Structural brain abnormalities in individuals with an at-risk mental state who later develop psychosis.

BACKGROUND Neuroanatomical abnormalities are a well-established feature of schizophrenia. However, the timing of their emergence and the extent to which they are related to vulnerability to the disorder as opposed to psychotic illness itself is unclear. AIMS To assess regional grey matter volume in the at-risk individuals who subsequently developed psychosis. METHOD Magnetic resonance imaging data from at-risk individuals who developed psychosis (n=12) within the following 25 months were compared with data from healthy volunteers (n=22) and people with first-episode psychosis (n=25). RESULTS Compared with healthy volunteers, individuals who subsequently developed psychosis had smaller grey matter volume in the posterior cingulate gyrus, precuneus, and paracentral lobule bilaterally and in the left superior parietal lobule, and greater grey matter volume in a left parietal/posterior temporal region. Compared with first-episode patients, they had relatively greater grey matter volume in the temporal gyrus bilaterally and smaller grey matter volume in the right lentiform nucleus. CONCLUSIONS Some of the structural brain abnormalities in individuals with an at-risk mental state may be related to an increased vulnerability to psychosis, while others are associated with the development of a psychotic illness.