Toxoplasma gondii infection and suicide attempts: a case-control study in psychiatric outpatients

The association of Toxoplasma gondii infection with suicide attempts has been scarcely evaluated. Two hundred eighty-three psychiatric outpatients (156 patients with history of suicide attempt and 127 control patients without history of suicide attempt) were examined with enzyme-linked immunoassays for Toxoplasma immunoglobulin G (IgG) and IgM antibodies. Seroprevalences of Toxoplasma IgG and IgM in the cases and the controls were similar: 7 (4.5%) and 3 (1.9%) vs. 10 (7.9%) and 3 (2.4%) (p = 0.23 and p = 0.55), respectively. In contrast, the Toxoplasma IgG levels higher than 150 IU/ml were more frequently observed in the cases than in the controls (100% vs. 50%, respectively; p = 0.04). The seroprevalence of Toxoplasma infection increased with age and with the number of suicide attempts. Toxoplasma seropositivity was associated with reflex impairment, national trips, and snake meat consumption. Our results suggest that although seroprevalence of Toxoplasma infection is not associated with suicide attempts, a high anti-Toxoplasma antibody level is, therefore warranting further research.