Toxoplasma gondii infection in people with schizophrenia is related to higher hair glucocorticoid levels.

Introduction: Toxoplasma gondii (TG) is a common protozoan parasite infecting approximately one third of the human population. Animal studies have shown that this parasite can manipulate its host behavior. Based on this, human studies have assessed if TG can be involved in mental health disorders associated with important behavioral modifications such as schizophrenia. However, results have been discrepant. Given that TG has a strong impact on fear and risk-taking processes in animal studies and that fear and risk-taking behaviors are associated with the human stress response, we tested whether glucocorticoid biomarkers (salivary and hair) differ in people with schizophrenia and controls as a function of TG status. Methods: We measured TG antibodies in blood samples, as well as salivary and hair glucocorticoid levels in 226 people with schizophrenia (19.9% women, mean age = 39 years old) and 129 healthy individuals (controls) (45.7% women, mean age = 41 years old). Results: The results showed that people with schizophrenia infected with TG presented significantly higher hair glucocorticoid concentrations than non-infected people with schizophrenia. This effect was not found in control participants. No effect was observed for salivary glucocorticoid levels. Additionally, there were no associations between TG infection and positive psychotic symptoms nor impulsivity. Discussion: These results show that people with schizophrenia present high levels of hair glucocorticoid levels only when they are infected with TG. Further studies performed in populations suffering from other mental health disorders are needed to determine if this effect is specific to schizophrenia, or whether it is generalized across mental health disorders.

Stress, anxiety, emotion regulation and social support in parent-child dyads prior to and during the onset of the COVID-19 pandemic.

In March 2020, and in order to assess the impact of the COVID-19 pandemic on stress and mental health in parent-child dyads using pre-pandemic measures, we recontacted participants from a 2019 study. A total of 136 dyads of Canadian parents (77% mothers, mean age = 44.48 years/old) and children (63% girls, 77% aged 10-12 years/old and 23% aged 15-17 years/old) completed self-report measures of perceived stress, anxiety (state/sensitivity) and emotion regulation strategies (cognitive reappraisal/expressive suppression). Children additionally completed measures of co-rumination and perceived social support from friends, parents, and teachers. Results revealed a significant increase in parents' stress and state anxiety during the pandemic compared to before, but not in their children. Dyads' anxiety sensitivity remained unchanged, as well as parents' use of cognitive reappraisal and expressive suppression. Children showed similar use of cognitive reappraisal, but less expressive suppression and co-rumination during the pandemic compared to before. Children reported similar perceived social support from all sources over time. Finally, parental and children scores were not significantly correlated at either time. These results suggest that during the onset of the COVID-19 pandemic, parents and children responded differently in terms of stress, anxiety, and emotion regulation strategies.