How much do you reveal?

We had a friend over for Christmas dinner yesterday -- a fellow longtime, grizzled newspaper person -- and we got to talking about our youthful exploits.
When I was a kid, parents didn't talk to kids about drugs and alcohol; they just figured you knew it was bad.
My father did talk to me once, when I was 17 and just about to get my license. It was the don't-drink-and-drive lecture with a twist. He told me I would be grounded if he found out I had been drinking, but the punishment would be far, far worse if I drove drunk -- or if I got into the car with someone who had been drinking behind the wheel.
"Call me," he said. "I'll come get you and you'll be in some trouble, but you'll be in a lot more trouble if there's drunken driging involved. I'll kill you myself before you have the chance to die in a drunken-driving accident."
As a parent, my attitude about pot was pretty liberal because I was of the age when everybody smoked it and nobody believed it was addictive. People of my generation scoffed at our parents' hypocricy when they drank and told us not to, so we didn't want to do the same with our children.
A lot of us didn't know what to tell our kids. Should we admit we drank before we were 21 or that we smoked pot? Should we insist they do as we say instead of as we did?
I told my kids pretty much the same thing my father told me about drinking. I figured they'd experiment, so. I think I said something like, "I'll ground you if you've been drinking, but I'll rip your still-beating heart out of your chest if I catch you driving drunk or getting into the car with a drunk behind the wheel."
I know they didn't listen to me.
I became much more adamant about kids drinking and smoking pot after my younger son almost died from booze and drugs when he was 22. I learned a lot while he was in rebab.
First of all, the younger a kid is when he or she starts to drink, the more likely he or she is to progress to alcoholism. So that rite of passage -- the knee-walking-drunk prom and after-party -- are not harmless.
Pot is 12 times more potent now than it was in the 1960s. That means a couple of hits on a joint can knock a kid on his butt, and kids can become dependent on it.
So, it's good to talk to your kids, and you should let them know they can come to you and talk about anything.
Oh, and threatening to tear their still-beating hearts out of their chests is frowned upon these days.