From Forbes.com:

Low levels of a stress hormone may be responsible for the obsession with routine and dislike for new experiences common in children with a certain type of autism.

U.K. researchers found that children with Asperger syndrome (AS) do not experience the normal twofold increase of cortisol upon waking up. Levels of the hormone in their bodies do continue to decrease throughout the day, though, just as they do in those without the syndrome.

The body produces cortisol, among other hormones, in stressful situations. Cortisol increases blood pressure and blood sugar levels, among other duties, to signal the body's need to adapt to changes occurring around it. It's thought that the increase shortly after waking helps jump-start the brain for the day ahead, the researchers said.

People with Asperger syndrome notably have very repetitive or narrow patterns of thought and behavior, such as being obsessed with either a single object or topic. Though tending to become experts in this limited domain, they have otherwise very limited social skills, according to the study.

"Although these are early days, we think this difference in stress hormone levels could be really significant in explaining why children with AS are less able to react and cope with unexpected change," study co-leader Mark Brosnan, from the psychology department at the University of Bath, said in a news release issued by the school.

If these Asperger symptoms are caused primarily by stress, caregivers could learn to steer children away from situations that would add to anxiety, the researchers said.

"This study suggests that children with AS may not adjust normally to the challenge of a new environment on waking," study researcher David Jessop, from the University of Bristol, said in the news release. "This may affect the way they subsequently engage with the world around them."

The researchers, whose findings were published in the journal Psychoneuroendocrinology, will next study if this lack of cortisol upon waking also occurs in children with other types of autism.

From the Daily Mail (U.K.):

A simple saliva test could help doctors identify patients most at risk of a life-threatening stroke.

New research shows that high levels of the hormone cortisol in saliva are directly linked to the build-up of fatty deposits in arteries carrying blood to the brain.

When these deposits - called plaques - break loose, they can cause a blockage that starves the brain of blood and oxygen.

Research published in the Journal of Clinical Endocrinology and Metabolism suggests many strokes could be prevented if doctors routinely tested patients' saliva.

Strokes are the third most common cause of death in England and Wales, after heart disease and cancer. They occur when a clot cuts off the blood supply to the brain.

Clots are often caused by fatty deposits that get dislodged and travel towards the brain. Once they get into smaller blood vessels in the skull, they cause a blockage.

In the latest study, experts at the Erasmus Medical Centre in Rotterdam, Holland, and the Technical University of Dresden in Germany tested volunteers to see if cortisol levels in their saliva pointed to diseased arteries.

Each volunteer provided four saliva samples throughout the course of one day and underwent ultrasound tests to check for plaque deposits in their carotid arteries (in the neck).

The results showed those with the highest cortisol levels also had the largest build-up of plaques.