Anja C. Huizink

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 (r² = 0.14, P < 0.001) and during the stressful tasks (r² = 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.

Aims  To investigate the relationship of life‐time and repeated cannabis use with hypothalamic–pituitary–adrenal (HPA) axis reactivity to social stress in a general population sample of adolescents.Design  Adolescents who reported life‐time or repeated cannabis use, life‐time or repeated tobacco use and never use of either cannabis or tobacco were compared with respect to their HPA axis reactivity during the Groningen Social Stress Task (GSST), which was based on the Trier Social Stress Task.Setting  A large prospective population study of Dutch adolescents [the TRacking Adolescents' Individual Lives Survey (TRAILS) study].Participants  A total of 591 adolescents (51% male) who participated in the GSST, which was an additional measurement during the third assessment wave.Measurements  HPA axis stress‐reactivity was indexed by four cortisol samples collected before, during and after the GSST. Furthermore, all adolescents in our study completed self‐reported questionnaires on life‐time and repeated cannabis and tobacco use. Models were adjusted for sex, recent alcohol use, experimental session risk status, socio‐economic status, mood and time of the experimental session.Findings  Life‐time cannabis users had significantly lower stress‐reactivity levels when compared to abstainers [odds ratio (OR) = 0.68, confidence interval (CI) = 0.55–0.85, P < 0.01] and life‐time tobacco users (OR = 0.79, CI = 0.64–0.98, P < 0.05). In addition, repeated cannabis users also exhibited lower stress‐reactivity levels when compared to life‐time ever users of either tobacco or cannabis (OR = 0.74, CI = 0.53–0.98, P < 0.05).Conclusions  Lower hypothalamic–pituitary–adrenal‐axis stress‐reactivity in adolescents is related specifically to life‐time and repeated cannabis use.

Objective:Among Finnish adolescent twins, we compared (a) a model that describes a direct impact of liability to tobacco use on cannabis and other illicit drug use with (b) a model that included a ...