Hypothalamic-pituitary-adrenal (HPA) axis activity in adults with intellectual disabilities: a preliminary investigation.
Saliva samples show a flat morning cortisol jump in adults with ID, flagging hidden stress you can act on.
01Research in Context
What this study did
Researchers collected saliva from the adults with mild or moderate intellectual disability.
They took four samples per day for two work days.
Staff helped clients drool into tubes at wake-up, 30 min later, afternoon, and evening.
The team also rated each adult’s anxiety and aggression.
Goal: see if cortisol patterns look like those of typical adults.
What they found
Clients could give usable spit with minimal help.
Daily cortisol slope was normal—high in morning, low at night.
But the 30-minute jump after waking (the CAR) was flat.
Lower CAR linked to higher anxiety and aggression scores.
How this fits with other research
Varela et al. (2023) saw the same flat CAR in autistic kids, and IQ predicted it.
Together the two papers show the blunted CAR spans ID and ASD, so it may mark stress across developmental disabilities.
Fullana et al. (2007) found 4 in the adults with mild-moderate ID already screen positive for depression.
Prigge et al. (2013) now adds a body-stress marker that may explain why those mood symptoms stick around.
van Schrojenstein Lantman-de Valk et al. (2006) showed life events predict later behavior problems; flat CAR could be the biological channel that turns life stress into aggression.
Why it matters
You now have an easy, low-cost way to spot chronic stress in clients who can’t label it.
Add two extra saliva tubes to morning routines.
If the wake-up rise is absent, plan proactive breaks, teach coping skills, and track whether the CAR returns as behavior improves.
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02At a glance
03Original abstract
BACKGROUND: Cortisol is a marker of physiological arousal, exhibiting a characteristic pattern of diurnal activity. The daily cortisol profile has been xamined extensively and is atypical in a number of clinical disorders. However, there are very few studies focussing on the cortisol profile in adults with intellectual disabilities (ID). This paper reports a preliminary investigation into the nature of the cortisol profile in adults with mild or moderate ID and provides reflections on the challenges of psychophysiological research in this population. METHODS: On two consecutive days, 39 adults with mild or moderate ID each donated saliva samples for cortisol analysis, at multiple times between waking and evening. A comparison between these data and the published literature permitted a descriptive assessment of the cortisol awakening response (CAR) and diurnal profile. A variety of psychometric measures and an assessment of behavioural history were also collected in order to describe aspects of the participants' emotional and behavioural states. RESULTS: Individuals with ID exhibit a diurnal cortisol secretion profile, qualitatively similar to that of the typical, healthy, adult population. However, the findings also suggested a blunted CAR, warranting further investigation. There was also some evidence that cortisol secretion was affected by anxiety and a recent history of aggression. CONCLUSION: While further work is required to characterise the CAR fully, there was no indication that the diurnal cortisol profile among people with ID differs from that of the typical population. This study also demonstrates that, although challenging, it is feasible, and acceptable to participants, to collect repeated physiological measures from men and women with mild and moderate ID.
Journal of intellectual disability research : JIDR, 2013 · doi:10.1111/j.1365-2788.2012.01557.x