Prenatal Infection and Adult Schizophrenia

Prenatal infectious and nutritional factors and risk of adult schizophrenia

Schizophrenia is a severely disabling psychiatric disorder. Despite a considerable amount of research on the underpinnings of the disorder, its etiology and pathogenesis remain unknown. In utero exposures, including infection and nutritional deficiencies, are emerging important risk factors for schizophrenia, in which neurodevelopmental influences probably play an important role. Our group and others have embarked on investigations aimed at identifying these risk factors and examining the mechanisms by which they increase vulnerability to this disorder. This work has the potential to lead to strategies aimed at preventing this disorder and to reveal new molecular targets for pharmacotherapeutic intervention.

Prenatal risk factors and schizophrenia

This article highlights major research findings that indicate a relation between prenatal environmental factors and the risk of adult schizophrenia. Evidence suggests that schizophrenia may have its origins in early maldevelopment of the brain. However, the factors responsible for this devastating disorder remain unknown. While genes clearly play a causal role, there is likely an environmental contribution as well. We discuss the evidence for several candidate environmental exposures that occur during prenatal life and that may modify the risk for developing schizophrenia. The main challenge of this type of research, termed risk-factor epidemiology, is to generate and test such exposures in subjects with schizophrenia, in order to develop preventive strategies and better understand the mechanisms that lead to this illness.

A possible relationship between Toxoplasma gondii and schizophrenia: A seroprevalence study

Objective. Schizophrenia is a pervasive neuropsychiatric disease of uncertain etiology. We aimed to investigate a possible association between Toxoplasma gondii infection and schizophrenia in this study. Method. We selected individuals with schizophrenia (n=88) and tested them with commercially available enzyme-linked immunosorbent assay (ELISA) for anti-Toxoplasma IgG and IgM antibodies and compared these seropositivity rate to those of controls without psychiatric disease (n=88). Results. The rate of IgG antibody in the schizophrenia patients (47.7%) was higher than the control groups (20.4%) (P<0.001). We did not find any anti-Toxoplasma IgM seropositivity in both schizophrenia patients and control group. In schizophrenic patients with and without anti-Toxoplasma IgG groups statistical analysis did not reveal any correlation between demographic variables and Toxoplasma infection. Conclusion. Our findings supported previous studies indicate that T.gondii may play a role in etiopathogenesis in some cases of schizophrenia.

Environmental risk factors for psychosis

Genetic factors are clearly important in the etiology of schizophrenia, but the environment in which an individual's genes find expression is also crucial to the development of the illness. In this review of environmental risk factors for schizophrenia, we consider risks operating prenatally and perinatally, during childhood, and then later in life prior to illness onset. Some of these risk factors have been well documented, for example, early hazards causing fetal growth retardation or hypoxia, and hazards nearer the onset of illness like drug abuse and migration. Others are much less certain. The importance of interaction between genetic and environmental risk is, however, undoubtedly important and there is emerging evidence for this from a range of sources. As the etiology of schiz-ophrenia is unraveled, the picture becomes more complex, but also more obviously relevant to the plight of the individual patient.

In utero infection and adult schizophrenia

We review emerging evidence indicating that in utero exposure to infection is a risk factor for schizophrenia. It is hypothesized that a prenatal infection increases the liability to schizophrenia in adulthood by adversely affecting the maturation of critical brain structural and functional components implicated in the pathogenesis and pathophysiology of the disorder. Early evidence for a role of in utero infection includes investigations linking schizophrenia with birth during the winter and in urban regions, and ecologic studies demonstrating associations between influenza epidemics and births of pre-schizophrenic patients. The findings of the latter studies are, however, equivocal. To more rigorously address this question, our group has used increasingly sophisticated research designs that incorporate more refined measures of exposure and outcome, and continuous follow-up of treated cases. This work has already yielded several intriguing findings, including associations between schizophrenia and two in utero infections--rubella and respiratory infection. We also describe our ongoing birth cohort investigations that are expected to advance this work further, including studies that utilize maternal serum samples drawn during pregnancy of offspring who were later diagnosed with schizophrenia.