Are there glutamate abnormalities in subjects at high risk mental state for psychosis? A review of the evidence.

New approaches to underlying alterations in psychosis suggest increasing evidence of glutamatergic abnormalities in schizophrenia and an association between these abnormalities and certain core psychopathological alterations such as cognitive impairment and negative symptoms. Proton magnetic resonance spectroscopy ((1)H MRS) is an MR-based technique that enables investigators to study glutamate function by measuring in vivo glutamatergic indices in the brain. In this article we review the published studies of (1)H MRS in subjects with an at-risk mental state (ARMS) for psychosis.