I know a kid that is a bit at risk of this. The issue i see isn’t lack of discipline as much as it is lack of passion or motivation for anything. If you explore their desire for the future it is a complete blank. Nothing is interesting to them, the future just seems dark and grim, they are resolute about not having children and it feels like, to them, the world is committing slow-motion suicide and there’s no sense in getting emotionally invested in any particular outcome.