If you could predict how well your clients might be able to deal with stress, just based on a blood or saliva
sample, would that change your treatment approach?
There’s a specific gene that’s been getting a lot of attention lately because it affects how the brain processes serotonin – a chemical created inside the body believed to be responsible for maintaining mood balance.
The serotonin transporter gene codes for a molecule that regulates the amount of serotonin signaling between brain cells, and it’s a key target for the treatment of mood disorders. It’s also well known for its involvement in clinical depression and posttraumatic stress disorder (PTSD).
And recent discoveries in epigenetics are indicating that changes to how the serotonin transporter gene gets expressed might be involved in a person’s brain response to threats.
Now, I’ve talked a little about what epigenetics is before, but here it is in a nutshell: There are tiny molecules called ‘methyl groups’ that can attach themselves to our DNA, and when this happens, they can change how a gene is expressed. Essentially, the methyl groups will regulate where and when a gene is active.
What makes epigenetics different from ‘classical genetics’ is that, while the genetic code of your DNA doesn’t get changed structurally, stress or other factors in the environment can cause chemical changes in your body. The environmental signals can trigger those methyl groups to park themselves on your DNA, affecting the way your genetic code gets read.
Researchers at Duke University knew that differences in the DNA sequence of the serotonin transporter gene seemed to give some folks exaggerated responses to stress (and seemed to play a role in depression). But they wanted to look at how epigenetics might be at work here.
Led by Ahmad Hariri, PhD, the researchers recruited 80 college-aged participants who are part of the ongoing Duke Neurogenetics Study (DNS) – a collaborative study that’s working to link genes, brain activity, and other biological markers that could indicate a risk for mental illness in young adults.
First they used non-invasive brain imaging to look at the amygdala of each participant while showing them pictures of angry or fearful faces and watching their responses. The amygdala governs how we respond to threat or stress.
Next, they measured the amount of methylation (how many methyl groups were present) on serotonin transporter DNA that they isolated from the participants’ saliva.
And they found a strong correlation between the amount of methylation and the amount of reactivity they saw in the amygdala. Plus, they found that the amount of methylation seemed to be a better predictor of amygdala activity than any other variation in the serotonin transporter gene.
But the researchers wanted to make sure that what they were seeing wasn’t a one-time thing.
They took a look at a different set of participants, this time 96 adolescents participating in the Teen Alcohol Outcomes Study (TAOS) at the University of Texas Health Science Center at San Antonio. Using the same methods as before, the group found an even stronger link between methylation and amygdala reactivity.
So, epigenetics could be playing an important role in whether or not we’re getting enough serotonin to the brain, and in turn, that could be affecting our moods or how we respond to trauma.
Now we do need to be cautious – this work is strictly correlative, and it’s all just getting started. The next step will be to find out how methylation directly affects the brain.
If you’d like to read more about the work of Dr. Hariri and his team, you can find the full study published in Nature Neuroscience, volume 17, pp. 1153-1155.
Eventually this work might help us predict mental illness, using saliva or blood samples to show us whether or
not genes for specific disorders are, or are not, expressed.
You can learn more about how epigenetics is involved in trauma and what that could mean for the way you approach treatment – click here for our courses on trauma.
So what do you think . . .
. . . if a tiny sample of saliva could help you better detect a client’s risk for something like posttraumatic
stress disorder, would you incorporate that into your treatment? And what sort of benefits do you think there might be from this? You can let me know what you think in the space below.