n. a false perception of something that is not really there. Hallucinations may be visual, auditory, tactile, gustatory (of taste), or olfactory (of smell). They may be provoked by mental illness (such as schizophrenia or severe anxiety disorders), personality disorders, or physical disorders affecting the brain (such as temporal lobe epilepsy sepsis, acute organic syndrome, or stroke) or they may be caused by drugs or sensory deprivation. Hallucinations should be distinguished from dreams and from illusions (which are based upon real stimuli).
Subjects: Psychology — Medicine and Health.