Citation

Okusaga O, Duncan E, Langenberg P, Brundin L, Fuchs D, Groer MW, Giegling I, Stearns-Yoder KA, Hartmann AM, Konte B, Friedl M, Brenner LA, Lowry CA, Rujescu D, Postolache TT. J. Psychiatr. Res. 2015; 72: 74-81.

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.

Copyright

(Copyright © 2015, Elsevier Publishing)

DOI

10.1016/j.jpsychires.2015.10.002

PMID

26594873

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.

Language: en