These releases occur in seconds and help fuel our natural fight-or-flight response – the jolt that enables us to focus and react, and right our fishtailing cars. When these chemical messengers work well, they help us navigate around life's punches: a fever breaks, a bad mood lifts, pain subsides. But, when one or more of these chemical messengers doesn't do its job just right, the balance can go down with the punch. Stress hormones also control other chemical messengers that influence biological processes such as body temperature, heart rate, blood pressure, appetite, metabolism, mood, sleep, fertility, pain perception and immune system responses.

In Currie's case, his psoriasis was significantly linked to stress. In fact, a Finnish study found that men, in particular, were more likely to experience psoriasis and joint pain when stressed. "It's cyclical," says Currie, "because the stress level will impact my arthritis, and the arthritis will impact my stress level."

Shared Pathways Deliver Stress

Because people with arthritis are already experiencing inner body stressors that affect cortisol production due to their disease, researchers are now examining how cortisol levels are affected by external daily stressors in people who have arthritis, as well as in those who don't.

Researchers at Pennsylvania State University's Milton S. Hershey Medical Center in Hershey, recently studied how a stressor such as sleep loss (six hours of sleep instead of the recommended eight) affected 25 young, healthy college students. After one week with less sleep, the students' blood tests showed decreases in cortisol and increases in cytokines, chemicals that spark inflammation – changes also found in people with RA even when they get a full night's sleep.

With chronic stressors like consistent sleep loss, would the healthy college students be more susceptible to developing RA? While experts agree that many factors, including heredity, likely contribute to a person's chances of developing conditions like RA, stress is one of the suspected culprits. The reason? The stress response and the immune response share some of the same pathways.

"The processes that fire up the immune system and lead to the proliferation of inflammation-inducing chemicals are the same processes that are stimulated by stress," says Alex Zautra, PhD, an Arthritis Foundation-funded researcher and professor of psychology at Arizona State University in Tempe.

Some experts believe there's a chicken-and-egg predicament involved: Immune system hiccups can cause stress, and stress can cause immune system hiccups in susceptible people. Who's susceptible? Experts say it depends on how we are "wired."

Some Are Wired for Stress

Researchers have a number of theories about how people become wired, or rather miswired, for stress. For instance, exposure to chronic, ongoing stressors such as living with arthritis or caring for an aging parent, can impact chemical messengers. Ohio State University, Columbus, researchers measured an inflammatory chemical in older adults and found those who were taking care of a chronically ill spouse had four times the amount of it in their blood compared to non-caregivers. The increased inflammation marker persisted in the caregivers years after the sick spouse died, indicating that changes to stress circuitry can have long-lasting effects.