Toxoplasma gondii (T.gondii) is an obligate intracellular protozoan parasite infecting one-third of the world population, residing relatively silently in the brain of the immunocompetent host. We hypothesized that T.gondii seropositivity and serointensity are associated with having a history of attempting suicide and, in those attempting suicide, a greater number of attempts. T.gondii seropositivity and antibody titers were compared between (a) patients with recurrent mood disorders with history of suicide attempt (99 individuals) versus (b) patients with recurrent mood disorders without history of suicide attempt (119 individuals), and (c) healthy controls (39 individuals). Diagnosis was made using the Structured Clinical Interview for DSM-IV. Statistical methods included chi square, analysis of variance, and linear and logistic regression analyses. Suicide attempters had higher T.gondii antibody titers than nonsuicide attempters (p = 0.004). The logistic regression analysis revealed a predictive association between titers of anti- T.gondii antibodies and history of suicide attempt with OR = 1.55 (1.14–2.12), p = 0.006. No significant relationship was found between T.gondii seropositivity and suicide attempt status, number of prior suicide attempts, and recurrent mood disorder diagnosis. Although preliminary and bearing replication, this is the first report, to our knowledge, of an association between attempting suicide and T. gondii.
*Mood and Anxiety Program, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD; †Stanley Division of Developmental Neurovirology, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD; ‡Epidemiology and Preventive Medicine, University of Maryland School of Medicine, Baltimore, MD; §Stanley Research Center, Sheppard Pratt Health System, Baltimore, MD; and ¶Department of Family and Community Health, University of Maryland School of Nursing, Baltimore, MD.
Supported by a NARSAD Independent Award (to T.T.P.), grants R21 MH075891 and R01MH074891 from the National Institute of Mental Health (to T.T.P.) and the Stanley Medical Research Institute (to F.B.D. and R.H.Y.).
Send reprint requests to Teodor T. Postolache, MD, Mood and Anxiety Program (MAP), Department of Psychiatry, University of Maryland School of Medicine, 685 West Baltimore St, MSTF Building Room 502, Baltimore, MD 21201. E-mail: firstname.lastname@example.org.