Large-scale study of Toxoplasma and Cytomegalovirus shows an association between infection and serious psychiatric disorders

Brain Behav Immun. 2019 Jul;79:152-158. doi: 10.1016/j.bbi.2019.01.026. Epub 2019 Jan 29.

Abstract

Background: Common infectious pathogens have been associated with psychiatric disorders, self-violence and risk-taking behavior.

Methods: This case-control study reviews register data on 81,912 individuals from the Danish Blood Donor Study to identify individuals who have a psychiatric diagnosis (N = 2591), have attempted or committed suicide (N = 655), or have had traffic accidents (N = 2724). For all cases, controls were frequency matched by age and sex, resulting in 11,546 participants. Plasma samples were analyzed for immunoglobulin G (IgG) antibodies against Toxoplasma gondii and cytomegalovirus (CMV).

Results: T. gondii was detected in 25·9% of the population and was associated with schizophrenia (odds ratio [OR], 1·47; 95% confidence interval [CI], 1·03-2·09). Accounting for temporality, with pathogen exposure preceding outcome, the association was even stronger (IRR, 2·78; 95% CI, 1·27-6·09). A very weak association between traffic accident and toxoplasmosis (OR, 1·11; 95% CI, 1·00-1·23, p = 0.054) was found. CMV was detected in 60·8% of the studied population and was associated with any psychiatric disorder (OR, 1·17; 95% CI, 1·06-1·29), but also with a smaller group of neurotic, stress-related, and somatoform disorders (OR, 1·27; 95% CI, 1·12-1·44), and with attempting or committing suicide (OR, 1·31; 95% CI, 1·10-1·56). Accounting for temporality, any psychiatric disorder (IRR, 1·37; 95% CI, 1·08-1·74) and mood disorders (IRR, 1·43; 95% CI, 1·01-2·04) were associated with exposure to CMV. No association between traffic accident and CMV (OR, 1·06; 95% CI, 0·97-1·17) was found.

Conclusions: This large-scale serological study is the first study to examine temporality of pathogen exposure and to provide evidence of a causal relationship between T. gondii and schizophrenia, and between CMV and any psychiatric disorder.

Keywords: Antibodies; Cytomegalovirus; Infection; Parasite, psychiatric disorders; Serology; Suicide; Toxoplasma gondii; Toxoplasmosis; Traffic accidents.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Accidents, Traffic
  • Adolescent
  • Adult
  • Aged
  • Antibodies, Protozoan / blood
  • Antibodies, Protozoan / immunology
  • Case-Control Studies
  • Cytomegalovirus / immunology*
  • Cytomegalovirus / pathogenicity
  • Denmark / epidemiology
  • Female
  • Humans
  • Immunoglobulin G / blood
  • Immunoglobulin G / immunology
  • Male
  • Mental Disorders / etiology*
  • Mental Disorders / immunology
  • Mental Disorders / microbiology
  • Middle Aged
  • Odds Ratio
  • Risk Factors
  • Schizophrenia / etiology
  • Schizophrenia / immunology
  • Schizophrenia / microbiology
  • Suicide, Attempted
  • Suicide, Completed
  • Toxoplasma / immunology*
  • Toxoplasma / pathogenicity
  • Toxoplasmosis / blood
  • Toxoplasmosis / immunology

Substances

  • Antibodies, Protozoan
  • Immunoglobulin G