NEW YORK, May 13 (UPI) -- While a smaller hippocampus has been linked to higher risk for post-traumatic stress disorder, a larger hippocampus was shown in a recent study to increase the likelihood that treatment will have a positive effect.
The size of a person's hippocampus, the part of the brain responsible for differentiating between safety and danger, is directly related to PTSD and its treatment, researchers at Columbia University report in the study, published in the journal Psychiatry Research: Neuroimaging.
The study, researchers say, continues to strengthen theories that the hippocampus plays a large role in PTSD, including that size can indicate both intensity of the condition and how effectively it can be treated.
"If replicated, these findings have important implications for screening and treating patients who have been exposed to trauma," Dr. Yuval Neria, a professor of medical psychology at Columbia University Medical Center and director of the PTSD Program at the New York State Psychiatric Institute, said in a press release. "For example, new recruits for military service may be scanned before an assignment to determine whether they are capable of dealing with the expected stress and trauma. Having a smaller hippocampus may be a contraindication for prolonged exposure to trauma."
For the study, researchers recruited 76 people -- 40 with PTSD and 36 trauma-exposed but healthy, resilient people -- to undergo clinical assessments and MRI, and then go through 10 weeks of prolonged exposure treatment.
Among the participants, the healthy people and 23 PTSD patients who responded to treatment had larger hippocampal volume at the start of the study than the 17 PTSD patients who did not respond to PE treatment.
While the researchers say the study supports ideas that hippocampal size is important both to the development of PTSD and response to treatment, more research is needed to confirm the connection and find more effective treatment.
"While we only studied response to prolonged exposure therapy, future research may help to determine if PTSD patients with a smaller hippocampus respond better to other treatments such as medication, either alone or in combination with psychotherapy," said Mikael Rubin, a doctoral student at the University of Texas at Austin.