Psychobiological functioning in mid-adolescent girls and boys Linkages to self reported stress, self-esteem and recurrent pain

Abstract: Among adolescents, the day-to-day functioning of the hypothalamo-pituitary-adrenal-axis (HPA-axis) and of the autonomic nervous system (ANS) and their relationships with stress, subjective health complaints and psychological factors such as self-esteem, studied in naturalistic settings, have been largely unexplored. This thesis aimed to investigate the diurnal activity of the HPA-axis (Studies I & II) in terms of salivary cortisol and the ANS/SNS system (Study III) in terms of salivary alpha-amylase (sAA) in mid-adolescent girls and boys. Additionally, linkages between self-reported stress, self-esteem, recurrent pain and biomarkers were investigated. A further aim was to describe potential differences between girls and boys respectively. Study I showed that both girls and boys exhibited the typical diurnal cortisol profile with high levels in the morning that decreased throughout the day. Girls had higher total cortisol levels, while no differences emerged for measures of the cortisol increase. Study II showed no significant linkages between self-ratings of stress and cortisol. However, stress was associated with recurrent pain in girls. Study III showed that, for girls, both self-esteem and self-reported stress were related to morning levels of both cortisol and sAA, to the diurnal sAA output and to a conjoint measure of amylase over cortisol, AOC. To conclude, the findings suggest that both stress and self-esteem may be linked to different measures of ANS and HPA-axis activity, but also to measures of ANS and HPA-axis dysregulation, particularly among mid-adolescent girls.