Cool! I learned a new term - "Highway Hypnosis". Thanks, Wild Coyote!

Really, mild dissociation is common regardless of whether or not a person has a mental illness, but as for more significant dissociative symptoms, I guess it's possible it may be more common in people with mood or emotional struggles. I think it often boils down to stress or other psychiatric struggles.

I wrote a blog post about my experiences with depersonalization and derealization, along with grounding techniques I've used to overcome them. Those experiences were ones I only had seriously for about a five year period. I really do believe I've overcome them. If you're interested in that post, let me know. I'm hesitant to provide links to my blog unless they are asked for.