Schizophrenia affects a significant proportion of the population and current levels of
understanding of the illness is inadequate to treat it effectively. Converging lines of
evidence suggest that neuroinflammation occurs in schizophrenia, and specifically
over-activity of brain-resident immune cells called microglia. It is however unclear whether
activated microglia play a primary role in schizophrenia, or whether this is a secondary
phenomenon of no pathophysiological significance. The investigators therefore plan to test
the effect of a monoclonal antibody (natalizumab) on psychotic symptoms in a cohort of first
episode psychosis patients.