Can reactivity to stress and family environment explain memory and executive function performance in early and middle childhood?

INTRODUCTION: According to the literature, children's overall reactivity to stress is associated with their socioeconomic status and family environment. In turn, it has been shown that reactivity to stress is associated with cognitive performance. However, few studies have systematically tested these three constructs together.
OBJECTIVE: To investigate the relationship between family environment, salivary cortisol measurements and children's memory and executive function performance.
METHOD: Salivary cortisol levels of 70 children aged 9 or 10 years were measured before and after performing tasks designed to assess memory and executive functions. Questionnaires on socioeconomic issues, family environment and maternal psychopathologies were administered to participants' families during the children's early childhood and again when they reached school age.
RESULTS: Data were analyzed by calculating correlations between variables and conducting hierarchical regression. High cortisol levels were associated with poorer working memory and worse performance in tasks involving executive functions, and were also associated with high scores for maternal psychopathology (during early childhood and school age) and family dysfunction. Family environment variables and changes in cortisol levels explain around 20% of the variance in performance of cognitive tasks.
CONCLUSION: Family functioning and maternal psychopathology in early and middle childhood and children's stress levels were associated with children's working memory and executive functioning.