Responsibilites...

Being a 7th and 8th grade PE and Health teacher, one of my primary concerns is how to make students realize that the decisions they make in their young lives can affect them forever. I have seen a major swing in 'jokes' made by students in regards to alcohol abuse, drug abuse, and sexual activity in the six years I have been teaching. I believe that a lot of these students think these things are "cool" but they do not realize the implications these activities could have in their lives. I have tried using examples, showing video clips, discussing the impact these things could have on their lives, etc. but it all seems to pass them by. It is as if the students do not think they will be affected. What can we do as educators to show the students what these things can do in their life?