Nature Neuroscience5, 1242 - 1247 (2002)
Published online: 15 October 2002; | doi:10.1038/nn958
Smaller hippocampal volume predicts pathologic vulnerability to psychological trauma
Mark W. Gilbertson1, 2, Martha E. Shenton2, 3, 4, Aleksandra Ciszewski4, Kiyoto Kasai4, Natasha B. Lasko1, 2, 5, Scott P. Orr1, 2, 5
& Roger K. Pitman2, 5
1
Research Service, Veterans Administration Medical Center, 718 Smyth Road, Manchester, New Hampshire 03104, USA
2
Department of Psychiatry, Harvard Medical School, Boston, Massachusetts 02115, USA
3
Psychiatry Service, Veterans Administration Boston Healthcare System, Brockton, Massachusetts 02301, USA
4
Department of Radiology, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA
5
Department of Psychiatry, Massachusetts General Hospital, Boston, Massachusetts 02129, USA
In animals, exposure to severe stress can damage the hippocampus. Recent human studies show smaller hippocampal volume in individuals with the stress-related psychiatric condition posttraumatic stress disorder (PTSD). Does this represent the neurotoxic effect of trauma, or is smaller hippocampal volume a pre-existing condition that renders the brain more vulnerable to the development of pathological stress responses? In monozygotic twins discordant for trauma exposure, we found evidence that smaller hippocampi indeed constitute a risk factor for the development of stress-related psychopathology. Disorder severity in PTSD patients who were exposed to trauma was negatively correlated with the hippocampal volume of both the patients and the patients' trauma-unexposed identical co-twin. Furthermore, severe PTSD twin pairs—both the trauma-exposed and unexposed members—had significantly smaller hippocampi than non-PTSD pairs.
