The relationship between childhood autistic traits and diurnal cortisol activity in adolescence

Autistic adolescents experience higher levels of stress compared to non-autistic adolescents. Chronic stress is associated with dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis, which can be measured by cortisol levels. Previous studies investigating cortisol activity in autistic adolescents are predominantly cross-sectional, have small sample sizes, exclude females, and include those with a clinical diagnosis of autism. The currently study sought to prospectively examine whether the severity and persistence of autistic traits in childhood is associated with cortisol activity in adolescence in a population-representative cohort.

Data from 915 participants from the Avon Longitudinal Study of Parents and Children (ALSPAC) were used. Bivariate correlations were calculated between autistic traits (using the Social Communication Disorders Checklist) at ages 8, 11 and 14 years and four cortisol activity indices at age 15 years (diurnal cortisol slope, cortisol awakening response (CAR), total morning cortisol, and daily total cortisol output). Regression analyses investigated the effect of autistic traits on cortisol activity, before and after adjustment for confounders.

Being likely autistic (i.e., demonstrating severe and persistent autistic traits across ages 8-14 years) was associated with increased CAR, even after adjustment for confounders. No associations were observed between autistic traits and diurnal cortisol slope, total morning cortisol, or total daily cortisol output.

The observation that autistic traits are associated with CAR, but not other cortisol activity indicators, suggests this may not reflect a generalised HPA axis dysfunction in autistic youth, but a heightened situational response during periods of transition and increased anticipatory stress.