Psychosis is a mental and behavioral disorder in which a person has trouble telling the difference between what is real and what is not real. It may cause bizarre thoughts and behavior.
A person with psychosis may have:
Delusions, which are firmly held but false beliefs. Irrational suspicion of others (paranoia) is a common delusion. The person may think others are watching or trying to hurt or even kill him or her.
Hallucinations, which are false perceptions. Hallucinations can include seeing, hearing, feeling, smelling, or tasting things that are not really there.
Treatment for psychosis depends on the cause and may include care in a hospital. Medicines that diminish hallucinations and delusions and stabilize thinking and behavior are helpful. Group or individual therapy also may be helpful.