Recording Stress Biomarkers in Autism Spectrum Disorders

The goal of this observational study is to learn how stress affects children and young people with autism spectrum disorder (ASD). Many individuals with autism experience strong stress reactions that may lead to challenging behaviours such as agitation, withdrawal, aggression, or self-injury. These behaviours can be difficult to predict, especially in people who have limited communication abilities.

Researchers want to better understand how the body reacts to stress in real-life situations. The study focuses on two main biological systems involved in the stress response:

the autonomic nervous system, which produces fast reactions such as changes in heart rate and sweating, and the hypothalamic-pituitary-adrenal axis, which produces slower hormonal responses such as cortisol.

The main questions the study aims to answer are:

* Do physiological stress signals differ between individuals with ASD and those without ASD? * Are there differences in physiological stress responses between individuals with ASD and non-ASD participants? * Can physiological markers help identify stress earlier in people with autism?

Researchers will compare children and young people with autism to a control group of participants without autism to see whether their stress responses differ.

Participants will take part in monitoring during their normal daily activities. This allows researchers to observe stress responses in natural environments such as school, home, or specialized care institutions.

Participants will:

* Wear a wrist device during the day that measures heart rate, heart rate variability, skin conductance, skin temperature, and movement * Provide saliva samples in the morning and afternoon to measure stress hormones such as cortisol and alpha-amylase * Have additional saliva samples collected after behavioural crises or stressful events when possible * Be observed by a trained researcher who records behavioural events and the surrounding context

Researchers will combine physiological data, behavioural observations, and contextual information such as physical activity, environmental conditions, and daily routines. This will help identify patterns of stress in everyday life.

The results of this study may help researchers better understand the physiology of stress in autism and support the future development of wearable systems that could detect stress early and help prevent behavioural crises.