King's College London

Background/Aims: Previous diffusion tensor imaging (DTI) studies have shown microstructural changes in the brain white matter of at-risk mental state (ARMS) subjects for psychosis and patients with first-episode psychosis (FEP). However, only a few studies have been conducted in clinical high-risk samples and findings in both groups are inconsistent, in particular along the superior longitudinal fasciculus (SLF). Methods: This DTI study used tract-based spatial statistics (TBSS) to compare fractional anisotropy (FA) and mean diffusivity (MD) between ARMS subjects, untreated and antipsychotic-treated FEP patients and healthy controls (HC) across the whole brain and the SLF. Results: Compared to HC, ARMS and FEP patients showed increased FA and decreased MD in diverse regions across the whole brain including the SLF. FA in the SLF was positively correlated with positive psychotic symptoms in ARMS and FEP individuals. Furthermore, untreated but not treated FEP patients showed increased FA in the left inferior longitudinal fasciculus and right SLF. Conclusion: This study revealed increased FA and decreased MD in early stages of psychosis in widespread white matter tracts including the SLF. Our findings further suggest that microstructural changes in the SLF are probably related to state-dependent psychopathology.