Hello dgwaring,
So glad you found PsychCentral. I'm not sure I can offer much to you because I have a son who will turn 16 in December and honestly, he is a mother's dream. However, I was parented myself by some truly awful parents and was an undiagnosed bipolar II (we have depression primarily) and was a very difficult teen. I supposed because my parents were so bad at it (they were alcoholic and were simply not good at parenting) it gave me strong incentive the be the best parent I could be. I can tell you what worked for me and also, an impression I got while reading your post.
I agree with JerryMichele and others when they say that at her age, the people your daughter hangs around with are going to have a tremendous influence upon her activities. If her crowd smokes and drinks and has sex, then she will. How you will go about encouraging her to change this, I don't have any suggestions on it. Perhaps a therapist could help.
The one main thing I always did with my son from the age of 2-3, was to give him choices and consequences. For example, when he was 3, he got to choose what to wear between two different outfits. Then he got to choose what to eat, between two different vegetables, etc. This proceeded gradually his entire life and as he aged, every time he made a choice, he had to live with the consequences of that choice. With a teen your daughter's age, you can talk to her about the choices she's making. The choice to smoke, the choice to do dope, the choice to skip school, the choice to have sex, the choice to attempt suicide. Empower her. I don't mean to put her in danger. I mean to make her aware that these are things that she is choosing to do and there are always other choices, better choices and make sure that she always understands that the alternate choices might actually be more desireable based upon what she wants in her future.
The key is, get her thinking about her future. So many times, depressives don't think they have any future. With therapy and proper medication (if necessary) she will start to think about the future and she will start to realize that there can be a good future for her.
Having said all of this, there are also rules, house rules. They must exist for safety and consideration of other family members. And for the benefit of your daughter. My son has a set bedtime. He never, ever complained about it. That's because he learned in school that kids need a certain amount of sleep to be alert and perform well in class. That's all it took for him.
Like I said, maybe this is a PollyAnna view of your situation and I apologize if nothing here has helped. I do so understand how hopeless and scared and frustrated you must feel right now. I remember how it was when I was a teen. I was pretty bad.
I wish you the best in handling this difficult situation.