Smaller hippocampal volume as a vulnerability factor for the persistence of post-traumatic stress disorder.
BACKGROUND
Smaller hippocampal volume has often been observed in patients with post-traumatic stress disorder (PTSD). However, there is no consensus whether this is a result of stress/trauma exposure, or constitutes a vulnerability factor for the development of PTSD. Second, it is unclear whether hippocampal volume normalizes with successful treatment of PTSD, or whether a smaller hippocampus is a risk factor for the persistence of PTSD.


METHODS
Magnetic resonance imaging (MRI) scans and clinical interviews were collected from 47 war veterans with PTSD, 25 healthy war veterans (combat controls) and 25 healthy non-military controls. All veterans were scanned a second time with a 6- to 8-month interval, during which PTSD patients received trauma-focused therapy. Based on post-treatment PTSD symptoms, patients were divided into a PTSD group who was in remission (n = 22) and a group in whom PTSD symptoms persisted (n = 22). MRI data were analysed with Freesurfer.


RESULTS
Smaller left hippocampal volume was observed in PTSD patients compared with both control groups. Hippocampal volume of the combat controls did not differ from healthy controls. Second, pre- and post-treatment analyses of the PTSD patients and combat controls revealed reduced (left) hippocampal volume only in the persistent patients at both time points. Importantly, hippocampal volume did not change with treatment.


CONCLUSIONS
Our findings suggest that a smaller (left) hippocampus is not the result of stress/trauma exposure. Furthermore, hippocampal volume does not increase with successful treatment. Instead, we demonstrate for the first time that a smaller (left) hippocampus constitutes a risk factor for the persistence of PTSD.
Department of Psychiatry,Brain Center Rudolf Magnus,University Medical Center Utrecht,Utrecht,The Netherlands.
S J H
SJ
van Rooij
Department of Psychiatry,Brain Center Rudolf Magnus,University Medical Center Utrecht,Utrecht,The Netherlands.
M
M
Kennis
Department of Psychiatry,Brain Center Rudolf Magnus,University Medical Center Utrecht,Utrecht,The Netherlands.
R
R
Sjouwerman
Department of Psychiatry,Brain Center Rudolf Magnus,University Medical Center Utrecht,Utrecht,The Netherlands.
M P
MP
van den Heuvel
Department of Psychiatry,Brain Center Rudolf Magnus,University Medical Center Utrecht,Utrecht,The Netherlands.
R S
RS
Kahn
Department of Psychiatry,Brain Center Rudolf Magnus,University Medical Center Utrecht,Utrecht,The Netherlands.
E
E
Geuze
D000328:Adult; D016022:Case-Control Studies; D006624:Hippocampus / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D011613:Psychotherapy / Q000379:methods*; D012307:Risk Factors; D013313:Stress Disorders, Post-Traumatic / Q000175:diagnosis* / Q000628:therapy*; D014728:Veterans / Q000523:psychology*
Hippocampal volume; magnetic resonance imaging; post-traumatic stress disorder; trauma-focused therapy; war veterans