I would love to see some evidence to prove that point before admitting to the viewpoint, but lets for the sake of this argument say that you are right and that a mayority of the ex-jw´s get into some kind of trubles when they leave.
I´ve actually seen this kind of behavior with people that were and still are witnesses. They were held so hard by their parents, and as soon as they moved to their own apartments they started to live a life more like "normal" people, and in some extent even worse. It like a holding a spring really tense, when you let go, it springs loose rather violently.
The same principle is prob. accurate with alot of ex-jw´s. All those stupid things we should have done before the age of 25, piles up and we wanna experience life in its fullest as soon as we are free. For some that still are Jw´s but want out can also choose a destructive way, just because they can´t handle the preassure of leaving by their own accord. I know I almost did.
I think that a lot of people that seek religion have a need to belong to something bigger. Something to fill up the hole. Problem is that in some causes we don´t mind what fills the hole, as long as it is full. A lot of bad things happens because we "socialize" with the wrong people... That part, the wittness actually got right...
The psycological abuse of being df and shunned by all those that used to love you can be a hard blow to our minds. To be forced into solitute can make us do stupid things. Having no support, no friends and to be left without guidance leave us wandering a path we no longer have the map for.
Perhaps the witnesses got it right: Those that leave the organisation might get into some problems. The only reason why they are right is beacuse they create the cirumstances for the problem to arise