Introduction: Alterations in cerebral blood flow (CBF) in subjects with
psychosis spectrum disorders (PSD) and clinical high-risk (CHR) states
may provide insights into the pathophysiology of these disorders. Arterial
spin labeling (ASL) facilitated a more comprehensive examination of CBF
in these subjects. This meta-analysis synthesizes findings on CBF in PSDs
and CHR states, addressing literature gaps.
Methods: A systematic literature search of the PubMed database was
performed using a protocol based on the PRISMA statement and the
recommendations of the MOOSE group. Studies eligible for inclusion
in the review involved: I) individuals with PSD, first-episode psychosis
or CHR state, II) had healthy controls for comparison, III) neuroimaging
should be performed with MRI using the pseudo-continuous ASL
method, IV) resting cerebral blood flow (rCBF) should be recorded.
Information related to participants, CBF analyses, and results were
systematically extracted.
Results: The PubMed search for the meta-analysis identified 69
publications, including 24 articles that met the inclusion criteria for the
meta-analysis, representing 491 SSD patients, 185 CHR states, and 554
controls. Studies included rCBFs for the whole brain, gray matter, and
striatum. The meta-analysis results indicated that patients with PSD had
decreased gray matter rCBF compared to controls (Hedge’s g=0.33, 95%
CI [0.08, 0.57]), but no difference in the whole brain (Hedge’s g=0.09,
95% CI [-0.70, 0.88] and striatum rCBF (Hedge’s g=0.38, 95% CI [-0.23,
1.00]). Additionally, subjects with CHR state showed no differences in the
striatum rCBF compared to the controls (Hedge’s g=-0.15, 95% CI [-0.80,
0.51]).
Conclusions: This suggests that although perfusion changes in gray
matter are present in PSD, they may not extend to wider brain regions
or specific structures such as the striatum. Furthermore, the results
imply that rCBF may be differentially regulated in subjects with PSD
and CHR. Updated findings highlight hemodynamic correlations in PSD
pathophysiology.
Keywords: Arterial spin labeling, neuroimaging, perfusion, psychotic
disorders, schizophrenia