To gain more insight in the role of herpes viruses in the etiology of schizophrenia, the effect of a herpes virus infection on behavior and brain function was examined in rats. We have shown that herpes virus infection of the brain resulted in focal areas of brain inflammation. This was accompanied by behavioral changes and changes in the neurotransmitters dopamine and glutamate, which are also disturbed in schizophrenia. Treatment of herpes virus infected rats with clozapine and risperidone, used for treatment of schizophrenia, resulted in a decrease in brain inflammation. These studies showed that herpes viruses induce physiological changes, resembling those seen in schizophrenia. In addition, we have shown that inflammation is present in the hippocampus of schizophrenic patients, during psychosis. Furthermore, evidence was found for the presence of replicating herpes viruses in the temporal cortex. The hippocampal inflammation in schizophrenic patients may be caused by replicating herpes viruses, since the hippocampus is part of the temporal lobe.