Psychotic disorders include severe mental disorders which are characterized by extreme impairment of a person's ability to think clearly, respond emotionally, communicate effectively, understand reality, and behave appropriately. Psychotic symptoms can be seen in individuals with a number of serious mental illnesses, such as depression, bi-polar disorder (manic-depression), schizophrenia, and with some forms of drug and alcohol abuse. Psychotic symptoms interfere with a person’s daily functioning and can be quite debilitating. Psychotic symptoms include delusions and hallucinations.

Delusion:
A false, fixed, odd, or unusual belief firmly held by the patient. The belief is not ordinarily accepted by other members of the person’s culture or subculture. There are delusions of paranoia (others are plotting against them), grandiose delusions (exaggerated ideas of one's importance or identity), and somatic delusions (a healthy person believing that he/she has a terminal illness).

Hallucination: A sensory perception (seeing, hearing, feeling, and smelling) in the absence of an outside stimulus. For example, with auditory hallucinations, the person hears voices when there is no one talking.