What worries parents of a child with Autism? Evidence from a biomarker for chronic stress.

Bitsika et al. (2017) asked 149 parents of kids with autism to spit into tubes at waking, noon, and bedtime for three days. They measured cortisol, a stress hormone, to see if daily rhythms were off. Parents also filled out forms about their child’s sleep, tantrums, and self-injury.

The team wanted to know which child behaviors, if any, broke the parents’ stress cycle.

Only one thing mattered: when the child hit, bit, or banged their own body, the parent’s cortisol rhythm flattened. Other tough behaviors—sleep loss, tantrums, picky eating—did not show the same link.

In plain words, self-injury is the single clearest signal that Mom or Dad is living in chronic stress.

Mukherjee et al. (2021) found the same pattern in kids’ hair: severe self-injury raised cortisol there too. Together the papers show the same stress signal in two bodies—child and parent.

Bravo Balsa et al. (2024) looked at autistic teens and saw higher total daily cortisol plus flatter slopes when social struggles were high. Their data extend Vicki’s work from parents to the youth themselves, suggesting the whole family runs on a stressed clock.

Edmiston et al. (2017) seems to disagree at first: autistic teens showed almost NO cortisol jump during a lab stress test. The key difference is timing—Kale captured a short, social stress shot while Vicki tracked slow, everyday wear-down. Both can be true: the teen’s body under-reacts to a stranger, yet the parent’s body stays stuck on high at home.

If you serve families with autism, treat severe self-injury as a two-person crisis. Teaching replacement skills to the child is also medical care for the parent. Add quick cortisol checks—saliva kits are cheap—and you can show families objective proof that behavior plans lower stress for everyone.