In any situation, we take action if we believe that we can influence the outcome of the situation through our action.

If we do not believe that we can influence the outcome, we prefer inaction.

Irrespective of what we believe, it is almost always the case that we can influence the outcome of a situation that we are in. At least in small ways.

Focusing on those little changes we can bring about and taking action towards them is how we make progress - in everything from losing weight to recovering from a traumatic experience. 

What we need is to re-instil the sense of belief. And hope.