Indeed, microarray analysis of gene expression differences associated with schizophrenia indicated that the most altered group of genes are those involved in presynaptic secretory function and in particular the regulator of G-protein signalling 4 gene (RGS4), encoding a GTPase activating protein, the expression of which was dramatically reduced in schizophrenia [22], [23]. This evidence concerns the gene RGS4 and schizophrenia.