Psychosis (sy-KOH-sis) is a condition usually caused by mental illnesses in which a person has a difficult time thinking clearly, behaving appropriately, or understanding what is real and what is not.

More to Know

Psychosis is not a disorder of its own. It's more like a set of symptoms caused by a mental illness, brain disorder, brain tumor, or stress. In some cases, alcohol or drug abuse can also lead to psychosis.

Psychotic episodes usually include delusions or hallucinations. Delusions are false beliefs not based in reality, and hallucinations are sights or sounds that aren't really there. People with psychosis also may experience disorganized thoughts and speech, social withdrawal and isolation, reduced performance at school or work, and disturbed sleep patterns.

Psychosis often affects people in their late teens or early 20s, a stressful time in terms of social development and educational and work opportunities. A number of mental illnesses can cause psychosis, including schizophrenia, depression, autism, bipolar disorder, and personality disorders.

Treatment depends on the condition causing the psychosis, and often includes antipsychotic medications that reduce delusions and hallucinations and help improve thinking and behavior.

Keep in Mind

Many of the conditions that cause psychosis respond well to treatment with medications and therapy. Correcting the underlying condition is typically effective at treating the psychosis as well. Recognizing and treating the signs of psychosis early is the best way to prevent complications.

All A to Z dictionary entries are regularly reviewed by KidsHealth medical experts.