Personally I think that it's a defense mechanism in the mind that is trying to protect us from overwhelming emotions. When we get our brain to give the all clear signal that's when it will be over. The reason this thing persists for so long is that day in and day out we ruminate over it. Fueling the fear in our mind. Your brain pretty much still thinks there is a threat. Not outwardly but internally. Once we stop ruminating and get on with our lives that's when we truly get better. I almost got out of it last month and to be honest with you I didn't really do anything special. I even ate everything I wanted. Now I'm set back because I let my anxiety and fears take control of me again. But I won't let that stop me from beating this thing.