I know more people who smoke weed than dont. And I dont know any homeless, unemployed or mentally ill people.Anecdotes are fun...
One of my buddies probably smokes 3-4 times a week and so does his wife, they're not much into drinking or anything else. They each own their own business and run them respectively, doing quite well. In fact he's down at USSA or shooting somewhere at least once a week. Which makes me jealous.
One of my clients is a real estate developer that I believe smokes every day, or at the very least pretty frequently. His last deal was for an 8 figure number, has 3 homes, several cars, a plane and he travels the country in what I call the rock star bus. 2 Million + bus with Ostrich skin walls.
On the flip side I could tell you about a number of people just like some of the others relayed, but I can't confirm that alcohol or harder stuff never came to into play.