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Aug 102010
 

This article from Wired describes the work of Robert Sapolsky, who studies stress. It gives a good overview of the causes and costs of stress, some suggestions for how to cope, and fascinating news about work toward a vaccine against stress.

Sapolsky’s book Why Zebras Don’t Get Ulcers, Third Edition describes how the body reacts to stress. In essence, the stress response is a dramatic shift from long-term functions (building bone, reproducing, general maintenance, etc.) in favor of short-term needs like running or fighting. In a zebra, the stress response kicks in when needed—for example, when a predator appears. If the zebra escapes being killed by the lion, it’s done being stressed, and its body can get back to maintenance and upkeep. The problems in humans (and other primates) arise when a chronic state of stress sets in. Zebras don’t get ulcers because they don’t like awake at night worrying fruitlessly about whether they said the right thing to the boss, or if they’re going to be able to make the mortgage payment this month.

The Wired article describes how social status affects stress; low-status baboons first alerted Sapolsky to the unfortunate effects of being low on the social ladder. Further studies in humans across a variety of fields have confirmed the effects. The presence or absence of control appears to be crucial to the way status mediates stress: if you have more control (which is typically associated with higher status), a demanding workload is easier to cope with than a dead-end job where you have little control.

The article suggests some things that you can do to help relieve stress (surprisingly, exercise is listed as being good for you only if you enjoy it overall—if you’re forcing yourself and gritting your teeth to get through it, maybe you should just stay home). It also describes some fascinating work on a vaccine for stress. It uses a reconfigured version of the herpes virus; all the harmful genes have been removed and replaced by various neuroprotective genes. This vaccine has been found to limit cell damage in rodents who have undergone a massive release of glucocorticoids (stress hormones). I was very impressed by this; it’s still nowhere near ready for humans, but it’s amazing to me that it could be done at all.

I really hope this work pans out in the long run and provides a stress vaccine for humans. I’d be tempted to say why bother doing all that when people can just exercise, meditate, or try to find other ways to control their stress. However, I know from personal experience that it can be extremely hard to do that. Sometimes it feels like my body has a mind of its own when it comes to stressing out, even over relatively trivial things. The reason it can be hard to combat stress is that the stress response operates on a kind of positive feedback loop. Basically, once your body and mind consistently get the idea that life is dangerous and that fear or caution is appropriate, it’s hard to persuade them otherwise. If you’re chronically stressed, you’re more sensitive to the effects of future stressors, and stresses that happen early in life can cast a very long shadow. The saddest part of the whole thing was probably this:

A recent study found that individuals abused by their parents during early childhood showed epigenetic changes to their DNA, which altered how their genes were read. The most prominent changes involved genes encoding glucocorticoid receptors, which led to a magnified stress response. The abuse might be temporary, but the damage is permanent, a wound that never heals.

It would be a wonderful world if children were never exposed to treatment or conditions that had the potential to hurt them for the rest of their lives, but that’s not possible. I hope that all the various stress-combatting activities can help even those with such a magnified stress response, but still, I wish Sapolsky and his colleagues success in their work on a human anti-stress vaccine.

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Oct 082008
 

I’ve heard the meditation practices of Buddhism described as a sort of toolkit for improving the quality of life, and in the past few years I’ve blogged a few stories about the mental benefits of meditation. Those were mostly about forms of meditation that emphasize calm concentration, which may improve the ability to focus the attention and block out distractions.

A recent study examined the physiological effects of another form of meditation, compassion meditation, which aims to bring gentle awareness to our interactions with others and encourage feelings of benevolence for other people. Sixty-one college students participated in the study. It appears that the amount of time spent engaged in compassion meditation may affect how well the body handles psychosocial stress. Those who spent more time meditating responded to a stress test with less emotional discomfort, and also with lower blood concentrations of two stress hormones. The latter effect, if borne out by later studies, could mean that this form of meditation is a useful tool in fighting stress- and inflammation-related diseases. (Because I don’t want to speak of fostering compassion solely in terms of what it can do for your immune system, useful as that may be, it’s also worth noting that if you’re curious about how compassion meditation affects the quality of your own mental health, you can visit the Lovingkindness Meditation page on the Wildmind Buddhist Meditation site.)

This press release on EurekAlert has an overview. The paper, Effect of compassion meditation on neuroendocrine, innate immune and behavioral responses to psychosocial stress, by Thaddeus W.W. Pace, Lobsang Tenzin Negi, Daniel D. Adame, Steven P. Cole, Teresa I. Sivilli, Timothy D. Brown, Michael J. Issa, and Charles L. Raison, is in press in the journal Psychoneuroendocrinology.

