Royal College of Surgeons in Ireland
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Reduced hippocampal volume in adolescents with psychotic experiences: a longitudinal population-based study

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posted on 2022-04-20, 16:33 authored by Ana Calvo, Darren W Roddy, Helen CoughlanHelen Coughlan, Ian KelleherIan Kelleher, Colm Healy, Michelle Harley, Mary ClarkeMary Clarke, Alexander Leemans, Thomas Frodl, Erik O'Hanlon, Mary CannonMary Cannon

Aims: Smaller hippocampal volumes are among the most consistently reported neuroimaging findings in schizophrenia. However, little is known about hippocampal volumes in people who report psychotic experiences. This study investigated differences in hippocampal volume between young people without formal diagnoses who report psychotic experiences (PEs) and those who do not report such experiences. This study also investigated if any differences persisted over two years.

Methods: A nested case-control study of 25 adolescents (mean age 13.5 years) with reported PEs and 25 matched controls (mean age 13.36 years) without PEs were drawn from a sample of 100 local schoolchildren. High-resolution T1-weighted anatomical imaging and subsequent automated cortical segmentation (Freesurfer 6.0) was undertaken to determine total hippocampal volumes. Comprehensive semi-structured clinical interviews were also performed including information on PEs, mental diagnoses and early life stress (bullying). Participants were invited for a second scan at two years.

Results: 19 adolescents with PEs and 19 controls completed both scans. Hippocampal volumes were bilaterally lower in the PE group compared to the controls with moderate effects sizes both at baseline [left hippocampus p = 0.024 d = 0.736, right hippocampus p = 0.018, d = 0.738] and at 2 year follow up [left hippocampus p = 0.027 d = 0.702, right = 0.048 d = 0.659] throughout. These differences survived adjustment for co-morbid mental disorders and early life stress.

Conclusions: Psychotic experiences are associated with total hippocampal volume loss in young people and this volume loss appears to be independent of possible confounders such as co-morbid disorders and early life stress.


European Research Council Consolidator Award [724809 iHEAR]

Health Research Board Ireland [HRA/PHS/2-012/28]

Alicia Koplowitz grant for ShortTerm Placements from the Alicia Koplowitz Foundation

Interdisciplinary Capacity Enhancement Award from the Health Research Board (ICE/2012/11)

VIDI Grant 639.072.411 from the Netherlands Organization for Scientific Research (NWO)

STaR lectureship from the Royal College of Surgeons in Ireland



The original article is available at

Published Citation

Calvo A. et al. Reduced hippocampal volume in adolescents with psychotic experiences: a longitudinal population-based study. PLoS One. 2020;15(6):e0233670

Publication Date

3 June 2020

PubMed ID



  • Beaumont Hospital
  • Psychiatry


Public Library of Science


  • Published Version (Version of Record)