Are genes involved in schizophrenia?

Dear Reader,  

You’re not alone in wondering whether a family history of psychiatric disorder might impact your future children. While family history does increase the risk of schizophrenia, genetics are only one piece of the puzzle. Issues during pregnancy and environmental factors (such as stress, trauma, and substance use) are all contributors to schizophrenia risk. Additionally, there’s no one gene that causes schizophrenia. So, although it’s possible to do genetic testing, the results won’t be able to tell you the likelihood of whether you or a future child will develop schizophrenia.   

What is schizophrenia?   

Schizophrenia is a psychotic disorder that impacts about one percent of the population. It usually appears in people assigned male at birth (AMAB) from their late teens to early 20s and in people assigned female at birth (AFAB) from their late 20s to early 30s. Symptoms of schizophrenia vary person-to-person but could include:  

• Hallucinations (seeing things or hearing voices that don’t exist) 
• Delusions (such as strong beliefs about things that aren’t true) 
• Disorganized speech, thinking, and movement 
• Unusual behavior  
• Loss of interest in everyday activities and withdrawal from social life  

List adapted from the Mayo Clinic 

Can schizophrenia be passed down through genes?  

The short answer is yes—but being genetically related to someone with schizophrenia doesn’t mean that you or your child will absolutely develop the disorder. Since there’s not one single gene that causes schizophrenia, it’s more likely that the disorder results from many different genes interacting with each other. 

Some research suggests that people who have parents or siblings with schizophrenia have around a ten percent risk of having the disorder, while those with grandparents, aunts, and uncles with the disorder have around a three percent risk. That’s because schizophrenia is likely caused by a combination of many different factors, including:  

• A permanent change to the genes (called genetic mutations), which impact the production of certain brain chemicals. 
• Pregnancy and birth issues, including malnutrition while in the womb, low birth weight, and exposure to viruses and toxins while in the womb.  
• Significantly stressful or traumatic life experiences. 
• Use of psychedelic drugs as a young adult.  

List adapted from Mayo Clinic and Health Central 

Some research suggests that even if someone has a strong family history of schizophrenia, their actual risk for developing it is only moderately increased if they were born after a healthy pregnancy. There’s also evidence that avoiding substance use or developing health coping strategies can help reduce the likelihood of developing this disorder further.  

Is it possible to test your own risk for schizophrenia?  

Because the genetics of schizophrenia are complex and not definitive, genetic testing isn’t currently recommended for risk prediction. However, it’s possible to test for the presence of certain genetic mutations that have been associated with a higher risk of schizophrenia.   

That being said, your actual chance of developing the disorder can’t be calculated from a genetic test alone. If you decide to pursue genetic testing, you might consider working with a licensed genetic counselor, who can help you put your test result in the context of your environment and family history.  

Is it possible to undergo prenatal testing for schizophrenia risk?  

While it isn’t common to conduct prenatal testing for genetic mutations associated with schizophrenia risk, it is possible. You might consider visiting a genetic counselor that specializes in prenatal counseling to get support with this option. They’re experienced in helping prospective parents understand a future child’s risk of illness. To do this, they’ll likely take a detailed analysis of your family medical history. However, many counselors won’t provide a numerical risk, such as telling you that your child would have a certain percentage risk. There’s still a lot that isn’t known about what causes schizophrenia, so this can be hard to pin to a single number.  

Ultimately, genetic probability isn’t fate. Although genetics have been linked to the disorder, environmental factors like trauma, stress, and drug use are also important in determining whether or not someone develops schizophrenia. Working with a licensed genetic counselor might help you decide whether genetic testing is the right path forward for you and your future family.