A person can definitely get addicted to a lot of different things in that short period of time. However, I would first try to get her in for a medical workup. There are a lot of medical/psychological issues that can cause a behaviorial change.
If I was to approach her I would start with the medical because if you are wrong about the drugs...well, she might resent you. Just tell her you are concerned because she isn't acting like she normally does, tell her you love her and are urging her to get a medical work-up....just so you and quit worrying and she can find out if something is going on.
Now if you can get her to do that and nothing abnormal is going on you could stage an intervention with yourself, other family members and friends. Keep a journal and write down when her behavior changes, what time of day, what type of changes and the date. See if there is a pattern going on there.
My prayers will be with you
Yes.A person can addicted to almost anything in a few wks of regular use.What do u think shes taking?How has she changed?