Toxoplasma gondii as a Risk Factor for Schizophrenia and Psychosis

Abstract

Toxoplasma gondii is a parasitic protozoan found in nearly one-third of the population worldwide. Although most individuals with a latent Toxoplasma gondii infection are asymptomatic, several studies have linked infection with the parasite to several forms of psychopathology, including anxiety, personality disorders, bipolar disorder, schizophrenia, and suicidality. Other studies have established that individuals with schizophrenia are at nearly three times greater odds of being infected with Toxoplasma gondii than individuals without schizophrenia. Only recently has research begun to understand the common etiology of Toxoplasma gondii infection and schizophrenia, as well as other psychotic disorders. The current study examined the prevalence of Toxoplasma gondii in an urban, help-seeking sample of adolescents and young adults with varying levels of risk for psychosis, as well as a range of psychosis-risk diagnoses. The prevalence of Toxoplasma gondii infection in this sample was lower than expected and neither schizophrenia-risk nor psychosis-risk showed a significant relation with Toxoplasma gondii. Explanations for the low prevalence of Toxoplasma gondii in this sample were explored.