I would consider it like bread.

> a physical dependency

Was it their fault in the first place? i.e. did they start using it for a good reason and are now dependent? Or did they start using it because they like how it feels?

> What if it's life critical

Like bread.

You are being a bit too simplistic - the specific details don't matter, what matters is the person's state of mind. Is he stealing because he does not care about the other person, and only about his own enjoyment? Or is he stealing because he has truly no other choice and he feels bad about it?

It's impossible to really know someone else's mind, all you can do is judge based on behavior.