I don't know about the DSM but in the UK Complex PTSD has been around for a while particularly with treating children who have endured long term abuse. Therapy is the answer for PTSD and Complex PTSD although the therapy for the latter requires great sensitivity and generally longer. The belief being that if a child endures long term abuse that it alters cognition also and a core inability to trust. Also PTSD is not just an anxiety disorder, it usually has a whole bunch of symptoms with it that have come from trauma. Anxiety, depression and flashbacks.

Hugs all PTSD and complex PTSD is treatable although it may take a long time.