I had this severely for a couple of years nearly daily about 5 years ago. Of course this is when I was diagnosed with General Anxiety Disorder, as derealization typically occurs in the presense of anxiety ( or is a symptom of)
Since I've been house bound with adrenal exhaustion, going on 2 years now I get it every once in a blue moon.....maybe 4 times in the last 2 years. One of those times is when I has a 2.5 lobster...the food highest in copper!! This was a sort of confirmation for me as far as the relationship between copper and anxiety/derealization goes.