I have it for 10 years... derealization 24h/day is the worst symptom... uncovered some things in the last 2 years... feeling better for one year, but not cured, brain fog still present but not as strong as before.... what I have done: no gluten, no lactose/galactose, no bananas, no oranges (reacted the badest to oranges), no strawberries (peaches are the only fruit that I can handle.
In my opinion (regarding my case) the cause is either candida, or a sulphur metabolism problem, that gives me this horible brain fog (posible candida could be the cause of sulphur problem), and that's why I have all this food sensitivities
I will let you know at the begining of august if candida is the real culprit, as I'm following a strong treatment, and results must be visible until then.