Risk of PTSD may be in your DNA

By Brad Broker

Whether it’s caused by a military conflict, a sexual assault or personal loss, PTSD emotionally ravages some people while others feel no effect.  Turns out that certain people may be more prone to post traumatic stress disorders due to their DNA.

“We know from lots of data – from prisoners of war, people who have been in combat, and from rape victims – that many people exposed to even extreme traumatic events do not develop PTSD,” said senior author Karestan Koenen, professor of psychiatric epidemiology at Harvard T.H. Chan School of Public Health.

According to a new study published in Molecular Psychiatry, PTSD, “a disorder that by definition requires an environmental exposure, trauma—is also partly genetic in origin.”

“Before this study, not everyone was convinced that genetic factors make some people more prone to developing PTSD than others,” said study author Laramie Duncan, PhD, Department of Psychiatry, Stanford University. “Using a study of over 20,000 people and analyzing over two hundred billion (200,000,000,000) pieces of genetic information, we demonstrated that developing PTSD is partly genetic.”

Even though over 87 percent of participants had been exposed to some form of trauma, only 25 percent had been diagnosed with PTSD.

Researchers found strong evidence of overlapping genetic risk between PTSD and schizophrenia along with more modest evidence of overlap with bipolar and major depressive disorder.  They also found a stronger correlation with PTSD among women.

“All available evidence suggests that PTSD heritability among females is higher than males,” said the authors. “Female heritability is close to that of [schizophrenia] and [bipolar disorder], two of the most genetically influenced psychiatric disorders.”

The study found that three out of every 10 PTSD diagnoses among women exposed to trauma could be genetic. Women are known to be twice as likely as men to develop PTSD after a traumatic event, according to a CNN report.

It is possible that more women report cases of PTSD or men may be less reliable in their recollection of events and/or symptoms.

“Perhaps cultural factors that are more permissive for accurate reporting of PTSD symptoms in females contribute to more precise measurement of PTSD in females, and this would permit higher heritability estimates,” said the author, who hope to increase future studies to include over 75,000 participants for more accurate results.