I'd would also like to add that often the drug abuse is used to medicate previously untreated mental health issues such as bipolar and borderline personality disorder.
I know several recovering meth addicts who were diagnosed with the above after they got clean.
That's why often it's so hard to diagnose those things early in abstinence because of the damage due to meth.
I self-medicated for a loooong time over clinical depression with meth, and that depression hit very hard after I got into recovery.
She really needs a thorough psychological evaluation, and if she's not honest about her drug use, it won't do much good.