I think that is very symbolic, our professional care givers understand and we trust them; so why not family/friends. Someone may not understand our experiences and trauma that caused PTSD because they have not experienced it themselves. But it does not mean that they can not try to understand how PTSD has changed us and what PTSD is, in order to help them change and learn to live with our new lives. Other wise, you isolate yourself from those that just want to help and care for you. Psycho-education amongst family and friends is very important, if they don't understand; they won't be able to live with you and then you will be alone. I've seen many families torn apart by negative isolationist thoughts of someone adapting to life with PTSD.