-Being drunk or high, or coming down from such drugs as marijuana, LSD, cocaine (including crack), PCP, amphetamines, heroin, ketamine, and alcohol
-Delirium or dementia (visual hallucinations are most common)
-Epilepsy that involves a part of the brain called the temporal lobe (odor hallucinations are most common)
-Fever, especially
in children and
the elderly
-Narcolepsy
-Psychiatric disorders, such as schizophrenia and psychotic depression
-Sensory problem, such as blindness or deafness
-Se