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Bilateral hippocampal volume reduction in adults with post-traumatic stress disorder: a meta-analysis of structural MRI studies
Smith ME.. Hippocampus, 2005-01-01
Topic: Brain proteins, microglia and lab models
Over the last decade a significant number of studies have reported smaller hippocampal volume in individuals with symptoms of post-traumatic stress disorder (PTSD) relative to control groups, and in some cases hemispheric asymmetries in this effect have been noted. However these reported asymmetries have not been in a consistent direction, and other well-controlled studies have failed to observe any hippocampal volume difference. This paper reports a systematic review and meta-analysis of studies in which hippocampal volume was estimated from magnetic resonance images in adult patients with PTSD. After applying a variety of selection criteria intended to minimize potential confounds in pooled effect-size estimates, the meta-analysis included 13 studies of adult patients with PTSD that compared the patients to well-matched control groups, for a total of 215 patients and 325 control subjects. The studies varied with respect to participant age, gender distribution, source of trauma, severity of symptoms, duration of disorder, the nature of the control groups, and the methods employed for volumetric quantification. Despite these differences, pooled effect size calculations across the studies indicated significant volume differences in both hemispheres. On average PTSD patients had a 6.9% smaller left hippocampal volume and a 6.6% smaller right hippocampal volume compared with control subjects. These volume differences were smaller when comparing PTSD patients with control subjects exposed to similar levels of trauma, and larger when comparing PTSD patients to control subjects without significant trauma exposure. Such differences are consistent with the notion that exposure to stressful experiences can lead to hippocampal atrophy, although prospective studies would be necessary to unambiguously establish such a relationship.
Cite this study APA, Vancouver, BibTeX · download .bib or .ris
APA 7th
Smith, M. E. (2005). Bilateral hippocampal volume reduction in adults with post-traumatic stress disorder: a meta-analysis of structural MRI studies. Hippocampus. https://doi.org/10.1002/hipo.20102
Vancouver
Smith ME. Bilateral hippocampal volume reduction in adults with post-traumatic stress disorder: a meta-analysis of structural MRI studies. Hippocampus. 2005. doi:10.1002/hipo.20102. PMID: 15988763.
BibTeX
@article{smith2005-15988763,
author = {Smith, M. E.},
title = {{Bilateral hippocampal volume reduction in adults with post-traumatic stress disorder: a meta-analysis of structural MRI studies}},
journal = {Hippocampus},
year = {2005},
doi = {10.1002/hipo.20102},
pmid = {15988763},
url = {https://doi.org/10.1002/hipo.20102}
}
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Key findings
- Over the last decade a significant number of studies have reported smaller hippocampal volume in individuals with symptoms of post-traumatic stress disorder (PTSD) relative to control groups, and in some cases hemispheric asymmetries in this effect have been noted.
- Despite these differences, pooled effect size calculations across the studies indicated significant volume differences in both hemispheres.
- On average PTSD patients had a 6.9% smaller left hippocampal volume and a 6.6% smaller right hippocampal volume compared with control subjects.
- These volume differences were smaller when comparing PTSD patients with control subjects exposed to similar levels of trauma, and larger when comparing PTSD patients to control subjects without significant trauma exposure.
Study details
- Study designsystematic review
- Participants13
- Effect size6.9%; 6.6%
- Evidence strengthHigh
How this study scored 74/100
Published in a peer-reviewed journal, and it is a systematic review of all the studies on the question. We have no data on journal's citation record, times cited, citations per year, impact for its field and year, cited by studies here, still being cited, senior author's track record, institution's track record and multi-centre collaboration, so those were left out: it earned 43 of the 58 points we could judge it on, which is 74 out of 100.
| Component | Points | Why |
|---|---|---|
| Journal tier | 7 / 10 | Tier 3 — peer-reviewed journal (Hippocampus) |
| Journal's citation record | — / 4 | No journal record from OpenAlex — left out of this score |
| Study design | 12 / 12 | A systematic review of all the studies on the question |
| Strength of evidence | 5 / 5 | Rated “high” in our summary |
| Peer-review validation | 10 / 10 | Peer-reviewed. Published as an article in a named peer-reviewed journal. |
| How recent | 1 / 5 | 2005 — older than 20 years, still counted |
| Sample size | 1 / 4 | 13 participants |
| Effect reported | 2 / 3 | Effect reported as a number, without an interval or test |
| Studied in people | 3 / 3 | Studied in people (participant count stated) |
| Randomised / blinded | 0 / 2 | A review of other studies — randomisation is not credited here |
| Times cited | — / 7 | No citation count (not found in OpenAlex) — left out of this score |
| Citations per year | — / 5 | No citation count or no year — left out of this score |
| Impact for its field and year | — / 6 | No field-weighted citation impact (OpenAlex has none yet) — left out of this score |
| Cited by studies here | — / 6 | Not yet checked against this library's citation graph — left out of this score |
| Still being cited | — / 4 | No yearly citation counts — left out of this score |
| Senior author's track record | — / 4 | Senior author's record not available — left out of this score |
| Institution's track record | — / 3 | No institution listed in OpenAlex — left out of this score |
| Multi-centre collaboration | — / 3 | Institutions not listed — left out of this score |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 15988763) |
| Free to read | 0 / 2 | Behind a paywall — scores zero |
| Points | 43 / 58 | Scored on 11 of 20 parts. We have no data for the rest, so they are left out: 43 of the 58 points we could judge it on is 74 out of 100. |
| Total | 74 / 100 | — |
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