Post-traumatic stress disorder occurs after a person is exposed to a traumatic event, though not everyone that experiences or witnesses such an event is affected by the condition. New genetic research may now explain why some people develop the condition while others do not.
Researchers from the University of California in Los Angeles (UCLA) have identified two gene variants that could influence the risk of post-traumatic stress disorder (PTSD). This discovery could lead to improvements in the diagnosis and treatment of PTSD in the future.
“Many people suffer with post-traumatic stress disorder after surviving a life-threatening ordeal like war, rape or a natural disaster,” explains lead author Dr. Armen Goenjian. “But not everyone who experiences trauma suffers from PTSD.”
According to the National Institute of Mental Health (NIMH), 6.8% of the adult population of the US experience PTSD at some point in their lifetime. The condition can lead to several debilitating symptoms, such as:
- Avoidance of people, places or situations
- Intrusive memories
- Loss in concentration
- Negative changes in thinking and mood.
Symptoms can vary in intensity over time and can be triggered by reminders of the traumatic event that caused the disorder to occur in the first place.
Dr. Goenjian traveled to Armenia in 1988 after a 6.8 magnitude earthquake hit the country, destroying many cities and killing more than 25,000 Armenians. Around two-thirds of the dead were children.
A pair of psychiatric clinics was established by Dr. Goenjian and his colleagues to treat survivors of the earthquake for 21 years. During this time, many families agreed to have blood samples sent to UCLA so that the team could analyze their DNA for information pertaining to psychiatric vulnerability.
Previous research in 2012 involving these samples led to the discovery that survivors carrying two gene variants associated with depression were more likely to have PTSD than those that did not carry the variants.
For the study, published in the Journal of Affective Disorders, the team assessed the roles of two genes in the DNA samples, taken from 200 individuals. The genes were COMT, an enzyme that degrades the mood regulator dopamine, and TPH-2, a controller of the production of serotonin.
“We found a significant association between variants of COMT and TPH-2 with PTSD symptoms, suggesting these genes contribute to the onset and persistence of the disorder,” says Dr. Goenjian. “Our results indicate that people who carry these genetic variants may be at higher risk of developing PTSD.”
Dr. Goenjian says the team hopes that the study’s findings will lead to molecular methods for screening people at risk for PTSD and identify new forms of drug therapy to prevent and treat the disorder.
“A diagnostic tool based upon PTSD-linked genes would greatly help us in identifying people who are at high risk for developing the disorder,” he concludes. “Our findings may also help scientists uncover more refined treatments, such as gene therapy or new drugs that regulate the chemicals associated with PTSD symptoms.”
Despite their discovery, Dr. Goenjian is careful to state that PTSD is still likely to be caused by multiple genes. He recommends that research into this area continues in a bid to uncover more of the genes involved.
Anyone can be exposed to a traumatic event and be affected by PTSD, regardless of age and gender. “Researchers are studying the importance of various risk and resilience factors,” state the NIMH. “With more study, it may be possible someday to predict who is likely to get PTSD and prevent it.”
Recently, Medical News Today reported on a study finding that women experiencing large numbers of PTSD symptoms could have almost two times the risk of developing type 2 diabetes compared with women who have not been exposed to trauma.