I think my friend is plauged by a demon?

I'm agnostic, but I pray for things roughly 3 or 2 times a week. My best friend has been different lately, crazy, even. But I didn't realize anything was wrong until today, when she said she saw neon shapes and colors, and heard a low demonic voice named Irritum(e?). She recently was forced from some narcotics she took, so that might be it but I'm not too sure about that part. She's even been unsure if God was real, and so that worried me. What should I do? Please keep in mind we're 13.