The legal stuff at least is "measured" and has testing (albeit often not enough/very good) behind it and you know the "amounts" and what's in it, etc. whereas the street stuff is just bad news and has its own side effects. You can't get something for nothing. If you don't want to be anxious and can't work fast enough in therapy to help, then there will be side effects but you won't be "high" just have the bad side effects. The problem too with most street drugs is one gets high and can't function as well (although if you are nodding off with the pdoc's that's not much better).