What causes schizophrenia

It is generally agreed that schizophrenia is caused by a combination of factors rather than a single one.


Dopamine is a chemical that carries messages between nerve cells in the brain. There is evidence that dopamine is involved in the development of schizophrenia, but it is still not clear how, or whether this theory applies to everyone with schizophrenia. Antipsychotics, which are sometimes used to treat schizophrenia, target the dopamine system.

Stressful life events

Highly stressful or life-changing events may trigger schizophrenia. These include:

  • Feeling lonely or isolated
  • Being out of work
  • Having financial difficulties
  • Becoming homeless
  • Losing someone close to you
  • Being abused or harassed

Drug abuse

Some people may develop symptoms of schizophrenia after using cannabis or other street drugs, such as cocaine or amphetamines.

If you already have schizophrenia, using street drugs may make the symptoms worse. Drinking alcohol and smoking may also prevent medication from effectively treating your symptoms of schizophrenia.


Some families seem to be prone to schizophrenia, which suggests a genetic link to the condition. However, rather than there being a specific gene associated with the development of schizophrenia, it is thought that certain genes might make some people more vulnerable to developing schizophrenia, which could explain why some people in the same family may be affected but not others.

Other causes

Some studies suggest that physical differences in the brain, or injury to the brain, may be linked to schizophrenia, and these physical differences may occur before the person is born. Other possible causes, including viruses, hormonal activity (particularly in women), diet, allergic reaction or infection has also been suggested, and research into these other possible causes is ongoing.

Are some people more likely to be diagnosed than others?

About one in every hundred people is diagnosed with schizophrenia. It seems to affect roughly the same number of men and women. Most people diagnosed with schizophrenia are aged between 18 and 35, with men tending to be diagnosed at a slightly younger age than women.


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