Researchers from Emory University and the University of Vermont have discovered that women who suffer from post-traumatic stress disorder (PTSD) have high blood levels of a stress-related hormone known as pituitary adenylate cyclase-activating polypeptide (PACAP). The new study was recently published online journal Nature.
PTSD is a severe anxiety disorder that develops after exposure to a terrifying event, such as a violent personal assault, natural or human-caused disaster, military combat, or an accident, that results in psychological trauma. The victim often re-experiences the event through flashbacks or nightmares, and may avoid stimuli associated with the trauma, or become overly vigilant to the point of paranoia.
Because PCAP is known to affect several functions of the body including metabolism, blood pressure, pain sensitivity, immune function, and the activity of the central nervous system, the identification of the hormone as an indicator of PTSD could pave the way for new methods in the diagnosis and treatment of anxiety disorders. According to lead study author Dr. Kerry Ressler, “Few biological markers have been available for PTSD or for psychiatric diseases in general. These results give us a new window into the biology of PTSD.”
For their study, the researchers assessed a group of 64 highly traumatized people who were treated at Grady Memorial Hospital in Atlanta, Georgia, among whom several had developed PTSD. Upon measuring the PACAP blood levels of the participants, the research team discovered that the PACAP levels were higher in those suffering from PTSD, and that elevated levels of the hormone correlated with the severity of symptoms. However, the increased amounts of PACAP were found to be significant only among women in the study.
Regarding the findings, Kessler acknowledged, “When we started we didn’t have any expectation that there was going to have a gender specificity to it.” He went on to explain, “We were just looking and found a smaller effect, and then we split it by gender and found that the whole effect was in females.”
Based on their initial findings, researchers performed another assessment on a group of 74 traumatized women. Once again, the results showed that elevated PACAP levels correlated with PTSD symptoms including flashbacks, avoidance of trauma reminders and increased startle response. In their report, the researchers concluded, “These data may begin to explain sex-specific differences in PTSD diagnosis, symptoms and fear physiology.”