Who is affected by schizophrenia

Schizophrenia affects almost 1% of the general population—or 1 out of every 100 people.1 It usually appears in late adolescence or the early 20s, although it can first appear in the mid-30s. It is rare for schizophrenia to occur prior to age 10 or after age 40, although it does happen.

Schizophrenia is found equally in women and men. It often emerges earlier in men (teens to 25 years) than women (ages 25 to 35). Schizophrenia may run in families (genetic disorder), although people with no family history can develop the disease.

A person born in a city is at a higher risk for developing schizophrenia than a person born in a rural area.1 Also, people born in the winter and early spring are more likely to develop schizophrenia than people born in the late spring and summer.1 One theory used to explain this risk factor is that schizophrenia may be linked to a common winter or early spring viral infection; the virus may interfere with brain development in an unborn baby.

New studies indicate that the risk for developing schizophrenia also increases if a father was over the age of 50 when his baby was conceived.2

For unknown reasons, people with schizophrenia who live in less developed countries have a better outcome with this disease than those living in developed countries.3 One thought is that people in underdeveloped countries have more family support available, have fewer outside demands, and their behaviors are more readily accepted by their communities.


  1. Sadock BJ, Sadock VA (2007). Schizophrenia. In Kaplan and Sadock's Synopsis of Psychiatry, 10th ed., pp. 467–497. Philadelphia: Lippincott Williams and Wilkins.
  2. Byrne M, et al. (2003). Parental age and risk of schizophrenia. Archives of General Psychiatry, 60(7): 673–678.
  3. Ho BC, et al. (2003). Schizophrenia and other psychotic disorders. In RE Hales, SC Yudofsky, eds., Textbook of Clinical Psychiatry, 4th ed., pp. 379–438. Washington, DC: American Psychiatric Publishing.

Last Updated: August 28, 2008

related physicians

related services

Bon Secours International| Sisters of Bon Secours USA| Bon Secours Health System

This information does not replace the advice of a doctor. Healthwise disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use. Privacy Policy. How this information was developed to help you make better health decisions.

© 1995-2010 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.