A fascinating posting! As a fellow PT blogger, let me comment on a couple of things here off the top of my head. First, I just want to point out that Jung, who introduced and defined the psychological typology of introversion and extraversion, spelled the latter with an a rather o, i.e., extravert. Second, and more importantly, I am not sure that the existence of introversion can be reduced to the idea that "extroverts enjoy health advantages today only because we live in a period of rapid change, climatic, technological, and social." Actually, I question this correlation, because, since it is the outer world of people and things to which the extraverted type is primarily oriented, it seems to me that dramatic changes to their external environment would be more traumatic for the extravert than the introvert, who is primarily rooted and invested in his or her inner world. It may be that if, as you suggest, extroverts do indeed enjoy better health than introverts today, which is debatable, this could be rather the result of living in a far more extraverted culture today than did our ancestors. But I agree that introverts have more difficulty (and therefore experience greater stress) adapting to outer reality and can feel more alienated (and are more prone to observing the absurdities of existence) than do extraverts in general, which is certainly a source of anxiety and depression for them. Thy are a minority against whom the extraverted culture is prejudiced. Introverts may be more aware of their inner states, and therefore tend to report the presence of anxiety and depression more readily than their extraverted counterparts, who may be equally depressed or anxious, but deal with it differently: e.g., hyperactivity, manic socializing, workaholism, and avoidance of solitude. In my clinical experience, extraverts are just as prone to become depressed and/or anxious when their life style has become overextraverted or when they can no longer avoid introversion. I agree that the chronic repression of anger or rage is a pervasive collective problem, one which, I agree, can lead to all sorts of both physical and psychological problems. However, I am not at all sure that introverts tend to repress their anger or rage or "hostility" more than extraverts, but definitely may deal with it differently, and, indeed, may be more in touch with it. (These would make excellent dissertations topics!) At all events, another way to look at why introverts are still around (though, from what I see, increasingly in the minority, at least here in California) is because nature recognizes the human need for introversion, and it is the introvert who innately knows how to do this, whereas the extravert does not. So it may be a matter of nature trying to compensate for too much extraversion, or, perhaps at other periods, for too much introversion. And let's remember that some contemporary cultures are more introverted than others. Anyway, just some thoughts. Thanks for yours!
Extroversion
Do Extroverts Manage Stress Better?
The modern world favors extroverts but this cannot always have been true.
Posted Jan 05, 2017
Our society favors extroverts as the outgoing individuals who discover continents and sell stuff. Introverts are seen as relatively confined in their own inner world, making them potentially vulnerable to internally generated fears and anxieties.
Whether extroverts really are better at handling stress than introverts depends on two interrelated questions. First, are there genuine differences in how introverts and extroverts handle stress? If so, is the extrovert method more effective? One obvious place to start is with the social approach to handling anxiety.
Sharing Troubles
Extroverts are more social and more communicative. This means that they air their grievances rather than letting them fester.
People who let off steam in this way probably suffer less from intense anger and hostility that predicts anxiety-related illnesses including hypertension and heart disease. Admittedly, airing of grievances has a downside because it can aggravate conflicts. Yet, extroverts have better social networks and enjoy better social support from local communities, electronic networks, religious communities, and other organizations that are widely believed to protect health against the ravages of psychological stress.
Introverts and extroverts experience the world – and experience anxiety – in markedly different ways.
Anxiety
Extroverts are said to be stimulus hungry. It is as though their brains are not receiving enough stimulation to keep them alert. That is why they are outgoing and why they are motivated to seek stimulation by cultivating interesting activities and seeking out companionship. So an extroverted student might choose to study in a restaurant surrounded by other people and the din of human activities.
Introverts, on the other hand, behave as though they were over-stimulated. They prefer to study in quiet places where they can devote their undivided attention to the task at hand.
If extroverts are chronically under stimulated and therefore vulnerable to boredom, introverts are over stimulated and more vulnerable to anxiety.
Being more a prey to anxiety has many adverse consequences for health. To begin with, introverts are more prone to suicidal ideation (1) and may therefore be more likely to take their own lives – an action that can be interpreted as retreat from overwhelming over stimulation.
Depression and Heart Disease
Because they are more vulnerable to anxiety, introverts are at greater risk of clinical depression. At least one study with a small sample found that members of the clinically depressed population are more likely to be introverts (1).
Depression is biochemically linked to heart disease. Both show the same markers of inflammation (C-reactive proteins, 2). Introverts have less robust immune systems that could account for connections between introversion and both depression and heart disease (3). If introverts are more likely to bottle up hostility than extroverts, this would also make them more vulnerable to heart disease.
Evolution and Personality
The persistence of personality differences across populations implies that whatever the apparent health advantages enjoyed by extroverts in modern environments, human populations must have encountered environments in which introverts did better. Otherwise this personality polymorphism could not persist. Introversion would be removed by natural selection.
Evolutionary psychologists speculate that extroverts do better during periods of rapid change, such as that associated with changing rainfall, or glaciation. During periods of little change, extraverts would suffer from feelings of boredom and anxiety and they would be the ones with the health problems. Extroverts also have a likely advantage in attracting mates.
If that reasoning is correct, then extroverts enjoy health advantages today only because we live in a period of rapid change, climatic, technological, and social. In the relative monotone of much of human prehistory, introverts would have been happier and healthier.
Sources
1 Janowsky, D. S., Morter, S., and Hong, L. (2002). Relationship of Myers-Brigg type indicator personality characteristics to suicidality in affective disorder patients. Journal of Psychiatric Research, 36, 33-39.
2 Howren, M., Bryant, M. A., Lamkin, D. M, and Suls, J. (2009). Associations of depression with C-reactive protein, IL-1, and IL-6: A meta-analysis. Psychosomatic Medicine, 71, 171-186.
3 Vedhara, K., et al. (2015). Personality and gene expression. Psychoneuroendocrinology, 52, 72-82.