Lower cortisol and higher ACTH levels in individuals with autism.

Curin et al. (2003) drew blood from autistic and non-autistic people. They checked two stress hormones: cortisol and ACTH.

The team wanted to know if the body’s main stress system, the HPA-axis, works differently in autism.

Autistic participants had lower cortisol and higher ACTH than controls. This mismatch hints the HPA-axis is dysregulated.

In plain words, their stress engine is idling at the wrong speed.

Bozkurt et al. (2021) and Bravo Balsa et al. (2024) saw the opposite: autistic kids or teens had higher cortisol, not lower. The clash is only on the surface. Marinović sampled mixed ages in 2003; the newer papers focused on children or teens, showing cortisol changes with age.

Greene et al. (2019) and Edmiston et al. (2017) extend the story. They found blunted evening or stress-challenge cortisol in autistic adults and adolescents, backing the idea of broad HPA-axis hypo-activity.

Johnson et al. (2009) add nuance: some autistic kids run high, some run low. Individual profiles matter more than a single “autistic” level.

You can’t judge stress in autism by eye. Low cortisol today might flip to high next year, and either can signal HPA dysregulation. Track cortisol only when it guides treatment—like before starting a sleep intervention or assessing chronic self-injury. Always compare against the person’s past values, not just norms.