RETROVIRUSES AND SCHIZOPHRENIA REVISITED

Both genetic and environmental factors appear to contribute to the cau sation of schizophrenia, Evidence indicating that fetal development is disrupted in schizophrenia and the finding of an excess of winter bir ths among schizophrenic patients have led to continued speculation tha t an intrauterine viral infection may cause developmental lesions, gen etic mutations, or persistent infections that lead to schizophrenia. C ertain unique characteristics of the retroviruses render them plausibl e as candidate ''schizoviruses'' and the involvement of an endogenous retrovirus would be compatible with some of the puzzling epidemiologic al findings in schizophrenia. Reverse transcriptase (RT) is a retrovir ally encoded enzyme essential for retroviral integration into host DNA , While attempts to detect retroviral infections by measuring RT activ ity in the peripheral lymphocytes and serum of schizophrenic patients have been unsuccessful, such negative findings may simply mean that th e virus is not active in peripheral lymphocytes, A more sensitive and comprehensive approach to detect a retrovirus is to search the genomes of schizophrenic patients directly for the presence of retroviral DNA sequences encoding RT and one possible approach is described. (C) 199 6 Wiley-Liss, Inc.