I didnt mean to worry you, it is by no means certain how long it will be with you. The person who had their dp disappear over the course of a year as far as i can remeber was Martinelv, but I dont think he posts much here anymore (as far as i know) as he is dp free now.
As for the chemical processes going on, there are many theories as to what causes and cures is, we just dont know. Please dont panic about it, the more you think and worry about this the worst it gets!! Believe me!!
I am not the one to offer advice on which drugs help as i dont use them, but i know alot of people here will be able to help with that question
Sorry if this is scary