Hitting bottom is utter defeat combined with the inability to deny the true cause of that defeat. When the lofty fall and can blame no one but themselves, opportunity opens for constructive self-reflection and character growth.
Neurotics want to do the right thing and for things to go well as a result. They take it hard and are perhaps too quick to engage in self-reproach when things go wrong. Disordered characters, on the other hand, tend to take adversity in stride and blame everyone and everything else when bad things happen, even when those things really stem from their own actions.