Biochemical Assessment of Circadian Processes in ASD

Background: The pineal hormone melatonin (MEL) is secreted with a marked day-night rhythm and it plays a crucial role in circadian rhythms. MEL also has powerful antioxidant properties. Studies in school-age children, adolescents and young adults have reported lower group mean production of melatonin in ASD.

Objectives: We wished to examine daytime and nighttime production of MEL, as well as other diurnally varying neurohormones, in younger ASD and typically developing individuals in order to understand better this apparent deficit and to assess the potential utility of the measure in screening.

Methods: Melatonin sulfate, norepinephrine, epinephrine, cortisol and creatinine were measured in methanolic extracts of daytime and overnight diapers obtained from toddlers ages 18-36 months. ASD subjects received an extensive behavioral assessment and caregivers completed a questionnaire asking about sleep and gastrointestinal related behaviors and problems.

Results: Diapers have been obtained from 53 typically individuals and a similar number of ASD subjects. Analysis of diaper extracts for the neurohormones has been successful and data analysis is ongoing.

Conclusions: Collection and extraction of daytime and overnight diapers obtained from toddlers with ASD provides a feasible approach to the study of circadian rhythms in younger individuals with ASD. The completed data analysis will indicate whether lower production of melatonin is also found in younger individuals with ASD and will examine the specifity of potential alterations in diurnally vary neurohormones.