I believe any drug can ruin someone's life. Different people have different body chemistry and what might not affect one person much at all can be very detrimental to someone else.
My ex-husband was addicted to pot. I know the general consensus seems to be that pot is not addictive, but I'm here to tell you that my ex was addicted to pot. But then again, I know people who could take it or leave it. It really depends on the person.