4 years old and was in perfectly good health. I asked my psychotherapist about all this, i.e. "Why then?" and she said that it wasn't necessarily a cause and effect thing. I talk about it in the "Anxiety, Phobias" forum, but I have a serious problem with hypochondria, and around this time, I was really worrying about being seriously ill. (I wasn't. As usual. :P) As you say, DR can result from anxiety, so maybe that's it.

Indeed, I don't really feel anxious all the time, but a lot of my thoughts are negative, cynical or fatalist. There aren't many moments when I genuinely panic, but I zone in on the slightest ache or pain and worry about it, and this is a daily occurrence. When I had this examined by the doctor when the DR first occurred, she said I was essentially high on adrenaline, that my heart had not stopped beating at a hundred miles a minute since I first walked in her door. My psychotherapist later said that our biochemical goings-on can be put out of sync or altered negatively to keep the "fight or flight" response going; it all becomes normal as opposed to abnormal.

It often feels like this brainfog-like DR is a physical thing, as if I could reach into the back of my head and literally pull it out. I had an MRI which revealed nothing more than mildly inflamed sphenoid sinuses (and my doctors all think this is something that's basically "one of those things"). A recent blood test and an eye examination earlier this year showed nothing sinister.