Hi Ghost,
I'm a carer not a sufferer so hope it is okay to reply to you.
My significant other has had ptsd as a result of combat and (I suspect) childhood cruelty.
When I first met him (prior to going to the army) he was the most controlled, handsome, charismatic man I had ever met. Years later he was a complete wreck, brain damage, broken nose, injuries a raging alcoholic coupled with insane violence.
It has taken a long time, but I have watched him grow from the depths of despair - disassociation, manic episodes, suicidal, reckless behaviour to not only improvement but also very long periods of stability.
He has not had a disassociation episode for years, he does not have mania anymore (and he doesn't take medication) he is no longer suicidal and although he still gets angry, he has not had a violent episode for a year (that caused him to be arrested at least)
His problem at the moment is trying to deal with all the issues that his previous, reckless behaviour caused and he still has problems with alcohol but... and this sounds a bit strange, he doesn't seem to be an alcoholic anymore either. He seems to now go from abstinence, to moderate drinking (usually when we spend a long time together) to alcohol abuse when stressed or out with his friends.
I sometimes think the ptsd has 'gone' and I am just dealing with the type of relationship problems everyone deals with... but, obviously, I know it is still there, he has brain damage so it isn't going anywhere.
He has never really had therapy either (only just started properly and had 1 session ) so that can't be the reason for the change.
I know ptsd cannot be cured but from my own experience it certainly changes over time and can diminish.
Hope this helps