Question for the "My body, my choice" crowd.

In the abortion issue discourse, you can often hear the position of the Pro choice/ abortion rights people stated as "It's my body. It's my choice. The government can't tell me what to do with my own body". That is correct, right?
So, if that is your position, and this question is really only directed at those people, how do you feel about someone who wants to smoke crack or shoot heroin? Is it their body, their choice? Or is it different? If it is different, why is it different? I'm not trying to argue, I just want to know y'all's position. Same thing or not, and why.