Are There Neurochemical Indicators of Risk for Schizophrenia?

The genetic predisposition for certain forms of schizophrenia may involve heritable abnormalities in the functioning of neurochemical systems that project to and modulate limbic brain structures. However, with regard to both dopaminergic and serotonergic systems, there is little evidence that either basal cerebrospinal markers or plasma markers predict increased risk for the development of schizophrenia. Either their validity as correlates of brain monoamine function is uncertain or they are highly dependent upon clinical state. Both (1) platelet and neuroendocrine markers of serotonergic function and (2) an individual's capacity to decrease plasma homovanillic acid concentrations following neuroleptic blockade appear to be less state dependent, and these are worthy of further study as markers of risk for the development of schizophrenia.