Cited by 65Schizophrenia research and treatmentAdvanced Neuroimaging Techniques and ApplicationsAdvanced MRI Techniques and Applications

White-matter free-water diffusion MRI in schizophrenia: A systematic review and meta-analysis

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Carreira Figueiredo, Inês, Borgan, Faith, Pasternak, Ofer, Turkheimer, Federico E., Howes, Oliver D.·2022·Neuropsychopharmacology

Abstract

White-matter abnormalities, including increases in extracellular free-water, are implicated in the pathophysiology of schizophrenia. Recent advances in diffusion magnetic resonance imaging (MRI) enable free-water levels to be indexed. However, the brain levels in patients with schizophrenia have not yet been systematically investigated. We aimed to meta-analyse white-matter free-water levels in patients with schizophrenia compared to healthy volunteers. We performed a literature search in EMBASE, MEDLINE, and PsycINFO databases. Diffusion MRI studies reporting free-water in patients with schizophrenia compared to healthy controls were included. We investigated the effect of demographic variables, illness duration, chlorpromazine equivalents of antipsychotic medication, type of scanner, and clinical symptoms severity on free-water measures. Ten studies, including five of first episode of psychosis have investigated free-water levels in schizophrenia, with significantly higher levels reported in whole-brain and specific brain regions (including corona radiata, internal capsule, superior and inferior longitudinal fasciculus, cingulum bundle, and corpus callosum). Six studies, including a total of 614 participants met the inclusion criteria for quantitative analysis. Whole-brain free-water levels were significantly higher in patients relative to healthy volunteers (Hedge’s g = 0.38, 95% confidence interval (CI) 0.07–0.69, p = 0.02). Sex moderated this effect, such that smaller effects were seen in samples with more females (z = −2.54, p < 0.05), but antipsychotic dose, illness duration and symptom severity did not. Patients with schizophrenia have increased free-water compared to healthy volunteers. Future studies are necessary to determine the pathological sources of increased free-water, and its relationship with illness duration and severity.

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  • Subsequent free-water meta-analysis supports an additional extracellular-water component, but the biological basis of altered diffusion remains heterogeneous and may reflect different contributions from axons, myelin, extracellular water, inflammation, medication exposure, and illness course.

    “Subsequent free-water meta-analysis supports an additional extracellular-water component, but the biological basis of altered diffusion remains heterogeneous and may reflect different contributions from axons, myelin, extracellular water, inflammation, medication exposure, and illness course (Carreira Figueiredo et al., 2022).”

    From 40 Years of diffusion MRI in the brain: From history to emerging frontiers (2026) · cites this paper as Carreira Figueiredo et al., 2022

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Authors
Carreira Figueiredo, I., Borgan, F., Pasternak, O., Turkheimer, F. E., & Howes, O. D.
Affiliations
  • King's College London (GB)
  • Brigham and Women's Hospital (US)
  • Lundbeck (Denmark) (DK)
Venue
Neuropsychopharmacology
Published
2022-01-15
Volume
47
Issue
7
Pages
1413-1420
ISSN
  • 0893-133X (ISSN-L)
  • 1740-634X
OpenAlex
W4206636852
Cited by
65
References
60
Citations by year
2026: 14 · 2025: 17 · 2024: 18 · 2023: 13 · 2022: 3
FWCI
2.19
Type
journal article
Language
en
Open access
Locations
  • Neuropsychopharmacology (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
Funders
  • RCUK | Medical Research Council
  • Wellcome Trust
Topics
  • Health Sciences › Medicine › Psychiatry and Mental health › Schizophrenia research and treatment
  • Health Sciences › Medicine › Radiology, Nuclear Medicine and Imaging › Advanced Neuroimaging Techniques and Applications
  • Health Sciences › Medicine › Radiology, Nuclear Medicine and Imaging › Advanced MRI Techniques and Applications
Keywords
schizophrenia, white matter, extracellular free water, diffusion MRI, first-episode psychosis, sex differences, corpus callosum, corona radiata, internal capsule, longitudinal fasciculus, cingulum, disease duration, antipsychotic dosing, symptom severity
MeSH terms
Brain, Female, Humans, Schizophrenia, Antipsychotic Agents, Water, Anisotropy, Diffusion Magnetic Resonance Imaging, White Matter

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