Friend doing drugs

[teenagersaaaaahhhh]

My Dds new best friend had a crappy childhood so I felt sorry for her even though my instincts said keep her away.
First I found out she used to do drugs, has attempted suicide in the past and apparently was nearly expelled for doing drugs at school. My Dd has admitted it's all true. She is still using (not just weed other stuff too).
I told my Dd she needs to seriously think about who she is getting involved with and that she can't come to the house.
I can't stop her talking to her at school and she is really upset because she really likes her and had a hard time with some of her friends.
Of all the people she could choose to hang out with it has to be her. I don't want her to stop telling me what's going on and banning friends usually back fires. Dd also has MH issues ATM so I don't want big arguments at home or her turning to this friend instead of us.

Help!

Please trust your mothers instinct and keep your dd safe. Your dd is now at very high risk of going down a similar path of drugs if her close friend is using. Teenagers brains are designed to be risk takers and their brains have not fully developed yet no matter how intelligent your dd might be.
Don't let temptation be right in front of her.
Put your foot down, explain your reasons to your dd and tell her she is not welcome in your home. You can tell her to still be civil to this girl in school but not to go out of her way to be hanging out with her.
Whatever excuses your dd has to use, tell her she must keep her distance.whether she does or not, you won't have full control but you can make it easier or harder for her and do not allow her to hang out with her outside of school, keep your dd too busy for hanging out untill this other girl gets bored and moves on to new friends

Thanks for the reply. The problem is if I ban her from the house she will start lying to go out and see her instead, at least if they are here I know what they are up to.
I don't think my Dd would try things at this stage but in the future who knows?
I can't lock her in the house and banning friends might just make her more determined to see her.
I'm hoping they fall out but atm that seems unlikely.
It's a nightmare

I can see why you're worried, but do you like the girl? Why not go the other way - accept the friendship and keep your DD talking to you about it by allowing the other girl into your house. Try and get to know her a bit - everyone deserves a chance.

Just found out it's prescription pain medication that this girl is taking.
If I tell the school safeguarding team what would happen?
Her room gets searched for drugs so her family must be aware.
I don't know how to keep her away from my Dd.
I talked to her about it and she got really upset saying she's her best friend. Having anxiety makes Dd more vulnerable to drugs if she's told they will make the anxiety stop.
Other than locking her in the house (which is obviously impossible) I don't know what more I can do apart from coming straight home after school but then I'm cutting her off from other friends at the same time. Worried about her MH if I do this, she might self harm

As you have said, you can't prevent her from seeing this girl, so your best bet is to educate your daughter.

Start having open conversations with her about the impact of drugs - what are they? Why do they make you feel good? What can go wrong? Talk about the side effects of drug taking, what they do in the body. Have conversations about alcohol and how that is also on the spectrum, talk about the legal consequences of drug taking. Watch films and programmes about it. Try not to take a moralistic "this is BAD" stance, but an informed, open discussion which will allow your daughter to feel she can talk to you about it. Talk to her about why this girl might do drugs, how it helps her escape but how it doesn't fix the root of the problem. Talk about risk taking behaviour and how drugs impair decision making. Talk about it all, as much as you can without bashing your daughter over the head with it.

You can't control what your daughter does, but you can make her really well educated and informed about it.

Good luck.

Thanks for the reply.
We have talked about all of those things but of course she's thinks it's a "lecture".
I'll keep having the discussions because I know she does listen. I'm worried she might be told it will stop her anxiety and at some point in the future she might try it.