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

OBJECTIVES: 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. METHOD: 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. RESULTS: 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. CONCLUSION: 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.

Pre-schoolers suffering from psychiatric disorders show increased cortisol secretion and poor sleep compared to healthy controls.

BACKGROUND: Various studies of child cortisol secretion and sleep show a close association between poor sleep, deterioration of the HPA axis and unfavorable psychological functioning. However, there is little evidence as to whether these associations are clearly present in pre-school children suffering from psychiatric disorders. METHOD: A total of 30 pre-schoolers suffering from psychiatric disorders (anxiety, adjustment disorders, emotional and attachment disorder; hyperactivity or oppositional disorder) and 35 healthy controls took part in the study. Saliva cortisol secretion was assessed both at baseline and under challenge conditions. Sleep was assessed via activity monitoring for seven consecutive days and nights, using a digital movement-measuring instrument. Parents and teachers completed questionnaires assessing children's cognitive, emotional and social functioning. The Berkeley Puppet Interview provided child-based reports of cognitive-emotional processes. RESULTS: Compared to healthy controls, children suffering from psychiatric disorders had much higher cortisol secretion both at baseline and under challenge conditions. Sleep was also more disturbed, and parents and teachers rated children suffering from psychiatric disorders as cognitively, emotionally and behaviorally more impaired, relative to healthy controls. Children with psychiatric disorders reported being more bullied and victimized. CONCLUSIONS: In five-year old children the presence of psychiatric disorders is reflected not only at psychological, social and behavioral, but also at neuroendocrine and sleep-related levels. It is likely that these children remain at increased risk for suffering from psychiatric difficulties later in life.