steroids. why?

I heard today on the news that Olympic gold medalist Marion Jones admitted steroid use prior to competing in the Olympic games. My question to everyone is ,why would a world class athlete like Ms. Jones have to use performance enhancing drugs? She was already the best in the world, who was she trying to defeat herself? Maybe I am not getting it but it seems that the lust for money and victory overshadow the need for good health and long life, neither of which can be assured by steroid use.
When the issue of steroid use by athletes comes up, it is usually coupled with concerns about cheating, I think it goes beyond that. Cheating aside, many of the athletes who use steroids are taking big risks for the sake of winning not knowing or caring that early death and a painful future may await them. I hope that Ms. Jones is ok and can reverse the effects of steroids and convince others not to use them regardless of performance results.