Assessment & Research

Associations Among Diurnal Salivary Cortisol Patterns, Medication Use, and Behavioral Phenotype Features in a Community Sample of Rett Syndrome.

Byiers et al. (2020) · American journal on intellectual and developmental disabilities 2020
★ The Verdict

In Rett syndrome, salivary cortisol patterns vary with mutation severity and anticonvulsant use—consider these factors when assessing stress physiology.

✓ Read this if BCBAs serving girls with Rett syndrome in home or clinic programs.
✗ Skip if Practitioners who only treat typically developing clients.

01Research in Context

01

What this study did

Anthony et al. (2020) tracked spit-cortisol across one day in thirty girls with Rett syndrome.

They asked: does the gene-mutation type, seizure drug use, or teeth-grinding change the daily cortisol slope?

Each family collected saliva at wake, noon, and bedtime at home.

02

What they found

Girls with more severe gene mutations had flatter, less healthy cortisol slopes.

Those on anticonvulsants and those who grind their teeth showed the same dampened pattern.

The results flag a stressed stress-system in RTT.

03

How this fits with other research

Prigge et al. (2013) first saw blunted morning cortisol in adults with ID; J’s RTT data now show the same flat line in girls, linking ID and RTT under one HPA-axis story.

Sánchez-Luquez et al. (2025) used hair cortisol in teens with ID and also found high chronic stress, stretching the RTT saliva finding into a longer time window.

Thapa et al. (2021) saw that psychotropic meds lower heart-rate variability in ASD; J saw that anticonvulsants flatten cortisol in RTT—both papers warn that common pills tweak stress physiology.

04

Why it matters

When you assess a girl with RTT, note her mutation, seizure drug list, and bruxism. These three signs predict a tired HPA-axis. A flat cortisol slope may explain irritability or sleep issues. Share the spit-test results with the neurologist before tweaking meds, and consider stress-lowering routines like massage or quiet bedtime rituals.

Free CEUs

Want CEUs on This Topic?

The ABA Clubhouse has 60+ free CEUs — live every Wednesday. Ethics, supervision & clinical topics.

Join Free →
→ Action — try this Monday

Add a 3-point daily-cortisol checklist (mutation type, seizure med, bruxism) to your intake form and share red flags with the medical team.

02At a glance

Intervention
not applicable
Design
case series
Sample size
30
Population
other
Finding
not reported

03Original abstract

Rett syndrome (RTT) is a severe neurodevelopmental disorder resulting from mutations of the MECP2 gene. Hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis and abnormal stress responses have been observed in animal models of RTT, but little is known about HPA axis function among individuals with RTT. Diurnal salivary cortisol patterns from 30 females with RTT were examined in relation to mutation type, medication use, and features of the RTT behavioral phenotype. Cortisol patterns were significantly related to mutation severity, anticonvulsant medication status, and bruxism (tooth grinding). This study provides preliminary support for the hypothesis that RTT may be at risk for outcomes associated with aberrant HPA axis function, and that this risk may be mediated by mutation type.

American journal on intellectual and developmental disabilities, 2020 · doi:10.1201/b17198