Child abuse is a reliable predictor of post-traumatic stress disorder, but not all maltreated children suffer from it, according to Chad Shenk, assistant professor of human development and family studies, Penn State, who examined why some maltreated children develop PTSD and some do not.
Shenk and his research team found that adolescent girls who experienced maltreatment in the past year and were willing to talk about their painful experiences and their thoughts and emotions, were less likely to have PTSD symptoms one year later. Those who tried to avoid painful thoughts and emotions were significantly more likely to exhibit PTSD symptoms down the road. The researchers report their results in the current issue of Development and Psychopathology.
"Avoidance is something we all do," said Shenk. "Sometimes it is easier not to think about something. But when we rely on avoidance as a coping strategy... that is when there may be negative consequences."
Approximately 40 percent of maltreated children develop PTSD at some point in their lives. Shenk sought to identify the factors that kept the remaining 60 percent from experiencing the disorder.
"Children and adolescents react very differently to abuse, and we don't yet know who is going to develop PTSD and who won't," said Shenk. "What factors explain who will develop PTSD and who will not? This study attempted to identify those causal pathways to PTSD."
One theory holds that PTSD is caused by dysregulation in multiple neurobiological processes, including cortisol deficiencies or heightened suppression of respiratory sinus arrhythmia -- each of which affects how individuals can remain calm during a time of stress.
There are also psychological theories, which include experiential avoidance, the tendency to avoid negative feelings like fear, sadness or shame. Shenk's study tested these theories by creating one statistical model that included them all to see which factors best accounted for PTSD symptoms.
"It would be inappropriate to say that these are competing theories, but in the literature they are often treated that way," he said. "Investigators are actually focused on different levels of analysis, one neurological and one psychological, and I think these processes are related."
At three different points over two years, Shenk and his research team examined girls who suffered from at least one of the three types of child maltreatment -- physical abuse, sexual abuse or neglect -- during the previous year. The 51 maltreated adolescent girls were compared to 59 adolescent girls who had not experienced maltreatment.
Figuring out which processes conferred the greatest risk for PTSD could provide a basis for prevention and clinical intervention programs, Shenk said.
"If we can find what the cause or risk pathway is, then we know what to target clinically," he said.