By Dr. Sage Hawn, PhD, Licensed Clinical Psychologist at CAYA Care
Scientists have known for a long time that some mental health problems run in families. This led them to study families and twins to find out how much these problems are caused by genes. The Human Genome Project mapped out all the genes in humans, which has helped scientists better understand how genes affect our behavior. This has led to psychiatry and genetics working together more closely. In this article, we want to give a quick explanation of how genes and trauma are related. We hope this information will be interesting and helpful to people who don’t know much about genes and mental health. We want to show how studying genes can help us understand trauma better, even for people who might not believe it at first.
Studies show that our genes can affect how we respond to traumatic experiences. Scientists have looked at tiny changes in our DNA called single nucleotide polymorphisms (SNPs, pronounced “snips”) to learn more about how genes might influence things like PTSD. SNPs are common and happen when one tiny piece of DNA is different from person to person. These changes can help explain why people who go through similar traumatic events can have very different reactions.
Scientists are trying to figure out why some people are more affected by traumatic events than others. They study our genes, which are like instructions that tell our bodies how to work. One way they study genes is by looking at SNPs that can affect how we respond to trauma. They do this by looking at specific genes that they think might be related to trauma. But this approach has some problems, like not always getting consistent results and not considering the combined effects of multiple genes on trauma outcomes. In other words, there is no one “PTSD gene”.
Researchers have made progress in understanding how genes can affect mental health problems like PTSD. They used to look at specific genes, but now they look at all the genes in a person’s DNA to see which ones might be connected to PTSD. This approach is called a genome wide association study. It helps scientists find specific parts of a person’s DNA that might be linked to PTSD. But these connections are often small and hard to prove.
Scientists have found that the small effects of individual genes on the risk for PTSD add up to a bigger effect when you look at all the genes together. This helps to predict who might be at risk for developing PTSD or other trauma-related problems. By looking at all the genes, scientists can also better understand how genes and the environment interact to affect a person’s risk for PTSD. They are testing whether people with a higher genetic risk for PTSD are more likely to develop the condition when exposed to certain types or amounts of trauma.
Another way scientists are studying genes and PTSD is by using a fancy method called genomic structural equation modeling, or gSEM. This helps scientists estimate how much genes contribute to a certain problem, like PTSD, and how they are related to other problems that often go together with PTSD, like depression, for example. This method is becoming more popular as scientists learn more about how different mental health problems are related to each other. Some studies have used gSEM to see if PTSD and other problems like drinking too much alcohol have similar genetic risk factors (turns out, they do!).
In addition to studying how our genes affect our chances of having PTSD, there are other ways to learn more about how our genes are influenced by our environment to predict PTSD. Even though our genes stay the same throughout our lives, things in our environment can affect how they work. This is called “epigenetics.” Understanding how epigenetics affects PTSD is important because trauma and genetics can work together to cause it. How our body reacts to trauma is important in deciding if we will have a good or bad reaction to it. This shows that experiencing trauma is important, but it is not the only thing that causes PTSD.
As we learn more about how genes and the environment affect our behavior, we realize that it’s not just nature or nurture that matters, but how they work together. Instead of asking if genes or the environment are more important in causing PTSD, we are now asking how they interact to affect our response to trauma.
