Reduced posterior hippocampal volume in posttraumatic stress disorder.
OBJECTIVE
Hippocampal volume is reduced in posttraumatic stress disorder (PTSD). In the present study, we sought to determine whether volume loss is homogenously distributed or confined to a certain part of the structure.


METHODS
Twenty-two adult outpatients with PTSD (11 after prolonged prepubertal trauma and 11 after single adult trauma) and 22 matched healthy subjects were scanned at the National Institute of Mental Health using high-resolution 3T magnetic resonance imaging between September 2003 and August 2004. PTSD diagnosis was conferred using the Structured Clinical Interview for DSM-IV. Volumes of whole, anterior, and posterior hippocampus and subiculum were compared between groups.


RESULTS
Total hippocampal volume was lower in patients with PTSD (p = .02), with a significant diagnosis by hippocampal-subregion interaction (p = .02). Post hoc analysis revealed significantly smaller posterior hippocampi in PTSD (p = .006), with no difference in the volumes of anterior hippocampus or subiculum. No volume differences were found between PTSD participants with prolonged childhood abuse compared to single adult trauma exposure.


CONCLUSIONS
The posterior hippocampus has been associated with storage, processing, and retrieval of spatiotemporal memories, central to the protective function of fear conditioning. Volume deficit in the posterior hippocampus may indicate malfunction in this faculty, leading to the exaggerated conditioned fear response observed in PTSD.
Department of Psychiatry, Hadassah Hebrew University Medical Center, Jerusalem, Israel. bonne@hadassah.org.il
Omer
O
Bonne
Meena
M
Vythilingam
Masatoshi
M
Inagaki
Suzanne
S
Wood
Alexander
A
Neumeister
Allison C
AC
Nugent
Joseph
J
Snow
David A
DA
Luckenbaugh
Earle E
EE
Bain
Wayne C
WC
Drevets
Dennis S
DS
Charney
D000328:Adult; D001008:Anxiety Disorders / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology; D001931:Brain Mapping; D003865:Major Depressive Disorder / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D006624:Hippocampus / Q000033:anatomy & histology* / Q000503:physiopathology*; D006801:Humans; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging; D008297:Male; D012720:Severity of Illness Index; D013313:Stress Disorders, Post-Traumatic / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology; D013997:Time Factors