UM Researchers Identify Genetic Link to Post-Traumatic Stress Disorder
Exposure to severe trauma is extraordinarily common in the United States and worldwide, and in turn, post-traumatic stress disorder (PTSD) is now one of the most common of the major psychiatric disorders. Identifying who is at risk for developing PTSD after a traumatic event, such as rape, combat, or natural disaster, is essential to determining appropriate treatment. A University of Miami Miller School of Medicine researcher and her collaborators published findings on February 23 in the prestigious journal Nature about a new gene linked to PTSD.
“When someone goes through a trauma it is hard to know who to treat because not everyone exposed to trauma develops PTSD,” says Amanda Myers, Ph.D., assistant professor of psychiatry and behavioral sciences at the Miller School and co-author of the study. “Treating individuals who do not develop PTSD after trauma can actually be harmful; therefore it is crucial to discover biomarkers for who will develop PTSD as well as mapping pathways involved in PTSD to help develop better therapies. Our new finding is one step in helping us figure out the biological markers and pathways involved in understanding who is at risk for developing PTSD.”
The scientists used blood samples taken from more than 1,200 highly traumatized patients treated in an Atlanta emergency room, some of whom went on to develop PTSD and others who did not. Dr. Myers and her colleagues at the Department of Psychiatry and Behavioral Sciences at Emory University School of Medicine in Atlanta were able to use the samples to map an effect in the pituitary adenylate cyclase activating polypeptide (PACAP) gene and its receptor PAC 1.
PACAP, the protein produced by the gene, is known to broadly regulate the cellular stress response, and was found to be over-expressed in individuals with PTSD. Through a combination of expression analysis and modeling of behavior in both mice and humans, Dr. Myers and her colleagues have shown a female-specific association with particular genetic variants in the PAC 1 receptor which causes the changes in gene expression and behavior.
“This is important work because at the current time there is no reliable set of predictors that can inform clinicians as to who will or will not develop PTSD after trauma exposure,” says Charles Nemeroff, M.D., Ph.D., Miller Professor and Chairman of the Department of Psychiatry and Behavioral Sciences at the Miller School. He was involved, while a faculty member at Emory, with the grant that started the blood sample collection in Atlanta. “There is increasing evidence, largely from the World Trade Center attacks, that immediate psychological intervention for all trauma victims is not only ineffective, but may actually interfere with normal recovery.”
Even among those who undergo appropriate treatment, 25 to 40 percent develop syndromal or long-standing PTSD. Developing biological markers as Dr. Myers and her colleagues have done will play a role in identifying and further defining the intervention process to help aid those who will eventually develop PTSD.