Soma causes me to slur and act wierd. It's a muscle relaxer and I'm not sure how popular it is. I'm 23 myself.
So hard to tell what she might be taking. Are you sure she wasn't drinking? Like Vicki suggested, why don't you ask her. Not in a confrontational way, but in a supportive, we want to be here for you kind of way. How often do you see her? Can you keep track of it at all?
Hi~ Xanax has been around for a long time. It is an anti anxiety med with a secondary anti depression quality. I can't say,personally,what other drug to ask her about. Just ask what she's taking and tell her it's obvious she wasn't herself. But,if she's in trouble with pills,she needs to admit and take the control. Just support her.
All the best~
Vicki