Explanation for PTSD and depression

I am reading a book that I think might contribute the theory of how hypnosis works in therapy. The book is In an Unspoken Voice: how the body releases trauma and restores goodness by Peter Levine. It might be an explanation for PTSD and depression.

Everyone will have seen an instant induction, where the hypnotist startles the client by shouting or pulling them off balance. It has long been known that this is the result of the parasympathetic nervous system putting the client into tonic immobility. The person goes limp, their eyes roll up into their head, their breathing changes, they are impervious to pain.

Origin of PTSD and Depression

The Levine book explains this as being one of the five bodily reponds to danger. When danger appears our body first goes tense and alert, then tries to run away, or if it can't run away gets ready to fight, if that isn't possible then the body freezes motionless, and when danger is imminent the final stage is tonic immobility, the body flops and becomes helpless.

So instead the Flight or Fight responses, we should be talking about Flight, Fight or Flop. The book's argument is that when a person is frightened they go through the five stages. What is interesting is that the book claims that when the body is so frightened that we freeze, unless we are able to find a way to unfreeze the fear, the result is PTSD. According to his theory PTSD is result of not coming out of the freeze state. The therapy is therefore to help the client release the old fear.

How therapies work

This makes sense to me, and explains why relaxation, reiki, grounding, and yoga work to relieve mental stress by relaxing the body. It also offers a basis for understanding how metaphor therapy works.

Perhaps the five stage theory also gives a basis for understanding the cause of depression. Depression is triggered by learned helplessness. If the response to relentless pressure and fear is tonic immobility, then this explains where the depression comes from. I am only part way through the book and this link has not been mentioned yet, so I am reading on with anticipation.

What do you think?

How do you deal with PTSD? What do you think causes these things?