The class of drugs known as dissociative drugs distort users' perceptions of sight and sound and create feelings of detachment - or dissociation - from their environment and from self. Although these effects are mind-altering, they are not technically hallucinations.

Two such drugs, PCP (phencyclidine) and ketamine, were originally developed as general anesthetics to be used during surgery. DXM (dextromethorphan) is a common ingredient in cough suppressant medications, but taken in high doses can produce mind-altering effects similar to PCP and ketamine.