In pre-school children, cortisol secretion remains stable over 12 months and is related to psychological functioning and gender

Cross-sectional studies provide evidence that cortisol secretion as a marker of hypothalamus-pituitary-adrenocortical axis activity (HPA AA) is related to psychological functioning and behavior. However, there are no studies of the stability of the HPA AA in pre-schoolers over the longer term. The aim of the present study was therefore to investigate cortisol secretion in pre-schoolers longitudinally, and to predict psychological functioning 12 months later.; 92 pre-schoolers (mean age: 5.4 years; 44% females) took part in a follow-up assessment 12 months after initial assessment. Cortisol secretion was assessed both at baseline (morning cortisol secretion) and under challenge conditions, and a thorough psychological assessment was included.; Increased cortisol secretion at 5.4 years predicted increased cortisol secretion and psychological difficulties at 6.4 years. Compared to boys, girls had higher cortisol secretion at both 5.4 and 6.4 years. Cross-sectionally, at the age of 6.4 years, levels of cortisol secretion impacted differentially on girls' and boys' behavior.; In pre-schoolers, HPA axis activity at 5.4 years is stable over the following 12 months and is associated with psychological functioning. Pre-schoolers with higher cortisol levels are at increased risk of developing further psychological difficulties. Gender affects the manner in which HPA axis activity impacts on psychological functioning. Moreover, gender differences in cortisol secretion occur already in prepubertal children and appear to be independent from sex steroids.