I think less dramatic things have more of an impact. Kids see other kids drinking or doing drugs, and they aren't dying and ODing. Yeah, those things happen, but the really sinister effects of drugs and alcohol are more subtle (ask my alcoholic dad, who's never been arrested or gotten into a car accident in his life, but alcohol has made him a shell of who he could have been). I always rolled my eyes at all the anti-pot commercials with all the horrible things happening to pot smokers, but the one that stuck with me was this one where this boy (maybe 10 years old) is talking to the camera as he goes out to get the mail. He says his brother smoked pot and he never got arrested or killed anyone or any of those things. He takes the mail in and goes down to the basement where his brother, who looks intentionally loser-like, is sitting on the couch staring at the TV. He gives him his mail and the kid says, "He's never done much of anything." To me that had impact, because while most people who smoke pot won't kill anyone because of it, it totally kills your motivation to accomplish anything (except massive intake of junk food). So I would personally go with something more low-key and honest, less melodramatic.