Salivary Cortisol Levels and Diurnal Patterns in Children with Autism Spectrum Disorder

Autism spectrum disorder (ASD) is characterized by significant heterogeneity in functional levels that can reportedly affect stress. This study examined the diurnal patterns and cortisol levels of low-functioning children with ASD, high-functioning children with ASD, and typically-developing children between the ages of 7 and 12 years. Saliva was collected from each participant three times per day (AM, noon, and PM) during two consecutive weekends. Results indicated that all three groups demonstrated the typical diurnal pattern (highest cortisol at AM, followed by noon, and lowest at PM). Although results revealed no significant group x time interaction, significant main effects were found for time and group. These effects indicated that collectively, all three groups demonstrated mean differences in cortisol levels across the day. In addition, the low-functioning ASD group yielded significantly higher mean cortisol levels than the high-functioning ASD and typically-developing groups; the high-functioning ASD and typically-developing groups did not significantly differ.