Dope is absolutely an ambition killer. I've never seen anything so effective at turning a productive person into a zombie.

But then, there's lots of other things that are real ambition killers - specifically, welfare benefits, and we've legislated those as a supposed social good.

I want all public assistance for able-bodied people removed unless they've done something to earn the benefit (eg, veterans' benefits). A doper would be classified as able-bodied if they can put one foot in front of the other and pack a load. If he can work, then he has to work to make money for his Cheetos. 

Hunger was a very useful motivator for me. Hunger made me who I am now - going into my fourth career in life, when I have more than enough loot to sit on my white-as-typing-paper buttocks for the rest of my life and do nothing. Why? Because I remember what it is like to be hungry.

Besides, looking around this country, there's more than a few people who could benefit from missing a few dozen meals...  as one of my farming friends in Nevada used to say: "what this country needs is a good starvin'."