Table 2.

White matter neuroimaging studies in CHR and psychosis conversion.

Author/year	Modality	Study Type	Age range (mean)	Case n	Country, Other	Abnormalities
Waszczuk et al., 2022 [64]	Diffusion	SS	25.1	12	Poland	no group difference in CHR
Smigielski et al., 2022 [65]	Diffusion	SS	20.9	37	Switzerland	↓FA in splenium of CC ↓FA in CC, corona radiata, motor/sensory tracts with conv.
Waszczuk et al., 2021 [66]	Diffusion	SR	na	881	na	subtle changes usually esp. in SLF, ILF, IFOF
Nagele et al., 2021 [67]	Diffusion	SS	21.3	30	Germany	no CHR group difference Widespread ↓FA prior to conv
Merritt et al., 2021 [42]	Diffusion	SR	na	2473a	na	No normal longitudinal volume and FA increase Decreasing volume and FA w conv.
Kristensen et al., 2021 [68]	Diffusion	SS	24	110	Denmark	Global FA predicted conversion
Fitzsimmons et al. 2020 [61]	Diffusion	SS	21.1	20	US	Cingulum ↓FA↑RD↑trace in CHR
Tomyshev et al. 2019 [33]	Diffusion	SS	20.4	30	Russia males only	↑RD in L ATR
Krakauer et al. 2018 [69]	Diffusion	SS	24.1	30	Denmark	↑FA in L SLF after 12 months
Krakauer et al. 2017 [60]	Diffusion	SS	23.7	45	Denmark	Widespread ↓FA↑RD↓AD in CHR
Rigucci et al., 2016 [70]	Diffusion	SS	21.3	27	Italy	↓FA in CC, L SLF, L ILF, forceps ↑RD in CC, ATR, cingulum
Bakker et al., 2016 [71]	Diffusion	SS	24.3	23	Netherlands	no FA group difference ↑MD, RD in CC, ATR, cortical fasciculi in CHR
Vijayakumar et al., 2016 [72]	Diffusion	SR	na	na	na	↓fronto-temporal and fronto-limbic connections, including SLF, uncinate fasc, cingulum and CC
Katagiri et al. 2015 [73]	Diffusion	SS	na	41	Japan	↓FA in region of CC in CHR
Klauser et al. 2015 [26]	Structural (white)	SS	21.5	69	Singapore	none
Schmidt et al., 2015 [74]	Diffusion	SS	25.4	28	Switzerland	↑FA in SLF, uncinate, R ATR
Von Hohenberg et al. 2014 [63]	Diffusion	SS	20.6	28	US	↑MD in regions of R SLF, corona radiata, CC in CHR
Ziermans et al. 2012 [51]	Structural (white)	SS	15.6	43	Netherlands	↓cerebal wm increase ↓cerebal wm increase with conv.
Carletti et al. 2012 [75]	Diffusion	SS	23.4	32	England	Widespread ↓FA in CHR Widespread ↓FA with conv
Bloemen et al. 2010 [76]	Diffusion	SS	18.9	37	Netherlands	↓FA in R putamen and L SLF with conv. ↑FA in L MTL with conv.
Peters et al. 2010 [77]	Diffusion	SS	21.2	17	Netherelands male only	no baseline group differences
Karlsgodt et al. 2009 [62]	Diffusion	SS	17	36	US	SLF ↓FA in CHR ↓FA in MTL and ILF predicted social dysfunction
Witthaus et al. 2008 [59]	Structural (white)	SS	25.1	30	Germany	↓L sup temp lobe
Walterfang et al. 2008 [78]	Structural (white)		20.2	100	Australia AN	no CC abnormality in CHR ↓ant genu of CC with conv.

AN = antipsychotic naïve; ATR = anterior thalamic radiation; BG = basal ganglia; CC = corpus callosum; CHR = clinical high risk (for psychosis); conv = conversion to psychosis; DLPFC = dorsolateral prefrontal cortex; IFOF = inferior front-occipital fasciculus; IPL = inferior parietal lobule; ILF = inferior longitudinal fasciculus; FA = fractional anisotropy; fasc = fasiculus/fasciculi; FC = functional connectivity; M = mean; MA = meta-analysis; MD = mean diffusivity; na = not available; MFG = medial frontal gyrus; mPFC = medial prefrontal cortex; MRS = magnetic resonance spectroscopy; MTL = medial temporal lobe; NAPLS = North American Prodrome Longitudinal Study; n.s. = not significant; PET = positron emission tomography; QR = quantitative review; RD = radial diffusivity; SFG = superior frontal gyrus; SLF = superior longitudinal fasciculus; SR = systematic review; SS = single study; STG = superior temporal gyrus; STS = superior temporal sulcus; sup = superior; temp = temporal; w = with; wm = white matter.

^aincludes high-risk groups other than CHR.