Hallucinogens and dissociative drugs are both categories of drugs that alter a persons' state of mind and mood. Hallucinogens can cause a person to hallucinate--that is to see, hear, or feel things that aren't actually real. Hallucinogens include LSD, Mescaline (Peyote), Psilocybin, and Psilocyn
(Mushrooms). Dissociative drugs, such as Ketamine or PCP, alter a persons state of mind and mood but do not cause a person to hallucinate. Dissociative drugs cause a person to detach, or dissociate, from his or her surroundings.