Psychotic experiences in childhood are associated with increased structural integrity of the left arcuate fasciculus - A population-based case-control study.

Around 1 in 5 children under 13 years old experience sub-clinical psychotic experiences (PEs) like hallucinations and delusions. While PEs in childhood are a significant risk factor for adult psychotic disorders, the majority of those experiencing childhood PEs do not develop a psychotic disorder. Individual differences in regional brain maturation rates may be responsible for this age-related and often transient emergence of PEs. Fronto-temporal association tracts undergo extensive maturation and myelination throughout childhood and adolescence, thus we focus on individual differences in one such tract, the arcuate fasciculus. A normative population-based sample of children (aged 11-13) attended a clinical interview and MRI (n = 100), 25 of whom were identified as reporting strong PEs. This group had reduced mean and radial diffusivity in the arcuate fasciculus compared with a group of matched controls (n = 25) who reported no PEs. The group difference was greater in the left hemisphere than the right. Mediation analyses showed that this group difference was driven predominantly by perceptual disturbances and an along-tract analysis showed that the group difference was greatest approximately halfway between the frontal and temporal termination points of the tract (adjacent to the left lateral ventricle). This study is the first to investigate links between arcuate fasciculus diffusivity and psychotic experiences in a population sample of children.