Can Influenza “Cause” Schizophrenia?
Although Menninger considered many avenues by which the Spanish Influenza of 1918 could lead to the development of dementia praecox, neither he nor any of his contemporary investigators raised the possibility that the influence of influenza on the etiology of schizophrenia could occur in utero. Although this idea has been debated in the scientific literature, many studies have documented that schizophrenia occurs more frequently in children born in winter and early spring when viral infections are more prevalent.12 Among 25 investigations of the incidence of schizophrenia in the offspring of women who were thought to have contracted influenza during pregnancy, approximately 50% reported positive associations.13 Reliably documenting maternal influenza exposure in these studies has been challenging because viral exposure has been generally based on participants’ self-reports of infection or on occurrences of influenza epidemics contemporaneous with their pregnancies. To counter this prob
