Man has this annoying tendency not to believe facts unless they are experienced directly. You can tell teens what you want and they will still do what they want, especially if they know you did the same and ended up alright.

I agree that honesty is the best policy, teenagers can smell hypocrisy from miles. Another good policy is to make experimentation safe, so everyone can make his or her mind up without risking potentially fatal or life-altering contact with the worst elements of society.

I personally think public education should also have a dedicated subject on the topic of addiction, be it to drugs, food, gambling, videogames, and whatnot. An economic system based on profit will inevitably thrive on addiction, often at the expense of public health. Surviving contact with addictive impulses is a life skill that gets more and more essential every day.