Toxoplasma gondii infection seropositivity not associated with increased violent behaviour in inmates

1. In this cross-sectional study, T. gondii seropositivity was not associated with increased violent behaviour when compared with T. gondii seronegative participants in a sample of Mexican inmates.

Evidence Rating Level: 2 (Good)

Toxoplasma gondii (T. gondii) is a protozoan parasite that causes infections worldwide; an estimated one-third of humanity has been exposed to this parasite. T. gondii infection is typically associated with cervical lymphadenopathy or ocular disease and can cause blindness and mental retardation in congenitally affected children. In its latent form, T. gondii resides in the central nervous system and drastically alters the behaviour of rodents and is associated with mental disorders such as obsessive-compulsive disorder, schizophrenia, generalized anxiety disorder, bipolar depression, and disorder. Currently, there is a paucity of research regarding the association between T. gondii infection and violent behaviour. This cross-sectional study aimed to investigate the association between T. gondii seropositivity and violent behaviour in a sample of inmates from the Mexican city of Durango.  In total, 128 participants were enrolled from a state correctional facility in Durango, including 112 males and 16 females. Participants were tested for anti-T. gondii IgG antibodies and had their risk of violence assessed using multiple scoring tools including the Historical, Clinical, and Risk Management-20 (HCR-20), the assessment of aggression by the Buss-Perry aggression questionnaire (AGQ), and analysis of their crimes. Anti-T. gondii IgG antibodies were found in 6 (4.7%) of the 128 inmates studied. Regarding the risk of violence, 113 (88.3%) of inmates were considered violent in at least one of the evaluations, 50 (39.1%) in at least 2 evaluations, and 4 (3.1%) in all three evaluations. There was no statistically significant difference in anti-T. gondii IgG seroprevalence when comparing violent and non-violent inmates, which was persistent whether the inmates were considered violent in at least one, two, or three evaluations. For example, the mean scores of the AGQ in T. gondii seropositive inmates (73.67 ± 29.09; 95% CI: 50.00–99.31) were similar to those (79.84 ± 25.00; 95% CI: 75.46–84.27) found in T. gondii seronegative inmates (P = 0.55). Further stratification by type of aggression did not reveal any statistically significant differences between the T. gondii seropositive inmates and the T. gondii seronegative inmates. Overall, the findings from this study suggest that T. gondii seropositivity is not associated with violent behaviour in inmates. A major limitation of this study is its small sample size, which may increase the probability of type II error. This study acts as an important step to understanding the effects of T. gondii seropositivity on behaviour, and further research with larger sample sizes is essential to corroborate the findings from this study.

Click to read the study in PLOS

Image: PD

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