Study participants were divided into three groups: people who experienced trauma without developing PTSD, people with PTSD who were exposed to child abuse, and people with PTSD who were not exposed to child abuse.
The researchers were surprised to find that although hundreds of genes had significant changes in activity in the PTSD with and without child abuse groups, there was very little overlap in patterns between these groups. The two groups shared similar symptoms of PTSD, which include intrusive thoughts such as nightmares and flashbacks, avoidance of trauma reminders, and symptoms of hyperarousal and hypervigilance.
The PTSD with child abuse group displayed more changes in genes linked with development of the nervous system and regulation of the immune system, while the PTSD minus child abuse group displayed more changes in genes linked with apoptosis (cell death) and growth rate regulation. In addition, changes in methylation were more frequent in the PTSD with child abuse group. The authors believe that these biological pathways may lead to different mechanisms of PTSD symptom formation within the brain.
The Max Planck/Emory scientists were probing gene activity in blood cells, rather than brain tissue. Similar results have been obtained by researchers studying the influence of child abuse on the brains of people who had committed suicide.
"Traumatic events that happen in childhood are embedded in the cells for a long time," Binder says. "Not only the disease itself, but the individual's life experience is important in the biology of PTSD, and this should be reflected in the way we treat these disorders."
|Contact: Kathi Baker|
Emory Health Sciences