Stalking the schizovirus.

The possibility that some cases of schizophrenia are caused by a chronic infectious process of the central nervous system is being explored. This hypothesis was popular in the early years of the 19th century and has been revived as certain properties of viruses have become better understood (e.g., neurotropism, latency, and ability to alter cell enzymes without affecting cell structure). Schizophrenia could theoretically be caused by infections occurring either in utero or at any time up to the age of onset. Research on a possible viral etiology of some cases of schizophrenia is being carried out using both indirect measures (seasonality of schizophrenic births, prevalence studies, immunological abnormalities, antiviral effects of antipsychotic drugs, and studies of identical twins) as well as direct measures (neuropathology, transmission to laboratory animals, and detection of the viral genome, antigen, or antibody).