Sunday, February 24, 2008

Stress, Immune Response, and Illness

We often hear about the dangers of stress in our lives. We hear about stress contributing to a host of illnesses and also exacerbating existing illnesses.

But what exactly is “stress”?

We call environmental stimuli that cause us a physiological or emotional response, a “stressor”. Stress on our muscles is needed to make them stronger. Too much stress on them, or the same stress when they are not “warmed up” for it, can cause injury.

Our stress response is critical for our survival. Our body is taking action, responding to the environmental stimuli. If the stressor is dangerous bacteria, we rally the body’s defenses. We may have inflammation, and a rise of body temperature. We don’t feel well while this is happening, but our body is doing what it is supposed to do in this case.

We usually think of stress as an emotional reaction to a negative event such as studying for an exam or a death. But it can be a positive experience as well—going to a carnival, having a sleep-over with a best friend, or even going on vacation.

Often, one person’s negative “stress” can be another person’s pleasure. One person may get a thrill akin to a “high” from going on roller coasters. The bigger the better! Another person may react to the physiological changes such a “high” produces with extreme discomfort, psychological anguish, and aversion.

A lack of stress—good and bad—is an abnormal state and can quickly result in yet another type of stress. We’ve all heard that ubiquitous whine of, “I’m booored!” Without stress, we do not learn and grow in intellect and as human beings. In fact, we deteriorate, leaving us vulnerable to illness from minor stressors which normally our bodies and minds would have easily adjusted to.

So what do we mean by “stress” if everything in life is “stress”?

We mean all the above when the reaction is wearing us down rather than building us up. We include both stressors externally and internally, and both physical and emotional.

The child who loves math and is deprived of doing it is under stress. The child who hates math and is therefore immersed in it, is under stress. One child may love to socialize and thrives in a loud, active, spontaneous environment. If forced into too much quiet and seclusion, he will be under as much stress as the child who prefers quiet, solitary activities but is being forced into too much socialization. Some for each of them may be critical to help them to grow. Too much can wear them down.

Why does stress wear us down both physically and emotionally?

One reason revolves around our body’s immune response. Yes--even if the stress is psychological or emotional.

If you are at this website it is because your, or your child's, body (brain included), has been under stress. Although medically unexplained illnesses still are from physical causes, they cause stress in general which intertwines with psychological and emotional stress.

So back to our immune system.

We produce cytokines in response to the physical stress of fighting off illness. The cytokines are responsible for inflammation, and us feeling tired, achy and even for our thinking to feel “fuzzy”. But here is the weird thing. Our body produces this in response to emotional and psychological stress as well.

If something is already wrong physically, our body is under stress and already producing cytokines. We are thus much more vulnerable to emotional and psychological stressors. The same is true the other way around. If we are under tremendous psychological or emotional stress, we become vulnerable to physical stress. We tend to get sick more easily. These cytokines are more and more often in the news. They are now implicated in diseases ranging from diabetes, to heart disease, to bipolar and schizophrenia! And… there is evidence that the stage can even be set before birth by an increase in these cytokines within the mother’s own body[1].

Interestingly, antidepressants have some anti-inflammatory properties, and even aspirin, in one study helped schizophrenia symptoms. But guess what? So do some nutrients! Depression is accompanied by an inflammatory reaction as indicated by an increased production of pro-inflammatory cytokines. These cytokines are stress-sensitive. The resulting depressive behaviors may be due to increased catabolism of tryptophan, the precursor of serotonin. Depression is also accompanied by an IgM-related (auto)immune response directed against disrupted lipid membrane components (the brain is made up of a lot of lipids-ie fats.)[2] 

Even if a child has very little outside stress in his life, remember that his own illness can be causing a tremendous amount of stress. He may have very little reserve left for other physical or emotional stressors.

So how much stress is the “right amount”? Especially in light of the fact that too little is also damaging. What stress is “wrong”? What do we do to mitigate the damage from having to cope with normal life stress? After all, normal life stress is unavoidable, yet these kids, already wracked by illness, are left exposed and vulnerable to that stress.

That’s where things get really murky.

And that’s what we’ll talk about next: Stress and Our Children. How Much is Too Much?

About Cytokines:
Cytokines and Depression Online by Professor Ronald S. Smith

For a nice, but scientific, discussion (old but still quite relevant) of the inter-relatedness of immune response (cytokines), the endocrine system (adrenal stress response) and the hypothalamic (brain)-pituitary axis, see: Regulation of the Hypothalamic-Pituitary-Adrenal Axis by Cytokines: Actions and Mechanisms of Action PHYSIOLOGICAL REVIEWS Vol. 79 No. 1 January 1999, pp. 1-71

And more about Cytokines and the Brain:

[1] Immune-System Gene Linked to Schizophrenia Development
[2] The cytokine hypothesis of depression: inflammation, oxidative & nitrosative stress (IO&NS) and leaky gut as new targets for adjunctive treatments in depression.

Cytokines and the Brain: Implications for Clinical Psychiatry
The time of prenatal immune challenge determines the specificity of inflammation-mediated brain and behavioral pathology.
A comparison of some indices of innate and adaptive immunity in different types of schizophrenia
Cortisol and Cytokines in Chronic and Treatment-Resistant Patients with Schizophrenia: Association with Psychopathology and Response to Antipsychotics

And to show just how long ago this connection between immune response on its effect on the brain has been studied (no, this is not really "new news"), take a look at the dates on these articles:

Books of Possible Interest:
Buddha's Brain: The Practical Neuroscience of Happiness, Love, and Wisdom , Cytokines: Stress and Immunity, Second Edition


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Last Update:  3 September 2011


Herb said...

An argument might be made that the production of cytokines, and other substances involved in dealing with stress, by the body, consumes nutrients required for their production. These nutrients are required by the body for production of substances needed for normal functions not just "fight or flight". Since "fight or flight" takes priority, chronic stress robs the body of the nutrients that it needs for proper function leading to symptoms that we call disease including so-called mental illness.

Jeanie said...

Thank you for a terrific segue into another article that is definitely needed -- a discussion about stress and nutrition. Hmmm... I guess it would apply to depression, as well.

Herb said...

The body produces everything needed for life from nutrients but good nutrition, alone, may not be adequate for therapewtic purposes. For example,sometimes, impairment to the body's ability to process nutrients results in a shortfall in needed enzymes, hormones, etc. This is probably the
reason supplements are required, as in the case of, say, CoQ10 which is produced in the liver from various nutrients that we ingest. If the liver is impaired or prevented by medication or a cascade effect, it cannot produce adequate amounts even with good nutrition and the body requires supplementation.