A recent study has found that individuals with PTSD who have a larger hippocampus are more likely than other PTSD patients to benefit from exposure-based therapy, a common treatment method for the disorder.
The results of this study were published in the journal Psychiatry Research: Neuroimaging.
The research team was led by Mikael Rubin, M.A., former project coordinator at New York State Psychiatric Institute and current Ph.D. student at the University of Texas at Austin.
In this study, Rubin and colleagues looked at 50 participants with PTSD and 36 participants who had experienced trauma but did not develop PTSD. The researchers used magnetic resonance imaging, or MRI, to take “snapshots” of each participant’s brain and measure the volume of various brain regions. The hippocampus — a brain region engaged in memory processing — has been implicated in PTSD in the past, and so the researchers paid special attention to this region.
The researchers evaluated each participant at the start of the study and then after 10 weeks. Over the course of these 10 weeks, patients in the PTSD group received prolonged exposure therapy, a specific form of therapy designed to help individuals with PTSD cope with their trauma through breathing exercises, mental health education and exposure to safe events that trigger their symptoms.
When the researchers looked at each participant’s brain, they found that participants who experienced trauma but did NOT develop PTSD had a larger hippocampus than participants with PTSD.
They also found that participants with PTSD who responded positively to prolonged exposure therapy had a larger hippocampus than those who experienced no benefits from the treatment.
What does this mean?
From these results, it appears as though the hippocampus is at least in part protective against the symptoms of PTSD.
“If replicated, these findings have important implications for screening and treating patients who have been exposed to trauma,” explained Yuval Neria, Ph.D., professor of medical psychology at Columbia University Medical Center, director of the PTSD Program at New York State Psychiatric Institute and the senior author of the paper. “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.”
As mentioned previously, the hippocampus has been implicated in PTSD in the past. In 2006, researchers at Tufts University and Harvard Medical School systematically reviewed the scientific literature and found that, on average, individuals with PTSD had a smaller than average hippocampus as well as diminished neuronal and functional integrity in that region of the brain. In 2011, a study led by Brigitte A. Apfel, M.D., Ph.D., was published in the journal Biological Psychiatry that determined that PTSD patients with greater hippocampal volume were more likely to ultimately recover from the illness.
What makes this region so important? The researchers suspect that, along with memory consolidation, the hippocampus also plays a role in distinguishing the difference between safe and unsafe scenarios.
“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,” explained Rubin.
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About the author
Courtney Lopresti, M.S., is a senior staff writer for the Sovereign Health Group, where she uses her scientific background to write online blogs and articles for a general audience. At the University of Pittsburgh, where she earned her master’s in neuroscience, she used functional neuroimaging to study how the human cerebellum contributes to language processing. In her spare time, she writes fiction, reads Oliver Sacks and spends time with her two cats and bird. Courtney is currently located in Minneapolis. For more information and other inquiries about this article, contact the author at firstname.lastname@example.org.