Moderation of the relationship between Toxoplasma gondii seropositivity and trait impulsivity in younger men by the phenylalanine-tyrosine ratio

Peng, Xiaoqing; Brenner, Lisa A.; Mathai, Ashwin J.; Cook, Thomas; Fuchs, Dietmar; Postolache, Nadine; Groër, Maureen; Pandey, Janardan P.; Mohyuddin, Farooq; Giegling, Ina; Wadhawan, Abhishek; Hartmann, Annette M.; Konte, Bettina; Brundin, Lena; Friedl, Marion; Stiller, John W.; Lowry, Christopher A.; Rujescu, Dan; Postolache, Teodor T.

doi:10.1016/j.psychres.2018.03.045

Cited by 9 publications

(12 citation statements)

References 156 publications

(206 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…To this end, T. gondii infection is thought to trigger an immune response in the brain that could lead to decreased tryptophan availability, decreased serotonin biosynthesis, and increased levels of kynurenic acid 196,197 . Of note, T. gondii infection may also amplify specific behavioural traits that are linked with suicidal behaviour, such as aggression in women and impulsivity in men 198,199 .…”

Section: [H2] Neurobiology Of Suicidal Behaviourmentioning

confidence: 99%

Suicide and suicide risk

Turecki

Brent²,

Gunnell

et al. 2019

Nat Rev Dis Primers

619

473

View full text Add to dashboard Cite

Although recent years have seen large decreases in the overall global rate of suicide fatalities, this trend is not reflected everywhere. Suicide and suicidal behaviour continue to present key challenges for public policy and health services, with increasing suicide deaths in some countries, such as the USA. The development of suicide risk is complex, involving contributions from biological (including genetics), psychological (such as certain personality traits), clinical (comorbid psychiatric illness), social and environmental factors. The involvement of multiple risk factors in conveying risk of suicide means that determining an individual's risk of suicide is challenging. Improving risk assessment, for example using computer testing and genetic screening, is an area of ongoing research. Prevention is key to reduce the number of suicide deaths, and current efforts include universal, selective and indicated interventions, although these interventions are often delivered in combination. These interventions, combined with psychological (such as cognitive behavioural therapy, caring contacts and safety planning) and pharmacological treatments (for example, clozapine and ketamine) and coordinated social and public health initiatives, should continue to improve the management of suicidal patients and decrease suicide-associated morbidity. [H1] Epidemiology Based on self-report survey data, the WHO has estimated that for every death by suicide ~20 people make suicide attempts 1. This ratio varies from country to country depending on the lethality of commonly used suicide methods. In all countries, the incidence of suicide attempts is highest in individuals 15-24 years of age. By comparison, the lowest rates of suicide is observed amongst young people <15 years of age, with the highest generally observed in people >75 years of age 1. However, the age-groups with the highest incidence at other ages vary from region to region; for example, in a 25

show abstract

Section: [H2] Neurobiology Of Suicidal Behaviourmentioning

confidence: 99%

Suicide and suicide risk

Turecki

Brent²,

Gunnell

et al. 2019

Nat Rev Dis Primers

619

473

View full text Add to dashboard Cite

show abstract

“…testosterone) and neurotransmitters (e.g. serotonin, dopamine and norepinephrine) have been explored [23]. Increases in testosterone, for instance, which have been linked to T. gondii infection [24], can enhance risk-taking behaviour, aggression and impulsivity in humans [17,25].…”

Section: Introductionmentioning

confidence: 99%

Risky business: linkingToxoplasma gondiiinfection and entrepreneurship behaviours across individuals and countries

et al. 2018

View full text Add to dashboard Cite

Disciplines such as business and economics often rely on the assumption of rationality when explaining complex human behaviours. However, growing evidence suggests that behaviour may concurrently be influenced by infectious microorganisms. The protozoan infects an estimated 2 billion people worldwide and has been linked to behavioural alterations in humans and other vertebrates. Here we integrate primary data from college students and business professionals with national-level information on cultural attitudes towards business to test the hypothesis that infection influences individual- as well as societal-scale entrepreneurship activities. Using a saliva-based assay, we found that students ( = 1495) who tested IgG positive for exposure were 1.4× more likely to major in business and 1.7× more likely to have an emphasis in 'management and entrepreneurship' over other business-related emphases. Among professionals attending entrepreneurship events,-positive individuals were 1.8× more likely to have started their own business compared with other attendees ( = 197). Finally, after synthesizing and combining country-level databases on infection from the past 25 years with the Global Entrepreneurship Monitor of entrepreneurial activity, we found that infection prevalence was a consistent, positive predictor of entrepreneurial activity and intentions at the national scale, regardless of whether previously identified economic covariates were included. Nations with higher infection also had a lower fraction of respondents citing 'fear of failure' in inhibiting new business ventures. While correlational, these results highlight the linkage between parasitic infection and complex human behaviours, including those relevant to business, entrepreneurship and economic productivity.

show abstract

“…A high phenylalanine:tyrosine ratio, resulting from inhibition of phenylalanine hydroxylase [67,68], can be the consequence of Th1 activation, one of the central immune mechanisms responsible for containing T. gondii infection in immunocompetent hosts [69]. We recently reported how associations between T. gondii and aggression [70] or impulsivity [71], known to be in part modulated by dopaminergic pathways, interact with plasma peripheral levels of phenylalanine:tyrosine ratios. Independent of dopaminergic mechanisms, as any microbial organism, T. gondii can promote sleep through the induction of the immune system.…”

Section: Discussionmentioning

confidence: 99%

Toxoplasma gondii IgG associations with sleepwake problems, sleep duration and timing

et al. 2019

Self Cite

View full text Add to dashboard Cite

Background: Evidence links Toxoplasma gondii (T. gondii), a neurotropic parasite, with schizophrenia, mood disorders and suicidal behavior, all of which are associated and exacerbated by disrupted sleep. Moreover, low-grade immune activation and dopaminergic overstimulation, which are consequences of T. gondii infection, could alter sleep patterns and duration. Methods: Sleep data on 833 Amish participants [mean age (SD) = 44.28 (16.99) years; 59.06% women] were obtained via self-reported questionnaires that assessed sleep problems, duration and timing. T. gondii IgG was measured with ELISA. Data were analyzed using multivariable logistic regressions and linear mixed models, with adjustment for age, sex and family structure. Results: T. gondii seropositives reported less sleep problems (p < 0.005) and less daytime problems due to poor sleep (p < 0.005). Higher T. gondii titers were associated with longer sleep duration (p < 0.05), earlier bedtime (p < 0.005) and earlier mid-sleep time (p < 0.05). Conclusions: It seems unlikely that sleep mediates the previously reported associations between T. gondii and mental illness. Future longitudinal studies with objective measures are necessary to replicate our findings.

show abstract

Moderation of the relationship between Toxoplasma gondii seropositivity and trait impulsivity in younger men by the phenylalanine-tyrosine ratio

Cited by 9 publications

References 156 publications

Suicide and suicide risk

Suicide and suicide risk

Risky business: linkingToxoplasma gondiiinfection and entrepreneurship behaviours across individuals and countries

Toxoplasma gondii IgG associations with sleepwake problems, sleep duration and timing

Contact Info

Product

Resources

About