Toxoplasma gondii infection and self-directed violence in mothers.

CONTEXT Two studies based on clinical samples have found an association between Toxoplasma gondii infection and history of suicide attempt. To our knowledge, these findings have never been replicated in a prospective cohort study. OBJECTIVE To examine whether T gondii–infected mothers have an increased risk of self-directed violence, violent suicide attempts, and suicide and whether the risk depends on the level of T gondii IgG antibodies. DESIGN 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. MAIN OUTCOME MEASURES Incidence rates of self-directed violence, violent suicide attempts, and suicide in relation to T gondii seropositivity and serointensity. 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). CONCLUSION Women with a T gondii infection have an increased risk of self-directed violence.