I have done South Beach a short time and Adkins ~ 6 months and had good results after I individualized it to my needs. One time I completely stopped eating carbs, both simple and complex, and experienced the dissociative state you describe. At first I thought it was part of my PTSD but I started thinking about going a week with no carbs whatsoever and ate a grilled cheese sandwich to see if some carbs would make me feel better. About 45 min later the dissociative state passed. I still like the Adkins diet but realize the need to include some complex carbs in my diet.