Psychosis occurs when a person loses contact with reality. The person may:
- Have false beliefs about what is taking place, or who one is (delusions)
- See or hear things that are not there (hallucinations)
Medical problems that can cause psychosis include:
- Alcohol and certain illegal drugs, both during use and during withdrawal
- Brain diseases, such as Parkinson disease and Huntington disease
- Brain tumors or cysts
- Dementia (including Alzheimer disease)
- HIV and other infections that affect the brain
- Some prescription drugs, such as steroids and stimulants
- Some types of epilepsy
Psychosis may also be found in:
A person with psychosis may have any of the following:
- Disorganized thought and speech
- False beliefs that are not based on reality (delusions), especially unfounded fear or suspicion
- Hearing, seeing, or feeling things that are not there (hallucinations)
- Thoughts that "jump" between unrelated topics (disordered thinking)
Exams and Tests
Psychiatric evaluation and testing are used to diagnose the cause of the psychosis.
Laboratory testing and brain scans may not be needed, but sometimes can help pinpoint the diagnosis. Tests may include:
Treatment depends on the cause of the psychosis. Care in a hospital is often needed to ensure the person's safety.
Antipsychotic drugs, which reduce hallucinations and delusions and improve thinking and behavior, are helpful.
How well a person does depends on the cause of the psychosis. If the cause can be corrected, the outlook is often good. In this case, treatment with antipsychotic medicine may be brief.
Some chronic conditions, such as schizophrenia, may need lifelong treatment with antipsychotic drugs to control symptoms.
Psychosis can prevent people from functioning normally and caring for themselves. Left untreated, people can sometimes harm themselves or others.
When to Contact a Medical Professional
Contact your health care provider or mental health professional if you or a member of your family is losing contact with reality. If there is any concern about safety, take the person to the emergency room to be seen by a doctor.
Prevention depends on the cause. For example, avoiding alcohol prevents psychosis caused by alcohol use.
American Psychiatric Association. Schizophrenia spectrum and other psychotic disorders. In: American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. 5th ed. Arlington, VA: American Psychiatric Publishing. 2013:87-122.
Freudenreich O, Brown HE, Holt DJ. Psychosis and schizophrenia. In: Stern TA, Fava M, Wilens TE, Rosenbaum JF, eds. Massachusetts General Hospital Comprehensive Clinical Psychiatry. 2nd ed. Philadelphia, PA: Elsevier; 2016:chap 28.
Last reviewed on: 4/30/2022
Reviewed by: Fred K. Berger, MD, addiction and forensic psychiatrist, Scripps Memorial Hospital, La Jolla, CA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.