Terrifying post-traumatic stress disorder (PTSD) flashbacks may be partially genetic, a new study by more than 165,000 US veterans suggests.
Scientists from two veteran hospitals, Yale University and the University of California, San Diego, found eight DNA regions that are common to many white male soldiers who are reliving their traumatic experiences.
Black and female soldiers did not seem to share these genes, but this may have been just a statistical problem because the authors say relatively few were involved in the study.
Between 11 and 20 percent of US soldiers serving in Iraq were PTSDs – and finding the DNA foundation could help predict who is at risk of developing the debilitating condition and how to treat those who do it.
PTSD develops between eight and 12 percent of US veterans – and a new study identifies eight genetic risk factors that can increase the likelihood of people reliving traumatic events
More than half of American adults experience at least one traumatic event in their lives.
Trauma can occur in the form of a car accident, a sudden loss or violence, to name just a few sources.
People in certain work areas, such as health care, run a greater risk of trauma, but perhaps not so much as combat soldiers, who have to risk their lives and often witness or suffer horrific violence in the line of duty.
Yet not all of these people develop PTSD, a debilitating, chronic mental illness.
PTSD is characterized by symptoms similar to those of anxiety, such as irritability, sleeping problems, jumping, volatility, withdrawal and generally working in a kind of fight or flight mode.
But PTSD patients also relive their trauma, a unique and particularly disturbing symptom of the condition that acts as an important diagnostic marker for this.
It is not clear why some people develop PTSD and are withdrawn in the grip of their trauma and others do not.
A lot of research has attempted to identify genetic markers for the condition, but this is a difficult task because of the shared symptoms – and therefore possibly shared DNA – with other psychiatric disorders.
So scientists from VA & # 39; s in Connecticut and San Diego, as well as UCSD and Vanderbilt, decided to sharpen the genes of only those veterans who had PTSD and reported flashbacks.
They compared diagnoses and symptoms with DNA samples from 166,643 American veterans.
White veterans – who formed the vast majority of the sample, with 146,660 participants – who had experienced trauma again as part of their PTSD often shared variations at eight locations in their genomes.
Of those eight locations, three had particularly strong associations with flashback-like symptoms, according to the study published today in Nature Neuroscience.
More importantly, the genes they identified in the PTSD-suffering veterans followed two patterns.
Some genes were linked to cortisol, the stress hormone.
Scientists know that cortisol plays an important role in PTSD, but it is not yet clear how the genetic variations change cortisol production or responses in people at risk for the condition.
"The body has certain ways to accelerate when there is a stressful situation, and part of it is the cortisol response," said co-author and Yale psychiatrist. Spencer Gelernter at DailyMail.com.
The second pattern showed interesting links with various psychiatric disorders that may be useful in working out how treat PTSD from different people.
A common gene variant in veterans with PTSD has also been associated with schizophrenia and disorders such as bipolar disorder, which can be accompanied by psychotic episodes.
& # 39; Medications used to treat schizophrenia – antipsychotics – have been tried in some patients with PTSD and the results so far have been negative or, the best we can say, is inconclusive. Gelernter from.
When someone with PTSD experiences a traumatic event again, they feel that it is all happening again – but they know that they are really just trapped in a lively, painful memory.
People who are schizophrenic or have a psychotic episode, however, lack this awareness. The strange event seems to them to be new and external, while in reality it is probably also traceable to their own experiences.
Dr. Gelernter and his team assume that & # 39; the main difference is awareness with PTSD and lack of awareness with schizophrenia, so these risk genes may be related to reliving & # 39 ;, he says.
With a better understanding of genetic risk factors for both schizophrenia and PTSD flashbacks – and the link between the two – doctors may be better able to determine which PTSD patients can benefit from these drugs, even if they are not schizophrenic.
This, of course, still needs to be tested, but it is a step toward using the understanding of the genetic risk that scientists are extracting from large datasets, such as the biobank with genetic data from the US Million Veteran Program in a clinical setting.
& # 39; We are fascinated by the genetics of this condition, but ultimately our goal is to provide better treatment for patients who have that problem, & # 39; said Dr. Gelernter.
& # 39; And we see a way in which we could lean in that direction with those results. & # 39;
. (TagsToTranslate) Dailymail (t) health (t) Iraq (t) California