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07-09-2011 | Mental health | Article

T. gondii serology linked to suicide attempts in schizophrenia patients


Free abstract

MedWire News: Infection with the parasite Toxoplasma gondii is associated with a history of suicide attempts in younger patients with schizophrenia, research suggests.

Previous studies have indicated that schizophrenia patients have a higher prevalence of T. gondii antibodies than those without the condition, and that the prevalence of T. gondii is positively associated with US national suicide rates among women of postmenopausal age," explain Teodor Postolache (University of Maryland School of Medicine, Baltimore, USA) and team.

But they add that "no previous study has examined the association of T. gondii with suicidal behavior in schizophrenia patients."

To address this, the researchers studied 950 individuals (600 men) with schizophrenia who were aged an average of 38 years. Of these, 351 (37%) had a history of suicide attempts, while the remaining 599 (63%) patients did not.

Blood samples were collected from all of the participants and assessed for immunoglobulin G (IgG) antibodies to T. gondii using solid-enzyme immunoassay. Seropositivity was defined as a T. gondii IgG titer ≥0.8.

The team also assessed the participants for serum levels of antibodies to two neurotropic viruses (cytomegalovirus [CMV] and herpes simplex virus type 1 [HSV-1]) and to gliadin (wheat protein).

The researchers found that T. gondii seropositivity was significantly associated with a history of suicide attempts in patients younger than the median age of 38 years, at an adjusted odds ratio of 1.57.

T. gondii serointensity was also significantly associated with a history of suicide attempts in the younger age group.

There were no significant associations between T. gondii seropositivity or serointensity and a history of suicide attempts among patients aged 38 years or older.

Seropositivity for CMV, HSV-1, and gliadin was not associated with a history of suicide attempts in any age group.

Postolache and team conclude in the journal Schizophrenia Research: "Adding to the emerging body of evidence connecting T. gondii with suicidal behavior, T. gondii antibodies were found to be associated with suicide attempt history in younger schizophrenia patients."

They add: "If the findings from the current study are replicated (in future longitudinal studies) and become established, then the implications for prevention and treatment are considerable."

MedWire ( is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2011

By Mark Cowen

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