UAlbany Study: PTSD Can Develop Even Without Memory of the Trauma
Andrew Poulos is the principal investigator on the study. (Photo by Mark Schmidt)
PHILADELPHIA, PA. (August 14, 2014) – There are many forms of memory and only some of these may be critical for the development of posttraumatic stress disorder (PTSD), according to a new study by University at Albany psychology professor Andrew M. Poulos and colleagues, as well as researchers at the University of California, Los Angeles.
Their findings, published in the current issue of Biological Psychiatry, suggest that even with no explicit memory of an early childhood trauma, symptoms of PTSD can still develop in adulthood. There are case reports of people who have experienced terrible life events that resulted in brain damage, some of whom developed syndromes similar to PTSD even though they had no recollection of the event itself.
Poulos is the principal investigator on a study examining whether people can still develop PTSD through fear conditioning even if they have no explicit recollection of the trauma itself.
In the laboratory, the researchers exposed juvenile rodents to a single session of unpredictable stress. When the rodents became adults, the researchers tested the animals for their memory of the event and also measured their fear response.
“We found that our rodents, which failed to remember the environment in which they were traumatized, showed a persistent increase in anxiety related behavior and increased learning of new fear situations. These heightened levels of fear and anxiety corresponded with drastic changes in the daily rhythms of the circulating hormone corticosterone,” said Poulos.
Corticosterone is a hormone that, in part, regulates the body’s stress response. Within the amygdala, a brain region crucial for the learning of fear, levels of a receptor for corticosterone were also increased.
Poulos added, “Future experiments in our laboratory will allow us to determine if this increase in glucocorticoid receptors within the amygdala and/or aberrant hormone levels sets up the organism for increased fear and anxiety.”
Taken together, these findings indicate that not remembering a traumatic event does not preclude an organism from experiencing some of the negative consequences of trauma, such as anxiety and heightened fear.
“These data highlight the importance of the many ways in which the brain processes traumatic experiences. Psychotherapy tends to focus heavily on the articulation of trauma memories. However, the current study highlights that these explicit memories may not represent all brain processes that drive distress and disability,” said John Krystal, editor of Biological Psychiatry. He is also chair of the Department of Psychiatry at the Yale University School of Medicine, Chief of Psychiatry at Yale-New Haven Hospital, and a research psychiatrist at the VA Connecticut Healthcare System.
“In other words there may be a mismatch between what people think and how they feel about their traumatic experiences. Thus, there may be a role in treatment for measuring other dimensions of response, such as physiological arousal, through which some of these other forms of learning are expressed,” added Krystal.
The article is Amnesia for Early Life Stress Does Not Preclude the Adult Development of Posttraumatic Stress Disorder Symptoms in Rats by Andrew M. Poulos, Maxine Reger, Nahili Mehta, Irina Zhuravka, Sarah S. Sterlace, Camille Gannam, David A. Hovda, Christopher C. Giza, and Michael S. Fanselow. The article appears in Biological Psychiatry, Vol. 76, Issue 4 (August 15, 2014), published by Elsevier.