It is a severe disturbance in which a person is unable to distinguish reality from fantasy.
Psychosis is considered a mental and behavioral disorder.
It results in a significant distortion of a person's mental capacity. The person has problems recognizes reality and relating to other people. These distortions are serious enough to interfere with the person's ability to deal with the normal demands of everyday life. Psychotic illnesses can have a physical or emotional cause. In general, there is no known way to prevent psychosis.