TY - JOUR
T1 - Clarifying the origin of biological abnormalities in PTSD through the study of identical twins discordant for combat exposure
AU - Pitman, Roger K.
AU - Gilbertson, Mark W.
AU - Gurvits, Tamara V.
AU - May, Flavia S.
AU - Lasko, Natasha B.
AU - Metzger, Linda J.
AU - Shenton, Martha E.
AU - Yehuda, Rachel
AU - Orr, Scott P.
PY - 2006/7
Y1 - 2006/7
N2 - A biological abnormality found to be associated with post-traumatic stress disorder (PTSD) may be, among other things, a pretrauma vulnerability factor, that is, it may have been present prior to the event's occurrence and increased the individual's likelihood of developing PTSD upon traumatic exposure. Alternately, it may be an acquired PTSD sign, that is, it may have developed after the traumatic exposure, along with the PTSD. We have studied pairs of Vietnam combat veterans and their noncombat-exposed, identical twins in an effort to resolve these competing origins. Combat veterans were diagnosed as current PTSD or non-PTSD (i.e., never had). Average heart rate responses (HRRs) to a series of sudden, loud-tone presentations were larger in Vietnam combat veteran twins with PTSD, but these larger responses were not shared by their noncombat-exposed cotwins, whose responses were similar to those of the non-PTSD combat veterans and their noncombat-exposed cotwins. These results suggest that larger HRRs to sudden, loud tones represent an acquired sign of PTSD. In contrast, increased neurological soft signs (NSSs), diminished hippocampal volume, and presence of abnormal cavum septum pellucidum (CSP) were found in Vietnam combat veteran twins with PTSD and their "high-risk," unexposed cotwins compared to Vietnam combat veteran twins without PTSD and their "low-risk," unexposed cotwins. These results support the conclusion that the latter abnormalities represent antecedent, familial vulnerability factors for developing chronic PTSD upon exposure to a traumatic event.
AB - A biological abnormality found to be associated with post-traumatic stress disorder (PTSD) may be, among other things, a pretrauma vulnerability factor, that is, it may have been present prior to the event's occurrence and increased the individual's likelihood of developing PTSD upon traumatic exposure. Alternately, it may be an acquired PTSD sign, that is, it may have developed after the traumatic exposure, along with the PTSD. We have studied pairs of Vietnam combat veterans and their noncombat-exposed, identical twins in an effort to resolve these competing origins. Combat veterans were diagnosed as current PTSD or non-PTSD (i.e., never had). Average heart rate responses (HRRs) to a series of sudden, loud-tone presentations were larger in Vietnam combat veteran twins with PTSD, but these larger responses were not shared by their noncombat-exposed cotwins, whose responses were similar to those of the non-PTSD combat veterans and their noncombat-exposed cotwins. These results suggest that larger HRRs to sudden, loud tones represent an acquired sign of PTSD. In contrast, increased neurological soft signs (NSSs), diminished hippocampal volume, and presence of abnormal cavum septum pellucidum (CSP) were found in Vietnam combat veteran twins with PTSD and their "high-risk," unexposed cotwins compared to Vietnam combat veteran twins without PTSD and their "low-risk," unexposed cotwins. These results support the conclusion that the latter abnormalities represent antecedent, familial vulnerability factors for developing chronic PTSD upon exposure to a traumatic event.
KW - Hippocampus
KW - Magnetic resonance imaging
KW - Monozygotic
KW - Neurological examination
KW - Posttraumatic
KW - Septum pellucidum
KW - Startle response
KW - Stress disorders
KW - Twins
UR - http://www.scopus.com/inward/record.url?scp=33746441924&partnerID=8YFLogxK
U2 - 10.1196/annals.1364.019
DO - 10.1196/annals.1364.019
M3 - Article
C2 - 16891575
AN - SCOPUS:33746441924
SN - 0077-8923
VL - 1071
SP - 242
EP - 254
JO - Annals of the New York Academy of Sciences
JF - Annals of the New York Academy of Sciences
ER -