It happened to me one of the few times I tried pot. I don't know where the boy I was with got the pot, but it wasn't just pot and boy said, "Maybe it's laced with heroin."
Some people, predisposed to mental illness, get mentally ill as a result of the pot. Nobody knows if the pot kicked up what would have gotten there anyway or if it is the reason. I have mental illness and pot is poison to me. I have very strange and strong and scary reactions to pot...I tried it about eight times and, after experiences that were horrible and left me depressed and anxious and paranoid as all hello, I never touched the stuff again. Don't even like the smell around me so won't hang near adult pot smokers. Not that I know many.
The wrong idea that pot is harmless and not as dangerous as alcohol or cigarettes is going to be proven way wrong. Just like alcohol, it depends on the person's brain chemistry and if they decide to drive while high. I never could drive while high on pot.
But pot is going to be legal one day and, like alcohol, it will definitely not be seen as harmless once it is used openly. And one more gateway drug will be available to those who are vulnerable to addiction.