There is increasing evidence that changes in connections linking brain regions, as well as grey matter volumetric abnormalities are important in schizophrenia. The extent to which these are related to being at risk of psychosis as opposed to having a psychotic disorder is unclear. We will review the diffusion tensor imaging (DTI) findings which inform us about white matter integrity and organization, and relate it to our own work which compares grey matter volumes and white matter integrity in people at high risk of psychosis, patients with first episode psychosis, and healthy volunteers. We will also discuss the relationship of these findings to clinical symptoms and outcome.

30 subjects with an ‘at risk mental state’ (PACE criteria), 15 first psychotic episode patients and 30 controls were studied using an SPGR sequence and DTI.

Both the volumetric and DTI datasets were analysed using voxel based techniques in standard space. There were frontal and temporal grey matter reductions in the first episode group and more modest temporo-parietal volume reductions in the ‘at risk’ group. The first episode group had reduced fractional anisotropy in the superior longitudinal fasciculus bilaterally, left anterior corpus callosal and right superior fronto-occiptal tracts relative to controls, with qualitatively similar but less severe reductions in the ‘at risk’ subjects.

Abnormalities in the frontal and temporal grey matter and the tracts connecting them were evident in patients with first episode schizophrenia, with similar but less marked abnormalities in subjects with an ‘at risk’ mental state.