Factors in the etiology of schizophrenia: Genes, parental age, and environment

Schizophrenia is a brain disorder with a complex etiology believed to have both genetic and environmental risk factors. Although the precise pathology of the disease and the mechanisms that cause the emergence of symptoms remain elusive, understanding the causes of schizophrenia and its risk factors have evolved considerably over the past decade. The discussion has shifted from the reductionist "genes versus environment" debate to a more integrative approach, ie, the functions of susceptibility genes, epigenetics and paternal age, and toxic exposures throughout early development. This article discusses evidence for three major categories of risk factors, including genetic contributions, the role of paternal age and potential mechanisms by which it exerts its influence on risk, and new findings on the role of environmental exposures.