White matter changes in paediatric bipolar disorder: A systematic review of diffusion magnetic resonance imaging studiesA systematic review of diffusion magnetic resonance imaging studies

Iman Kiani, Mohammad Hadi Aarabi, Giulia Cattarinussi, Fabio Sambataro, Virginia Favalli, Chiara Moltrasio, Giuseppe Delvecchio
Journal of Affective Disorders. 2025-03-01; 373: 67-79
DOI: 10.1016/j.jad.2024.12.042

1. J Affect Disord. 2025 Mar 15;373:67-79. doi: 10.1016/j.jad.2024.12.042. Epub
2024 Dec 15.

White matter changes in paediatric bipolar disorder: A systematic review of
diffusion magnetic resonance imaging studiesA systematic review of diffusion
magnetic resonance imaging studies.

Kiani I(1), Aarabi MH(2), Cattarinussi G(3), Sambataro F(4), Favalli V(5),
Moltrasio C(6), Delvecchio G(5).

Author information:
(1)Students’ Scientific Research Center (SSRC), Tehran University of Medical
Sciences, Tehran, Iran.
(2)Department of Neuroscience (DNS), Padua Neuroscience Center, University of
Padova, Padua, Italy; Padua Neuroscience Center, University of Padova, Padua,
Italy; Department of Radiology and Medical Imaging, University of Virginia,
Charlottesville, VA, USA.
(3)Department of Neuroscience (DNS), Padua Neuroscience Center, University of
Padova, Padua, Italy; Padua Neuroscience Center, University of Padova, Padua,
Italy; Department of Psychological Medicine, Institute of Psychiatry, Psychology
and Neuroscience, King’s College London, London, UK.
(4)Department of Neuroscience (DNS), Padua Neuroscience Center, University of
Padova, Padua, Italy; Padua Neuroscience Center, University of Padova, Padua,
Italy.
(5)Department of Neurosciences and Mental Health, Fondazione IRCCS Ca’ Granda
Ospedale Maggiore Policlinico, Milan, Italy.
(6)Department of Neurosciences and Mental Health, Fondazione IRCCS Ca’ Granda
Ospedale Maggiore Policlinico, Milan, Italy. Electronic address:
.

BACKGROUND: Paediatric bipolar disorder (PBD) is characterized by severe mood
fluctuations that deviate from typical childhood emotional development. Despite
the efforts, the pathophysiology of this disorder is not well understood yet. In
this review, we aimed to synthesize existing diffusion magnetic resonance
imaging (dMRI) research findings in PBD.
METHODS: A literature search was conducted using PubMed, Embase, Scopus, and Web
of Science databases to identify relevant studies published before April 2024.
RESULTS: A total of 23 studies were included in the review. The findings showed
variations of fractional anisotropy (FA), axial diffusivity, radial diffusivity,
and apparent diffusion coefficient in PBD compared to healthy controls (HCs).
Key findings included decreased FA in the anterior cingulate, anterior corona
radiata, and corpus callosum, particularly the genu, which correlated with
clinical symptoms. Furthermore, longitudinal studies emphasized the significance
of the uncinate fasciculus as having atypical developmental trajectories in PBD
compared to HCs. In addition, graph analysis revealed widespread changes in
structural connectivity, especially affecting the orbitofrontal cortex, frontal
gyrus, and basal ganglia. Lastly, machine learning models showed promising
results in differentiating PBD from HCs.
LIMITATIONS: Cross-sectional design of the studies, small sample sizes, and
different imaging protocols preclude integration of the findings.
CONCLUSION: PBD seems to be associated with widespread structural changes
compared to HC. Understanding these changes, which might account for the
clinical manifestations of this disorder, increase our knowledge of the
neurobiological underpinnings of PBD. This, in turn, may help develop more
effective treatments for this disorder.