If you are smoke weed when you are a teenager and then stop, then it will not affect your future much.
But if you are still smoking weed and take amphetamines later until you are 30, then you are likely to score low in a great many success factors including education, income, home ownership, relationship status, and reported happiness.
This is an Aussie study involving thousands of participants. Believe it or don’t believe it.
Come on folks, you already know this. Everyone knows the kid in high school who was a stoner and still is a stoner at 30 and no future to be had.