Can you get her drug tested? Weed will stay in her system for about 4 weeks. Meth, cocaine, benzos and many other drugs...3 days. If she has a physical coming up, ask the nurse privately to do the test.
Monday's seem to be the best day...if they have used over the weekend, it will show up. If she sneaks out, runs away, or becomes ungovernable, call the police. It will leave a paper trail. Most the time they will pick up, do an assessment, possibly drug test, and release to parents.
After 2 or 3 times, they get to go to juvenile court and sometimes gets community corrections and for social services to get involved.
Read up on fetal alcohol symptoms. You really don't know for sure if and how much might have been used. What about her bio parents medical history? Any mental illnesses?
You can also Google your "state and SED waiver" which might help get her extra services that aren't covered by your insurance. It is based on the child's income, not yours.
I don't have time to go into how I learned all this stuff... Long story...
Ksm