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Apr 232008
 

If you read much about depression, you hear right away about serotonin, and maybe dopamine, neurotransmitters that are believed to be crucial to feelings of well-being. I hadn’t realized that stress hormones, in particular corticotropin releasing factor (CRF), are also implicated in depression. Overactivity in a particular area of the hypothalamus that produces CRF often occurs in depressed people. In a recent study, researchers used a technique called micro-laser-dissection to examine postmortem human brain tissue in fine detail. They looked at the appropriate region of the hypothalamus in seven depressed people and seven non-depressed control subjects, and found significant differences between the two that apparently reflect increased CRF activity in the depressed brain. Further studies of stress hormones and depression could lead to a new class of antidepressants. We can only hope.

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Apr 072008
 

Norman Cousins pioneered the idea of using humor as part of the treatment for medical illnesses, in conjunction with other therapies. Nearly 45 years ago he wrote a book, The anatomy of an illness, detailing his experience in using humor as part of his plan for overcoming a serious disease. At the time I don’t know that it was taken all that seriously by the medical establishment. However, the mood/health connection has been explored since then, including a recent study that found that not just laughter, but the anticipation of laughter, increased blood levels of two beneficial hormones (beta-endorphins, good against depression, and human growth hormone, good for the immune system). A follow-up study has found that the anticipation of laughter also decreases the levels of stress hormones, including cortisol and adrenaline. It looks like laughter is not just good medicine, but maybe also good preventive maintenance for the body.

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Mar 172007
 

It’s more rat research today. In this study (carried out by a team led by Daniel Peterson at the Rosalind Franklin University of Medicine and Science), rats who were socially stressed showed a lower survival rate for new-born brain cells in the hippocampus. The stress consisted of young rats being exposed to older and meaner rats, who ganged up on and sometimes bit the younger rats. (This is why they use rats instead of people.) The hippocampus, active in processing emotions and memories, is one of two areas of rat and human brains where neurogenesis occurs. The stress of an encounter with an aggressive older rat didn’t seem to slow the generation of new neurons, but it did significantly lower the survival rate of the new brain cells. The loss of these brain cells may be one factor in the development of depression. Bad news for anyone enmeshed in a socially stressful situation, but the good news is that there is a delay between the stressor and the effect, so perhaps some kind of treatment could negate the bad effect of the stress. It would be interesting to know the mechanisms involved, e.g., what role, if any, do stress hormones play.

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Feb 272007
 

Here’s an article from Science Daily about Robert Sapolsky’s research into primate behavior and stress. Sapolsky, a neuroscientist at Stanford, has written an excellent book about how humans respond to stress (Why zebras don’t get ulcers), and this article sums up some of his material on how our fight-or-flight response works against us when we’re reacting to psychological rather than physical threats. Basically his point is that while we’ve eliminated or reduced many of the dangers that used to threaten us, our lives haven’t gotten any easier because we’re putting our energy into interacting with each other, often in stressful ways. This article provides a nice overview of some of the things we know about stress and its effects on health and happiness.

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Feb 282006
 

For some reason, male and female rats respond differently to a combination of isolation and stress. The females coped much better, reacting with a stronger immune response when their immune systems were challenged after a prolonged period of isolation and a brief period of acute stress. This press release from EurekAlert describes the research and some attempts to begin to explain it. The explanations are vague and to my mind raise more questions than they answer: maybe it’s something to do with motherhood, maybe something different in how the females perceive the stressor. More interesting is the connection to humans: men are more likely to become ill or die when socially isolated than women are. It’s also interesting that this challenges the common idea that stress is bad for your immune system. Evidently not all stressors are equally distressing to all those who experience them. (Never mind that a concept like “social isolation” might differ drastically depending on who’s describing it. I expect my optimum conditions might seem like relative isolation to some extroverts.)

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Jan 202006
 

Leptin, which has been recognized for awhile as a key hormone in controlling appetite and weight, is also linked to depression, at least in rats. It makes sense that appetite is linked to mood; who hasn’t felt too anxious or depressed to eat? But it’s not clear how this recent work with rats might translate to humans. (Leptin was supposed to be a big anti-obesity drug because of how it acted in rats, but it didn’t work the same for people.) In a recent study, stressed rats had lower levels of leptin in their blood and also showed signs of depression, which were reversed when the rats were given leptin injections. If leptin does turn out to be useful in treating human depression, scientists would likely need to develop a way to reproduce the effect with another molecule that has only the anti-depressant effects, to avoid side-effects due to all the other roles that leptin plays in the body. I suspect we’re in such early days in figuring out how this all works that people are going to look back 100 years from now and be amused at our misconceptions based on the bits and pieces we know so far, but we’ve got to keep gathering the bits and pieces to try to assemble them into a coherent picture. (There’s a technical term, by the way, for the particular type of stress the rats were subjected to: chronic unpredictable stress, or CUS. I’ll have to try that one out in conversation the next time I’m complaining about my job.)

http://www.nature.com/news/2006/060116/full/060116-3.html

http://www.medpagetoday.com/Psychiatry/Depression/tb/2496

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