Toxoplasma Gondii and Elevated Suicide Rates

The three studies that Wikipedia presents in support of the observation that T. gondii infection is associated with higher suicide rates:

J Clin Psychiatry 2012;73(8):1069-1076

This cross-sectional, observational study compared T gondii serointensity and seropositivity in plasma from 54 adult suicide attempters (inpatients at Lund University Hospital, Lund, Sweden) and 30 adult control subjects (randomly selected from the municipal population register in Lund, Sweden) recruited between 2006 and 2010.

Data were analyzed using multivariable logistic regression to investigate the association between T gondii serointensity or seropositivity and a history of nonfatal suicidal self-directed violence; multivariable linear regression was used to explore the relationship between T gondii serointensity or seropositivity and the SUAS-S. Both regression models included sex, age, and body mass index as covariates.

Seropositivity of T gondii (adjusted odds ratio [OR] = 7.12; 95% CI, 1.66–30.6; P =.008) and serointensity of T gondii (adjusted OR = 2.01; 95% CI, 1.09–3.71; P = .03) were positively associated with a history of nonfatal suicidal self-directed violence.

Arch Gen Psychiatry. 2012;69(11):1123-1130

Register-based prospective cohort study. Women were followed up from the date of delivery, 1992 to 1995 until 2006.

Setting Denmark.

Participants A cohort of 45 788 women born in Denmark whose level of Toxoplasma -specific IgG antibodies was measured in connection with child birth between 1992 and 1995.

Results T gondii– infected mothers had a relative risk of self-directed violence of 1.53 (95% CI, 1.27-1.85) compared with noninfected mothers, and the risk seemed to increase with increasing IgG antibody level. For violent suicide attempts, the relative risk was 1.81 (95% CI, 1.13-2.84) and for suicide, 2.05 (95% CI, 0.78-5.20). A similar association was found for repetition of self-directed violence, with a relative risk of 1.54 (95% CI, 0.98-2.39).