Exposure to common infections and risk of suicide and self-harm: a longitudinal general population study

Abstract

Common infectious agents, such as Toxoplasma gondii (T. gondii) and several human herpes viruses, have been linked to increased risk of self-harm. The aim of this study was to investigate the associations between self-harm and seropositivity to T. gondii, Epstein-Barr virus (EBV), Herpes Simplex virus Type 1 (HSV-1), and Cytomegalovirus (CMV). IgM and IgG antibodies to these infections were measured in the Health 2000 project nationally representative of the whole Finnish adult population, and 6250 participants, age 30 and over, were followed for 15 years via registers. In addition, lifetime suicidal ideation and suicide attempts based on medical records and interview were assessed within a subsample of 694 participants screened to a substudy for possible psychotic symptoms or as controls. Among the 6250 participants, 14 individuals died of suicide and an additional 4 individuals had a diagnosis of intentional self-harm during follow-up. Serological evidence of lifetime or acute infections was not found to be associated with these suicidal outcomes. However, in the subsample, those seropositive for CMV had fewer suicide attempts compared to those seronegative, adjusting for gender, age, educational level, childhood family size, regional residence, CRP, and screen status (OR for multiple attempts = 0.40, 95% confidence interval 0.20-0.83, p = 0.014). To conclude, common infections were not associated with risk of death by suicide or with self-harm diagnoses at a 15-year follow-up in the general population sample. Our finding of an increased number of suicide attempts among persons seronegative for CMV calls for further research.

Prevalence and Predictors of Toxoplasma gondii Infection in Psychiatric Inpatients in Fars Province, Southern Iran

“…The highlighted inflammatory pathways and associated chemical compounds affecting the nervous system can play key roles in behavioral development that triggers suicide attempts ( 64 , 65 ). In contrast, the current results deny associations between T. gondii infection and suicidal attempts discovered in a study on patients suffering from mental and behavioral disorders due to psychoactive substance use in Mexico ( 66 ), adolescents in Turkey ( 67 ) and general population study in Finland ( 68 ). Further studies with a wide range of sociodemographic, clinical and behavioral variables are necessary to investigate associations between T. gondii infection and suicide attempts.…”

Association between Suicide and Toxoplasma gondii Seropositivity

“…In contrast, our results agree with a lack of association between T. gondii exposure and suicidal ideation found in a study of patients suffering from mental and behavioral disorders due to psychoactive substance use in Mexico [ 22 ], and a lack of association between T. gondii seropositivity and suicide attempts in adolescents in Turkey [ 23 ]. In addition, in a longitudinal general population study in Finland, suicidal outcomes were not associated with T. gondii seropositivity [ 24 ]. The negative result found in the present study does not indicate that there is not any association between T. gondii infection and completed suicide.…”

Raised C-reactive protein in medication overdose: A report of two cases

“…Another study assessed the role of common infections on suicidality and revealed that common infections have no influential role on suicide and suicidal behavior. 10 However, the role of inflammation and increased level of CRP has been noted in an other study. 11 It has been postulated that chronic inflammatory response could have roles in influencing the suicidal behavior.…”