Royal College of Surgeons in Ireland
MRI volumetric changes in hippocampal subfields in psychosis....pdf (929.48 kB)

MRI volumetric changes in hippocampal subfields in psychosis: a protocol for a systematic review and meta-analysis

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journal contribution
posted on 2022-05-18, 16:44 authored by Anurag Nasa, Olivia Mosley, Elena Roman, Allison Kelliher, Caoimhe Gaughan, Kirk J Levins, David Coppinger, Erik O’Hanlon, Mary CannonMary Cannon, Darren W Roddy

Background: The hippocampus has for long been known for its ability to form new, declarative memory. However, emerging findings across conditions in the psychosis spectrum also implicate its role in emotional regulation. Systematic reviews have demonstrated consistent volume atrophic changes in the hippocampus. The aim of the systematic review and metanalysis which will follow from this protocol will be to investigate the volume-based neuroimaging findings across each of the subfields of the hippocampus in psychosis independent of diagnosis.

Methods: Volume changes across subfields of the hippocampus in psychotic illnesses will be assessed by systematic review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). MRI neuroimaging studies of patients with a definitive diagnosis of psychosis (including brief pre-diagnostic states) will be included. Studies lacking adequate controls, illicit drug use, medical psychosis, history of other significant psychiatric comorbidities, or emphasis on age groups above 65 or below 16 will be excluded. Subfields investigated will include the CA1, CA2/3, CA4, subiculum, presubiculum, parasubiculum, dentate gyrus, stratum, molecular layer, granular cell layer, entorhinal cortex, and fimbria. Two people will independently screen abstracts from the output of the search to select suitable studies. This will be followed by the two reviewers performing a full-text review of the studies which were selected based on suitable abstracts. One reviewer will independently perform all the data extraction, and another reviewer will then systemically check all the extracted information using the original articles to ensure accuracy. Statistical analysis will be performed using the metafor and meta-packages in R Studio with the application of the random-effects model.

Discussion: This study will provide insight into the volumetric changes in psychosis of the subfields of the hippocampus, independent of diagnosis. This may shed light on the intricate neural pathology which encompasses psychosis and will open avenues for further exploration of the structures identified as potential drivers of volume change.

Systematic review registration: PROSPERO CRD42020199558.


ERC as part of the iHEAR project



The original article is available at

Published Citation

Nasa A. et al. MRI volumetric changes in hippocampal subfields in psychosis: a protocol for a systematic review and meta-analysis. Syst Rev. 2022;11(1):44

Publication Date

15 March 2022

PubMed ID



  • Beaumont Hospital
  • Psychiatry

Research Area

  • Neurological and Psychiatric Disorders


BioMed Central


  • Published Version (Version of Record)