What else was in the joint that made someone i know bad trip?

So someone i know had a weird experience after smoking a joint the other night, she said she was seeing spot-light like lights flashing and the room felt like it was moving. she felt numbness in her hands and feet and had a hard time focusing her sight. I've never experienced anything of the sort while smoking weed so i was wondering if anyone would have any idea what else could have been in the joint.