In this video I introduce the unit on health psychology by defining several key terms and discussing the challenges of understanding the causes of illness. I describe etiology (or aetiology), epidemiology, the use of retrospective & prospective studies, and the dangers of coincidental correlations. I also consider how psychological factors may influence health, whether in the extreme of “voodoo death” or “psychophysiological death“, or by influencing the expression of symptoms in psychosomatic illnesses.

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Video Transcript

Hi, I’m Michael Corayer and this is Psych Exam Review. In this unit we’re going to start looking at health psychology with an emphasis on understanding how psychological factors can influence health, illness, and recovery. In this video we’re going to look at some of the key terms for talking about health psychology and then we’re going to consider some of the challenges of investigating this relationship between psychological factors and health.

Now one important key term here is etiology, and you may also see this spelled with an a in the front, and etiology refers to the origin or causes of an illness. And a related field here is epidemiology. So epidemiology involves investigation of the frequency and distribution of an illness within a population, as well as the possible causes of that illness.

Now in epidemiological studies one of the main challenges that we have is that it’s very difficult to establish causation and the reason for this is that we can’t experimentally cause particular illnesses. It would be unethical for us to give people things that we think are going to cause an illness. So we might think that a certain factor is associated with an illness but then we can’t manipulate that and expose people to it in order to see if they develop the illness.

So instead we rely on what are called retrospective studies, and so in a retrospective study what we do is we find people who have already been diagnosed with the illness that we’re interested in and then we attempt to look back over their lives retrospectively to see what variables might have been involved in the development of this illness. Now one of the main problems here is that this immediately opens the possibility of bias in terms of which factors we look at in their previous life and how much we think those factors are important. So for instance, if someone develops heart disease and they think there’s a relationship with heart disease and stress, if I now ask them to look back on their prior levels of stress, they might have a tendency to exaggerate because they think “well part of the reason I have heart disease now is because I had so much stress before” and so that would distort their reporting of their stress level. When if they hadn’t developed heart disease, maybe they would have assessed their stress level differently.

So this is one challenge, and another challenge is that we’re looking at many possible variables. And so if we look at lots of variables and we look at lots of possible outcomes, lots of possible illnesses that you can develop, some of the relationships we find might just be coincidental. This is part of the reason you often see conflict in epidemiological studies. One study says that red wine is good for you, another says that red wine is associated with some negative outcomes, another says coffee is good, another says coffee is bad, eggs are good, eggs are bad.

We have this problem because if we look at a large number of variables and a large number of possible outcomes, the chances of finding something are pretty much guaranteed. But we don’t know for sure if what we found is a real relationship or an illusory correlation; a coincidence. This is especially true when we look at studies that involve assessments of mortality or longevity because, of course, people die for many reasons and the exact causes of their death could be very complicated and could involve multiple factors. So if someone in our study dies, or a small number of people in our study died, then this might change the overall mortality or overall longevity of the group, even though it might not actually be directly related to the variables that were investigating.

So these are some big challenges for epidemiological studies and ideally what we do is what are called prospective studies. So in a prospective study we track many healthy people over time and then we see who becomes ill. So we measure these variables over time in healthy people and then we see which people develop which illnesses, and then we have already recorded a track record of the variables we think might be related. And we can look if there are actually patterns.

Now the problem with prospective studies is that they’re very time-consuming. These types of longitudinal studies take a very long time to conduct and they’re very expensive. And the other problem is most of the illnesses that we’re interested in are the diseases that accumulate slowly over time. We want to know about things like heart disease, or cancer, and these happen over the course of decades. That means our studies have to last for decades and that makes them especially time-consuming, especially expensive. And many of the acute illnesses that are developed in much shorter periods of time are ones that we already understand quite well and that we’re actually already able to treat very effectively.

We can also consider how psychology relates to illness. Can psychological factors actually cause an illness or can they even cause death? Walter Cannon, who we learned about in the Cannon-Bard theory of emotion as well as when I discussed the sympathetic nervous system and the fight-or-flight response; that term was coined by Cannon, he became interested in what was called voodoo death. These were situations where a person in a tribe is cursed by a shaman or a community leader and that person subsequently dies. Cannon suggested that this could be due to over-activation of the sympathetic nervous system that this additional stress and activation of the sympathetic nervous system, because of their high anxiety that they had been cursed, could actually cause them to die.

Now there are some other possible explanations of this “psychophysiological death“; this is another term for voodoo death that avoids the cultural insensitivity of calling it “voodoo death”. So we might wonder, well, maybe the shaman cursed somebody who was already ill and in that case the person died from the illness; it was not directly caused by the cursing or from the psychological aspects of being cursed. Or maybe the shaman would use poison. This, of course, would cause the person to die. It would also convince others of the shaman’s power. Or it could also be the case that the person who is cursed is now shunned by the rest of society. And if you’re living in a small group or a tribe you depend on other people more directly for your own survival. And so if you’re no longer part of the group, if you are shunned by everyone else in your community, then your chances of death from dehydration or starvation when others refuse to share with you might be higher. Or they might view you as a lost cause. You should not bother sharing food with because you’re cursed and you’re going to die anyway.

So can beliefs cause illness? This is sort of a softer version of this question. We might not think that we can be sure that beliefs can cause death, but how about illness? But one way we can think about this are what are called “psychogenic illnesses” and this literally means originating from the mind; psychogenic. One of the problems with investigating psychogenic illness is that sometimes we might think something’s originating from the mind but that’s just because we don’t know where it’s coming from. So we can’t seem to find any physiological explanation and so we might assume that it must be a psychological explanation. But it could be the case that it’s just a physiological explanation we haven’t discovered yet. It could be a bacteria we don’t know about, it could be a virus that we don’t understand, it could be levels of some hormone or it could have something to do with receptors for that hormone. There could be some legitimate cause some physiological cause of an illness and until we found that, we might believe it’s a psychogenic illness.

This is distinct from “psychosomatic illness“. So what psychosomatic illness refers to is situations where symptoms arise from thoughts or beliefs; where there are psychological factors that are influencing the symptoms of an illness. This is not to say that they are the cause of the illness. There could still be an underlying physiological cause of the illness like a bacteria or something, but that the expression of the symptoms or the worsening of the symptoms is associated with thoughts and beliefs.

We can see examples of this in things like a relationship between stress and asthma attacks. Stress is not the cause of asthma but we do know that levels of stress can influence the symptoms and the expression of symptoms and work to increase the frequency and the severity of the asthma attacks. This brings us to a field known as psychoneuroimmunology. This is a field that looks at the relationship between stress, psychological factors, health and the function of the immune system. Ok, I hope you found this helpful, if so, please like the video and subscribe to the channel for more. Thanks for watching!