Replying to I think my friend is on drugs.

I went over to my friends house yesterday to go mountain biking, and when i got there he looked kind of spacey. He had his bike and stuff ready, but he ran up to his room to get something. I heard him fumbling around for something for about a minute. When he came down the stairs, he was stumbling. Definitely not just stoned or drunk, and acting really weird. I went into his room later, and I saw under his bed there are these big plastic containers, and the whole room has kind of an earthy smell. Any idea what he could be on? I've tried asking him but he just blows me off. I'm getting kind of worried.