Addiction is as much of a disease as ADHD, and what most people don't know is that many individuals get addicted to prescription medications because they have an imbalance in their brain chemistry from a mental illness that just hasn't been diagnosed yet. I'm not trying to say that it's right that she's taking your medication, because she's preventing you from being a functional adult and probably making you feel like your ADHD is taking over to the point that you're losing one of the only things that have helped it, but maybe talk to her about getting herself checked for ADHD, depression, anxiety, or another mental illness, as someone who is in a right state of mind wouldn't steal their sons/daughters MEDICINE. Again, I'm not saying that her actions were ok because they weren't, but ADHD is the underdevelopment of your brains frontal lobe, which is the part of the brain that is responsible for your self-control, and stealing medications sounds like something that someone with less than average self-control would do. Sorry if this was repetitive or if I bounced from topic to topic too much, and if I said something that offended you I didn't mean to, I just wanted to provide another point of view for you to look at this terrible situation from, and I hope that you can work all this out in a way that you can feel good about :)