Editors' Introduction: Schizophrenia and Toxoplasmosis

Extract

This issue of Schizophrenia Bulletin includes articles on a possible infectious cause of schizophrenia. This approach follows a lead suggested by Emil Kraepelin and Eugen Bleuler a century ago. In the 1896 edition of his textbook, Kraepelin speculated that dementia praecox might be caused by a focal infection of bodily organs that then affected the brain as an autointoxication.1 Fifteen years later, Bleuler, in his Dementia Praecox, or The Group of Schizophrenias, suggested that “the connection of the disease to infectious processes equally needs further study … many writers assume that schizophrenia is caused by some physical weakness or possibly even by some infectious disease.”2

Toxoplasma gondii has emerged as an interesting candidate as a possible cause of some cases of schizophrenia. Past infectious research on schizophrenia has focused almost exclusively on bacteria and viruses, but T. gondii is a protozoa. Other protozoa known to chronically infect human brain tissue and cause behavioral changes include Plasmodium (malaria) and Trypanosoma (sleeping sickness).