"Latent" infection with Toxoplasma gondii: association with trait aggression and impulsivity in healthy adults.

BACKGROUND: Latent chronic infection with Toxoplasma gondii (T. gondii), a common neurotropic pathogen, has been previously linked with suicidal self-directed violence (SSDV). We sought to determine if latent infection with T. gondii is associated with trait aggression and impulsivity, intermediate phenotypes for suicidal behavior, in psychiatrically healthy adults. METHODS: Traits of aggression and impulsivity were analyzed in relationship to IgG antibody seropositivity for T. gondii and two other latent neurotropic infections, herpes simplex virus 1 (HSV1) and cytomegalovirus (CMV). One thousand community-residing adults residing in the Munich metropolitan area with no Axis I or II conditions by SCID for DSM-IV (510 men, 490 women, mean age 53.6 ± 15.8, range 20-74). Plasma samples were tested for IgG antibodies to T. gondii, HSV-1 and CMV by ELISA. Self-reported ratings of trait aggression scores (Questionnaire for Measuring Factors of Aggression [FAF]) and trait impulsivity (Sensation-Seeking Scale-V [SSS-V]) were analyzed using linear multivariate methods. RESULTS: T. gondii IgG seropositivity was significantly associated with higher trait reactive aggression scores among women (p < .01), but not among men. T. gondii-positivity was also associated with higher impulsive sensation-seeking (SSS-V Disinhibition) among younger men (p < .01) aged 20-59 years old (median age = 60). All associations with HSV-1 and CMV were not significant. CONCLUSIONS: Aggression and impulsivity, personality traits considered as endophenotypes for SSDV, are associated with latent T. gondii infection in a gender and age-specific manner, and could be further investigated as prognostic and treatment targets in T. gondii-positive individuals at risk for SSDV.

Phadiatop Seropositivity in Schizophrenia Patients and Controls: A Preliminary Study.

There is a dearth of information on the association of atopy with schizophrenia. The few available studies used population-based registers to classify the atopy status of the patients but this strategy is not reliable. This study measured seropositivity with a multiallergen screen of allergen specific IgE antibodies in schizophrenia patients versus healthy controls. A subset of 66 schizophrenia patients and 34 healthy controls were randomly selected from a large comparative study of schizophrenia patients and controls. The Phadiatop multi-allergen screen was performed on sera from all the participants to assess their atopic status. Logistic regression was used to calculate the odds ratio for the association of schizophrenia with Phadiatop seropositivity as a measure of atopy. The prevalence of Phadiatop seropositivity was significantly lower (χ2 4.59, p = 0.032) and there was a reduced odds ratio for atopy in schizophrenia patients relative to controls (OR 0.40; 95% CI 0.17 to 0.94, p = 0.036). Though limited by a relatively small sample size and potentially confounded by anti-psychotic medications, this study suggests that the prevalence of atopy is lower in patients with schizophrenia. Replicating these results in larger samples could add to our growing understanding of immunological implications in mental illness.