Developmental pathology, dopamine, and stress: a model for the age of onset of schizophrenia symptoms.

It is unknown why the onset of schizophrenia is typically during late adolescence or early adulthood. The fact that numerous brain maturational processes normally occur during this age period has led researchers to postulate how such processes may be related to the onset of symptoms. To help elucidate the question of age of onset, we selectively review schizophrenia-associated abnormalities of dopamine and related systems, including glutamate and hypothalamic-pituitary-adrenal systems; relevant models of pathophysiology; and the systems' developmental aspects. Based on current findings and conceptualizations, a model is then proposed in which, during adolescence, interactive pathological and normal adolescence-associated processes trigger a positive feedback system that results in a rapid increase in pathology that is proposed to underlie the development of active psychotic symptoms during late adolescence or early adulthood.