Trust for adult child with addiction issues

I'm working with an attorney on a trust for my assets so that if I die while my adult child is still an addict not in recovery, money will come to her in supervised amounts over time. I don't want the trust to be punitive. I do want to make a provision to loosen some of the provisions if my daughter does choose a sober life, works at it and -- importantly --  maintains it over some period of time.  I'm sure other parents have dealt with this, and I'm hopeful that someone will be willing to share their approach.  I'm thinking along the lines of, if she's in recovery for, say, 18 months, with some sort of regular drug testing, and then an assessment by a psychotherapist and an addiction specialist.  Please feel free to contact me directly.