Psychosis risk is associated with decreased white matter integrity in corticostriatal tracts
Psychosis is associated with increased striatal dopamine and it is thought that altered connectivity between the striatum and the cortex could contribute to psychosis. In particular, there is theory and research linking psychosis to altered connectivity between the striatum and several cortical networks, especially the limbic, default mode, and frontoparietal networks. However, it is still unclear whether psychosis risk is associated with altered white matter connectivity between the striatum with any cortical region. Further, no previous study has directly examined whether psychosis risk is associated with altered connectivity with specific cortical networks. In the current study, I examined integrity of white matter tracts in psychosis risk (n=18) and non-psychosis risk comparison participants (n=19). Tracts were identified using probabilistic tractography. I found that psychosis risk was associated with significantly decreased connectivity between the striatum and the limbic cortical network, especially in the right external capsule and with connections to the right prefrontal cortex. There was a trend for psychosis risk to also be associated with decreased striatal-default mode network connectivity. However, there were no significant group differences for striatal-frontoparietal network connectivity. Hence, the current research suggests that psychosis risk is associated with decreased white matter integrity in networks involved in processing emotional and personally relevant information.