Association between Suicide and Toxoplasma gondii Seropositivity

This study aimed to determine the association between suicide and Toxoplasma gondii (T. gondii) seropositivity. Serum samples of 89 decedents who committed suicide (cases) and 58 decedents who did not commit suicide (controls) were tested for anti-T. gondii IgG and IgM antibodies using enzyme-linked immunosorbent assays. Anti-T. gondii IgM antibodies were further detected by enzyme-linked fluorescence assay (ELFA). A total of 8 (9.0%) of the 89 cases and 6 (10.3%) of the 58 controls were positive for anti-T. gondii IgG antibodies (OR: 0.85; 95% CI: 0.28-2.60; p = 0.78). Anti-T. gondii IgG levels were higher than 150 IU/mL in two (2.2%) cases and in five (8.6%) controls (OR: 0.24; 95% CI: 0.04-1.30; p = 0.11). Anti-T. gondii IgM antibodies were not found in any case or control using the enzyme immunoassay and were found in only one (1.7%) control using ELFA (p = 0.39). Rates of IgG seropositivity and high levels of anti-T. gondii antibodies were similar in cases and in controls regardless of their sex or age groups. The results do not support an association between T. gondii seropositivity and suicide. However, the statistical power of the test was low. Further research is necessary to confirm this lack of association.