Toxoplasma gondii Antibody Titers and History of Suicide Attempts in Patients With Recurrent Mood Disorders

Abstract

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 ϭ 0.004). The logistic regression analysis revealed a predictive association between titers of anti-T.gondii antibodies and history of suicide attempt with OR ϭ 1.55 (1.14 -2.12), p ϭ 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.

Effects of Toxoplasma gondii infection on anxiety, depression and ghrelin level in male rats

“…Patients with recurrent mood disorders with history of suicide attempt had higher T. gondii antibody titers than patients with recurrent mood disorders without history of suicide attempt (Arling et al 2009). In a case-control study, the association between latent toxoplasmosis and cognitive performance with a battery of standardized, widely employed neuropsychological tests were assessed.…”

“…gondii can alter brain function and induce changes in the behavior of its intermediate hosts (Mortensen et al 2007;Kar and Misra 2004;Arling et al 2009). In male LongEvans rats, Latent Toxoplasma infection resulted to reduced the normal aversion to cat odor and converted it into a mild attraction (Vyas et al 2007).…”

“…It has been reported a depressed patient with toxoplasma seropositivity improved only after treatment by anti-toxoplasma drugs (Kar and Misra 2004). Furthermore, it has been shown that T. gondii IgG antibody titer is higher in suicide attempter patients than non-suicide attempter individuals (Arling et al 2009). Therefore, all above studies show there is association between T. gondii infection and onset of anxiety and depression.…”

Toxoplasma gondii Seroprevalence in the United States 2009–2010 and Comparison with the Past Two Decades

“…3 In addition, T. gondii infection has been repeatedly found to be associated with mental illnesses, including schizophrenia, self-harm, and bipolar depression, although the evidence is not yet sufficient to imply a causal relationship. [4][5][6][7][8] Periodically, the Centers for Disease Control and Prevention (CDC) tests serum samples from the National Health and Nutrition Examination Survey (NHANES) for T. gondii antibodies to estimate the prevalence of T. gondii infection in the United States. Once infected, people generally retain a chronic infection, particularly in the cells of the muscles and brain.…”

Neurophysiological Changes Induced by Chronic <em>Toxoplasma gondii</em> Infection

“…Chronic T. gondii infection in the human population has been correlated with a diverse range of human diseases, including Alzheimer's and Huntington's [12,13]. The association between T. gondii infection and mental health disorders such as depression, psychosis, self-directed violence and schizophrenia have been widely studied [14][15][16][17][18]. Schizophrenia is the most extensively investigated of these; indeed two meta-analyses of the association collectively spanning 70 studies over 55 years concluded that there is a positive correlation between T. gondii seropositivity and schizophrenia [19,20].…”