Is there a genetic test for schizophrenia?

Orchid offers advanced genetic testing for couples who want their child to have the best shot of a healthy life. “Genetics for Humans” is where we unpack how genetics impacts our everyday lives and the latest tools to help you build a healthier family.

What is schizophrenia and how does it impact individuals?

When people think about schizophrenia, they tend to think of mad geniuses or dangerous unstable people. However, the unfortunate reality is that the greatest danger individuals with schizophrenia pose are towards themselves. About 10% die by suicide and an even larger fraction attempt suicide at least once. They are also 2 to 3 times more likely to die early from physical diseases than the general population.

Schizophrenia disrupts thought processes, which can impact daily activities like dressing, showering, and making meals. Many resources describe the medical and psychiatric impact of schizophrenia (some included below). I particularly like this comic, which stigma-busts and graphically illustrates what it’s like to have a brain disorder.

How common is schizophrenia?

In the United States, it’s estimated that 1.5 million people have schizophrenia in any given year. Usually, individuals develop symptoms during adolescence to early adulthood. There are no significant differences between sex in the chance of developing schizophrenia, though males tend to have an earlier onset than females.

What causes schizophrenia?

You might be surprised to learn that schizophrenia is primarily a genetic condition; studies estimate that schizophrenia is about 80% heritable.

Here, we’ll break down what that means and make sense of what causes schizophrenia. Before we get to the genetics bit, it’s important to recognize that there is a combination of factors beyond genetics such as a person’s brain chemistry, exposures before birth, substance use that can trigger a psychotic episode.

Does schizophrenia run in families?

Evidence that schizophrenia tends to run in families comes from studies of identical twins since they share 100% of their DNA.

If one twin develops schizophrenia, the other twin has a 1 in 2 chance, or 50%, of developing it, too. This is true even if they were raised separately, meaning they had different environmental exposures, and the only common thread is sharing the same genes.

In the past, our best guess of the risk of developing schizophrenia is based on records of what we’ve observed happened in some families. This is known as “empirical risk.” For example, empiric data tells us that a child whose parent has schizophrenia has about a 10% chance of developing it.

Is there a single genetic cause for schizophrenia?

So we know there is a strong genetic component to schizophrenia. But is there a specific “Schizophrenia Gene” like the Huntington’s disease gene that explains it all?

Short answer is no, but there have been lots of discoveries leading up to what’s possible today.

Scientists have been looking for such a genetic signal for some time now. Over the years, there have been many discoveries, including specific genes encoding for the “messengers” between brain neurons that don’t work properly in people with schizophrenia. We also know that about 1-2% of individuals with schizophrenia have a rare genetic syndrome called DiGeorge Syndrome, which often causes other health issues like heart defects and cleft palates.

But what’s become increasingly apparent for the vast majority of people with schizophrenia is that there is no single genetic cause. The reality is more complex. To properly measure genetic predisposition to schizophrenia, you have to assess the whole landscape by looking at many genes and genetic markers combined.

Is there a genetic test for schizophrenia today?

Yes, it’s possible to measure your genetic predisposition to schizophrenia. This is different from a diagnosis however. Measuring predisposition tells you if based on your genes, you are more or less likely to develop schizophrenia than the average person.

Recent scientific developments allow us to better quantify the genetic basis of schizophrenia than we have been able to in the past. With advanced genetic testing at Orchid, you can get a sense of your genetic predisposition to schizophrenia and remove some of the guesswork on what you can pass on to your future children.

We’re not going to nerd out too much here, but here are the basics on how the science behind advanced genetic testing works. Statistical genetics compare the genetic makeup of tens of thousands of individuals diagnosed with schizophrenia (“cases”) with individuals without schizophrenia (“controls”). This analysis finds many genetic markers that show up more often in people with schizophrenia than the general population. In case you’re curious about diving deeper, the Psychiatric Genomics Consortium recently performed the largest molecular genetic study on psychiatric disorders, analyzing over 150,000 individuals.

What actions can I take based on the information from a genetic test for schizophrenia?

If your future child has an elevated genetic risk for schizophrenia, the risk of developing schizophrenia at some point in their life can be up to 5 times higher than in the general population.

The useful thing about your results is that if you identify certain genetic vulnerabilities that can impact your future children, you can potentially do something about it and mitigate these risks.

Key takeaways

Schizophrenia is a brain disorder that can have a devastating impact on the daily lives of individuals that have this condition.
Past family studies have shown that genetics plays a big role in the chance of developing schizophrenia.
Advanced genetic testing can now see if this genetic component to schizophrenia can be quantified for you and your family.

Resources

Orchid offers advanced genetic testing for couples planning on building their family. We use advanced tools and smart, caring humans to help you give your future children the best shot of a healthy life. Conceive with greater confidence and peace of mind

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Orchid Health supports open research data initiatives while abiding by the terms of use on all sourced genetic risk models and datasets. Orchid does not train mental health models from restricted raw datasets including but not limited to that of the Psychiatric Genomics Consortium.