title: Combined Toxoplasma gondii seropositivity and high blood kynurenine--Linked with nonfatal suicidal self-directed violence in patients with schizophrenia.
abstract: Toxoplasma gondii (T. gondii) chronic infection and elevated kynurenine (KYN) levels have been individually associated with non-fatal suicidal self-directed violence (NF-SSDV). We aimed to test the hypothesis that the association between T. gondii seropositivity and history of NF-SSDV would be stronger in schizophrenia patients with high plasma KYN levels than in those with lower KYN levels. We measured anti-T. gondii IgG antibodies and plasma KYN in 950 patients with schizophrenia, and used logistic regression to evaluate the relationship between NF-SSDV and KYN in patients who were either seropositive or seronegative for T. gondii. For those with KYN levels in the upper 25th percentile, the unadjusted odds ratio for the association between NF-SSDV history and KYN in T. gondii seropositive patients was 1.63 (95% CI 1.01 to 2.66), p = 0.048; the adjusted odds ratio was 1.95 (95% CI 1.15 to 3.30), p = 0.014. Plasma KYN was not associated with a history of NF-SSDV in T. gondii seronegative patients. The results suggest that T. gondii and KYN may have a nonlinear cumulative effect on the risk of NF-SSDV among those with schizophrenia. If confirmed by future longitudinal studies, this result is expected to have both theoretical and clinical implications for the prevention and treatment of suicidal behavior.
authors.affiliation: Department of Psychiatry, University of Maryland-Baltimore School of Medicine, Baltimore, MD, USA; Department of Psychiatry and Behavioral Sciences, University of Texas Health Science Center at Houston, Houston, TX, USA.
authors.forename: Olaoluwa
authors.initials: O
authors.lastname: Okusaga
authors.affiliation: Mental Health Service, Atlanta Veterans Affairs Medical Center and Emory University, School of Medicine, Department of Psychiatry and Behavioral Sciences, Atlanta, GA, USA.
authors.forename: Erica
authors.initials: E
authors.lastname: Duncan
authors.affiliation: Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, MD, USA.
authors.forename: Patricia
authors.initials: P
authors.lastname: Langenberg
authors.affiliation: Division of Psychiatry and Behavioral Medicine, College of Human Medicine, Michigan State University and the Van Andel Research Institute, Grand Rapids, MI, USA.
authors.forename: Lena
authors.initials: L
authors.lastname: Brundin
authors.affiliation: Division of Biological Chemistry, Biocenter, Innsbruck Medical University, Innsbruck, Austria.
authors.forename: Dietmar
authors.initials: D
authors.lastname: Fuchs
authors.affiliation: University of South Florida, Tampa, FL, USA.
authors.forename: Maureen W
authors.initials: MW
authors.lastname: Groer
authors.affiliation: Department of Psychiatry, Martin-Luther-University Halle-Wittenberg, Halle, Germany.
authors.forename: Ina
authors.initials: I
authors.lastname: Giegling
authors.affiliation: Rocky Mountain Mental Illness Research Education and Clinical Center (MIRECC), Denver, CO, USA; Military and Veteran Microbiome Consortium of Research and Education (MVM CORE), Denver, CO, USA.
authors.forename: Kelly A
authors.initials: KA
authors.lastname: Stearns-Yoder
authors.affiliation: Department of Psychiatry, Martin-Luther-University Halle-Wittenberg, Halle, Germany.
authors.forename: Annette M
authors.initials: AM
authors.lastname: Hartmann
authors.affiliation: Department of Psychiatry, Martin-Luther-University Halle-Wittenberg, Halle, Germany.
authors.forename: Bettina
authors.initials: B
authors.lastname: Konte
authors.affiliation: Department of Psychiatry, Martin-Luther-University Halle-Wittenberg, Halle, Germany.
authors.forename: Marion
authors.initials: M
authors.lastname: Friedl
authors.affiliation: Rocky Mountain Mental Illness Research Education and Clinical Center (MIRECC), Denver, CO, USA; Military and Veteran Microbiome Consortium of Research and Education (MVM CORE), Denver, CO, USA; Department of Psychiatry, University of Colorado, Anschutz Medical Campus, Aurora, CO, USA; Department of Neurology, University of Colorado, Anschutz Medical Campus, Aurora, CO, USA; Department of Physical Medicine and Rehabilitation, University of Colorado, Anschutz Medical Campus, Aurora, CO, USA.
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Brenner
authors.affiliation: Military and Veteran Microbiome Consortium of Research and Education (MVM CORE), Denver, CO, USA; Department of Integrative Physiology and Center for Neuroscience, University of Colorado Boulder, Boulder, CO, USA.
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Lowry
authors.affiliation: Department of Psychiatry, Martin-Luther-University Halle-Wittenberg, Halle, Germany.
authors.forename: Dan
authors.initials: D
authors.lastname: Rujescu
authors.affiliation: Department of Psychiatry, University of Maryland-Baltimore School of Medicine, Baltimore, MD, USA; Rocky Mountain Mental Illness Research Education and Clinical Center (MIRECC), Denver, CO, USA; Military and Veteran Microbiome Consortium of Research and Education (MVM CORE), Denver, CO, USA; Veterans Integrated Service Network (VISN) 5, Mental Illness Research Education and Clinical Center (MIRECC), Baltimore, MD, USA. Electronic address: tpostolache@psych.umaryland.edu.
authors.forename: Teodor T
authors.initials: TT
authors.lastname: Postolache
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007737:Kynurenine / Q000097:blood*; D008297:Male; D016017:Odds Ratio; D012559:Schizophrenia / Q000097:blood* / Q000150:complications* / Q000453:epidemiology; D016728:Self-Injurious Behavior / Q000097:blood / Q000150:complications / Q000453:epidemiology; D013406:Suicide, Attempted / Q000706:statistics & numerical data*; D014123:Toxoplasmosis / Q000097:blood* / Q000150:complications* / Q000453:epidemiology
chemical_list: D007737:Kynurenine
keywords: Kynurenine; Non-fatal suicidal self-directed violence; Schizophrenia; Toxoplasma gondii