Women have a Greater Genetic Risk for PTSD

Women have a higher genetic risk for post-traumatic stress disorder (PTSD) than men, finds new research published recently in the American Journal of Psychiatry. In fact, women are more than twice as likely as men to develop PTSD, researchers found. The study, researchers said, demonstrated for the first time that woman have a greater inherited biological risk for PTSD.

About 6 six out of every 100 people will experience PTSD at some point in their lives. PTSD is a psychiatric disorder that can occur in people who have experienced or witnessed a traumatic event. PTDS is more common in women than men, and it is known to have both genetic and environment influence.

“Some of the theories as to why PTSD is more prevalent in women have frankly been unkind, such as attributing the sex difference to a weakness or lack of ability to cope,” said Ananda B. Amstadter, Ph.D., lead investigator and a professor in the VCU School of Medicine’s departments of Psychiatry and Human and Molecular Genetics and lead author of the study.

Amstadter and her colleagues at the VCU School of Medicine collaborated with researchers at Lund University in Sweden. They used the Swedish National Registries to search for patients with PTSD to the model the genetic and environmental variance and to test for quantitative and qualitative sex differences in twins and sibling pairs. In Sweden, anonymized clinical data for the entire population of Sweden is included in national registries, which are used for research and to help improve healthcare in the country.

In this analysis, Amstadter and her colleagues, identified more than 16,000 twin pairs and 376,000 sibling pairs, making this the largest study to examine genetic and environmental influences on PTSD.

They found that the heritability of PTSD was 7 percentage points higher in women than men (35.4% compared with 28.6%). This suggests, researchers said, that genetics plays a bigger role in women than men. Most the genes involved in PTSD are shared by both men and women, but some genes are specific to women. Researchers said they now working with the Psychiatric Genomics Consortium to identify all the molecular genetic variants that account for the difference in men and women.

The study has some limitations, researchers said. They were unable to determine the difference between the efforts of trauma exposure and PTSD. Sex differences in trauma type exposure are an important consideration, researchers said. Additionally, researchers said the main source of data was from primary care data rather than data from psychologies or psychiatrists.