Hallucinations involve sensing things – whether visual (sight), auditory (hearing), olfactory (smell), or gustatory (taste) – while awake that appear to be real, but instead have been created by the mind.
Common hallucinations include:
Feeling bodily sensations, such as a crawling feeling
Hearing voices (the most common type of hallucination). The voices heard may criticize or compliment the individual or they may be neutral in tone. Voices heard have also been known to command the individual to do something potentially harmful.
Seeing patterns, lights, beings, or objects
Smelling a foul or pleasant odor
In some cases however, hallucinations may be normal. For example, as part of the grieving process it is possible that one can hear the voice of, or briefly see, a loved one who has recently died.