To Örebro University

AIMS: Hypothalamic-pituitary-adrenal (HPA) axis activity may prove a viable biomarker for identifying those susceptible to alcohol use disorders. The purpose of this study was to examine the relation of the age at which adolescents begin drinking with diurnal and stress cortisol.

DESIGN: Adolescents' diurnal cortisol levels on a normal day and cortisol levels during a stress procedure were examined in relation to the age of onset of alcohol use.

SETTING AND PARTICIPANTS: All adolescents (aged 14-20 years) were part of a general population study in the Netherlands (n = 2286).

MEASUREMENTS: Ten assessments of salivary cortisol taken on a normal day (diurnal cortisol), as well as during a social stress procedure (stress cortisol) were used as indicators of HPA axis activity.

FINDINGS: The age at which the first alcoholic drink was consumed varied as a function of cortisol levels at the onset of as well as during the stress procedure. Those who began drinking at an earlier age showed lower cortisol levels at the onset of the stressful tasks (r(2) = 0.14, P < 0.001) and during the stressful tasks (r(2) = 0.10, P < 0.05), although not after the tasks (cortisol recovery). Effects were strongest for anticipatory pre-task cortisol levels. Differences in diurnal cortisol levels did not explain variance in the age at which adolescents had begun drinking.

CONCLUSIONS: Lessened activity of the hypothalamic-pituitary-adrenal axis at the onset of and during a stress procedure is present in adolescents who begin drinking at an early age.