Fig. 1.

Schematic illustration of a two-hit model of schizophrenia. The model proposes that there is a first hit via prenatal genetic or environmental disruptions in the developmental central nervous system. As a result, the system is primed with vulnerable neuronal circuitry that is subsequently exacerbated by a second hit to the system via potential environmental factors that lead to the onset of schizophrenia systems, specifically during adolescence. Adapted from Maynard, Sikich, Lieberman, and LaMantia (2001).