The utility of gene expression in blood cells for diagnosing neuropsychiatric disorders

Objective diagnostic tools are required for neuropsychiatric disorders. Gene expression in blood cells may provide such a tool and has already been used to construct classifiers capable of diagnosing many human diseases. This chapter discusses the use of microarray gene expression data to construct diagnostic classifiers for neuropsychiatric disorders. The potential pitfalls of microarray gene expression analysis and the experimental design and methods suitable for classifier construction are described in detail. A review of studies that have analyzed gene expression in blood cells from patients with neuropsychiatric disorders is presented with an emphasis on the feasibility of generating a diagnostic classifier for schizophrenia. Finally, the future directions of the field are discussed with respect to using blood gene expression to tailor antipsychotic medications to individual patients, applying microRNA expression for diagnostic purposes, as well as the implications of next-generation sequencing technologies for gene expression analysis.