The association between toxoplasma and the psychosis continuum in a general population setting

Abstract

Toxoplasma gondii infection is associated with increased risk for psychosis. However, the possible association between T. gondii and psychotic-like symptoms in the general adult population is unknown. We investigated whether T. gondii is associated with psychotic-like symptoms and psychosis diagnoses using data from Health 2000, a large cross-sectional health survey of the Finnish general population aged 30 and above. Seropositivity to toxoplasma was defined as a cutoff of 50IU/ml of IgG antibodies. Lifetime psychotic-like symptoms were identified with section G of the Composite International Diagnostic Interview, Munich version (M-CIDI). Symptoms were considered clinically relevant if they caused distress or help-seeking or there were at least three of them. Lifetime psychotic disorders were screened from the sample and were diagnosed with DSM-IV using SCID-I interview and information from medical records. All data were available for 5906 participants. We adjusted for variables related to T. gondii seropositivity (age, gender, education, region of residence, cat ownership, and C-reactive protein measuring inflammation) in regression models. We found that T. gondii seropositivity was significantly associated with clinically relevant psychotic-like symptoms (OR 1.77, p=0.001) and with the number of psychotic-like symptoms (IRR=1.55, p=0.001). The association between toxoplasma and diagnosed psychotic disorders did not reach statistical significance (OR 1.45 for schizophrenia). In a large sample representing the whole Finnish adult population, we found that serological evidence of toxoplasma infection predicted psychotic-like symptoms, independent of demographic factors and levels of C-reactive protein. Toxoplasma infection may be a risk factor for manifestation of psychotic-like symptoms.

Exposure to common infections and risk of suicide and self-harm: a longitudinal general population study

“…Toxoplasma may be associated with several mental disorders [4][5][6][7]. We have previously published cross-sectional results on the association between IgG antibodies against T. gondii and anxiety disorders and depressive and psychotic-like symptoms [1,8]. Furthermore, CMV has been linked to psychiatric disorders [9][10][11][12].…”

Toxoplasma Immunomodulation Related to Neuropsychiatric Diseases

“…Recent studies try to prove this relationship. Study of Lindgren and collaborators demonstrated a significant association between T. gondii seropositivity and psychotic symptoms [76]. Vlatkovic and collaborators find an increased prevalence of T. gondii infection in a patient with Schizophrenia [77].…”

From Infection to the Microbiome: An Evolving Role of Microbes in Schizophrenia

“…Another microbe, the neurotropic parasite, Toxoplasma gondii , has been repeatedly implicated in schizophrenia etiopathogenesis, and this relationship is reviewed in numerous analyses and meta-analyses (Arias et al 2012 ; Monroe et al 2015 ; Severance et al 2016b ; Torrey et al 2007 , 2012 ). Exposure to this parasite has been associated with important clinical effects such as decreased cognition, suicidal behavior, and severity of the psychotic symptoms (Dickerson et al 2017b ; Esshili et al 2016 ; Hamdani et al 2017 ; Kannan et al 2017 ; Lindgren et al 2018 ). Studies have also uncovered evidence for heightened exposures to fungal species such as the yeasts, Candida albicans and Saccharomyces cerevisiae , in individuals with schizophrenia (Severance et al 2012 , 2016a ).…”