Biomarkers for psychosis

Abstract

Schizophrenia is a psychotic disorder characterized by alterations in perception, thought, and behavior. Although it is widely accepted to be a disorder of neuropathology, definitive biomarkers have yet to be established. This chapter provides a review of the current state of the field for biomarkers of psychosis research, with a focus on findings in schizophrenia. The review is limited to two broad domains, neuroanatomy and neurophysiology, as measured by three wellestablished methodologies, structural and function magnetic resonance imaging and electroencephalography. Studies of the neuroanatomy of schizophrenia consistently report volume reductions in temporal, medial temporal, and frontal cortices. Cognitive functional magnetic resonance imaging studies highlight prefrontal cortex inefficiency associated with executive functioning and cognitive control impairments, while functional connectivity magnetic resonance imaging studies highlight aberrant connectivity within and between intrinsic brain networks. Finally, electroencephalography studies in schizophrenia have established sensory gating deficits and impaired deviance detection as reflective of core deficits observed in the disorder. For each measure, the use as a potential biomarker is discussed in terms of treatment effects, clinical course, and specificity to psychosis. Current limitations and future directions of the field are discussed.