There is an interesting question in there, of whether what is termed depression in general and in PTSD in particular, is one state or several different internal states that all look similar from the outside.I guess I just assumed everybody who suffers from PTSD also experiences depression to some degree.
Arguably, what a lot of us with long term traumas and early traumas experience is a state of learned helplessness and loss of self agency, we are not down so much as triggered into a state from the past in which resistance was counter productive or futile, often that is accompanied by hyper arousal with raging stress hormones, anxiety and physical states associated with massive stress arousal and activation of the sympathetic nervous system; tense muscles perhaps even going on to fibromyalga, stomach churning and acid reflux, tight chest and high blood pressure perhaps even difficulty breathing, constipation and possibly irritable bowel, and a mind that races away trying to find ways out
Tied in with that is the impossibility to make plans - because when you are in that state, immediate escape is the only priority your brain has.
In the extreme of triggering or stress, the parasympathetic nervous system (which normally relaxes the systems once the danger has passed, that the sympathetic nervous system had activated) shuts everything down,we dissociate and go limp like a rag doll, there's a good chance of our bowels and bladder emptying, that's a survival trick for when our ancestors were captured by a predator, to fool the predator that we were already dead and so didn't require a killing bite or killing blow to finish you off. Ive gone like that a few times, normally while getting the crap beaten out of me - literally.
I'm not sure how frequent a "depressed" depression is, but what gets called "depression" in PTSD, isn't - it's a state of learned helplessness, or of exhausted long term hyper arousal.
_________________
I'm currently reading this http://www.bookdepository.com/Neuro...elopmental-Trauma-Sebern-Fisher/9780393707861
If the results are widely replicable, then it seems to offer the possibility of a quick route to calming the limbic system, and allowing you to make gains in therapy. It's still considered "alternative" but then it does have to compete with big pharma and it's marketing department budgets of £billions
As soon as I get my job situation and finances straight, I'll be giving it a go.