My parents don't have substance abuse issues. There is a family history with some of my mom's family and I know as a kid she went through a lot because of her Dad's drinking. I wish it had been discussed more because I didn't realize that several of my family members were alcoholic.....perhaps making it a genetic thing.....I probably would have gone down the same road.
My brother and I are both alcoholic, my sister doesn't drink that often but has said that she can "feel it" inside of her.
I'm glad you could tell you parents and they were supportive! I have thought about how I would tell them. I know they love me and support me regardless but it hard enough to say it out loud, let alone to the two people I would never want to hurt or dissapoint.
Take care!