Toxoplasma gondii infection and chronic schizophrenia: is there any association?

Background: Toxoplasma gondii (T. gondii) infection has been identified as a risk factor for schizophrenia. Objectives: Herein, we sought to evaluate the association between T. gondii infection and clinical symptoms and quality of life in patients with schizophrenia. Methods: We conducted a cross-sectional study with 48 patients with chronic schizophrenia and 40 controls. Peripheral blood was drawn, and IgM and IgG anti-T. gondii antibodies were evaluated by Enzyme-Linked Immunosorbent Assay (ELISA). Depressive, positive and negative symptoms were assessed, respectively, by the Calgary Depression Scale (CDS) and the Positive and Negative Syndrome Scale (PANSS). Cognitive performance was assessed in patients by the Brazilian version of the Schizophrenia Cognition Rating Scale (SCoRS-BR). Quality of life was assessed by the Brazilian version of the Quality of Life in Schizophrenia scale (QLS-BR). Results: The prevalence and titers of T. gondii IgM and IgG antibodies did not differ between patients and controls. The positive serology for T. gondii IgG antibodies was not associated with illness symptoms, cognitive performance, depressive symptoms or quality of life. Discussion: Our findings suggest that toxoplasmosis infection is not associated with severity of symptoms, quality of life, cognitive or depressive symptoms in schizophrenia patients.