 From these studies we have hypothesized that in schizophrenia an over-abundance of dopamine in the ventral striatum interferes with normal functioning by limiting the transmission of glutamate. Putatively, antipsychotic medications may decrease the symptoms of schizophrenia by restoring glutamatergic activity in the ventral striatum and projected areas, such as the anterior cingulate cortex and hippocampus. We have hypothesized that those individuals responding favorably to antipsychotic drug therapy will display greater glutamate activity in the ventral striatum due to dopamine blockade and the other regions receiving glutamate projections. This should lead to restored neuronal functioning in good responders when compared to treatment resistant and poor responders to antipsychotic drug treatment. We will test this hypothesis using complementary imaging and postmortem studies yielding data that will permit the formulation of a comprehensive model for antipsychotic drug responses in subjects with severe mental illness. 