If I recall correctly the main lead in Secret garden suffers from PTSD. Although I am not sure that it is referred to as such, From what little I know it certainly appeared like that to me. Another one is Heart to Heart, in which both leads suffer mental distress but develop quite different symptoms post stress. And last but not least there is The Master's Sun, in which the lead character becomes emotionally detached and looses the ability to read after a horrific incident in his youth.
Just checked and saw that you have already seen both Secret Garden and The Master's Sun but thought I leave them on here just in case somebody else checks out this thread for PTSD dramas.