Nobody starts of planning to get addicted. And while they certainly should realize that's a risk I'm not sure it ever factors into anything. Much like harsh punishments don't actually deter crime.
Sometimes we take decisions without being fully aware of the consequences (or simple choosing to ignore the consequences), but this doesn't make us less responsible. Nobody drives intoxicated planning to have an accident, for example.
And of course punishments deter crime. Not the crime that happens, obviously, but the crime which is never committed. There would be more rape, theft and murder if there were no consequences at all.
And of course punishments deter crime. Not the crime that happens, obviously, but the crime which is never committed. There would be more rape, theft and murder if there were no consequences at all.