Above: In PTSD, re-experiencing refers to intrusive thoughts, nightmares, and flashbacks of the traumatic event. Research based on VA’s Million Veteran Program has now pointed to the genetic underpinnings of these symptoms. (Photo for illustrative purposes only. ©iStock/tommaso79)
A VA Million Veteran Program study identified locations in the human genome related to the risk of re-experiencing traumatic memories, the most distinctive symptom of posttraumatic stress disorder.
Researchers from the VA Connecticut Healthcare System, Yale University School of Medicine, the VA San Diego Healthcare System, and the University of California San Diego collaborated with colleagues on the study of more than 165,000 Veterans.
The results appeared in the journal Nature Neuroscience.
PTSD is usually considered to have three main clusters of symptoms: re-experiencing, avoidance, and hyperarousal. Avoidance and hyperarousal are common to other anxiety conditions as well, but re-experiencing is largely unique to PTSD. Re-experiencing refers to intrusive thoughts, nightmares, and flashbacks.
The researchers compared the genomes of 146,660 white Veterans and 19,983 black Veterans who had volunteered for MVP.
The study revealed eight separate regions in the genome associated with re-experiencing symptoms among the white Veterans. It did not show any significant regions for black Veterans, considered separately as a group, because there were far fewer black study participants available, making it harder to draw conclusions.
Results were replicated using a sample from the UK Biobank.
The results showed genetic overlap between PTSD and other conditions. For example, two genes previously linked to schizophrenia and bipolar disorder were implicated. This could mean that the hallucinations experienced in schizophrenia may share common biochemical pathways with the nightmares and flashbacks of people with PTSD.
The study also revealed genetic links to hypertension. It is possible that hypertension drugs that affect these same genes could be effective for treating PTSD.
Taken together, the results “provide new insights into the biology of PTSD,” say the researchers. The findings have implications for understanding PTSD risk factors, as well as identifying new drug targets.
To read more about this study, visit VA Research Currents.