You know, I couldn't quite tell you. The changes I've had, I have a number of things I could think to attribute them to.

I can say, it's put some space between me and some of my no-drugs/alcohol type friends who don't know I do it, as we quit relating as much. If anything it actually makes me work harder, as I quit stressing so much when I'm high. However, if I begin to do it too much it does lead to me not caring as much, hence doing less.

It's all about balance.