Schizophrenia Risk Factors: What Ups the Risk of Schizophrenia?

While there is no known direct cause of schizophrenia, many factors are known to increase the risk of schizophrenia. Some schizophrenia risk factors occur before a person is even born, while others are what are known as psychosocial risk factors – or those that are part of one’s psychology and life. No single risk factor causes schizophrenia but when added together, risk factors can come together and manifest the mental illness.

Prenatal Schizophrenia Risk Factors

Many risk factors for schizophrenia take place in utero or before. The number one risk factor for schizophrenia is family history. If a person has a first-degree relative with schizophrenia, their risk of having the illness is between 6% to 13% except in the case of twins where the risk of schizophrenia is about 17% for fraternal twins and almost 50% for identical twins.¹ The presence of epilepsy in the family history also increases the risk of schizophrenia. (More on schizophrenia genetics)

Other known schizophrenia risk factors that occur before birth include:²

• Lead and other toxin exposure during pregnancy
• Exposure to some illnesses and parasites (like the toxoplasmosis parasite) during pregnancy
• Malnutrition during pregnancy
• Having an older father
• Birth complications
• Being born during winter months
• Abnormalities in the brain

Additional Schizophrenia Risk Factors

Once a person is born, there can be additional risk factors for schizophrenia. Again, each risk factor does not lead to schizophrenia directly, but is known to correlate to a higher chance of getting schizophrenia.

Additional schizophrenia risk factors include:

• Living in a city in a more developed country
• Drug use
• Highly traumatic or stressful events in childhood
• Drop in childhood IQ
• Having obsessive-compulsive disorder (OCD)
• Being left-handed

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