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Posted by on Jan 24, 2013 in Critical Thinking, Evolutionary Psychology | 14 comments

Skepticism & evolutionary medicine

Evolutionary medicine is an emerging field, and one of my principle research interests. Evolutionary medicine helps explain many ailments and diseases. For example, the fever response, which is an immunoresponse and not caused directly by any pathogen. Another example comes from primatologist Robert Sapolski, who wrote a wonderful book about how stress damages every system in the body and why, called Why Zebras Don’t Get Ulcers. Our current understanding of why our preferred diets (high fat, salt and sugar) tends to cause diseases like diabetes is pure evolutionary psychology: we evolved tastes for things which were both rare and incredibly valuable to survival in a by-gone era. When I have before written that evolutionary psychology is both successful and expansive, these are part of the evidence. You probably know of some of these without having thought of them as evolutionary psychology.

A familiar and high-profile example is antibiotic resistance. The misuse of antibiotics can directly lead to the evolution of nastier, resistant bugs. I was fortunate enough to have lunch the other day with a specialist in this area, who had come to UCLA to brief the doctors here. Here are a few interesting bits that came up in our discussion.

The flu shot might actually be bad for you, in the long haul. Infections from the actual pathogen induce superior “lateral” resistance versus the vaccine. What this means is that infection from the flu better primes your immune system to fight off mutant, similar forms in the future versus than if you had got the flu shot and never contracted the actual flu. There are other considerations, of course. Without vaccinations, many more people will get the flu in any given season which induces an economic and medical cost. Groups that are at serious risk of death from the flu, such as infants and the elderly, should always get vaccinated. Nonetheless, it is good to know these things.

Medical researchers are innovating new ways to use antibiotics which use evolutionary mechanisms to our advantage, instead of disadvantage. One such method is the use of antagonistic pairs or groups of antibiotics. It is possible to have two related antibiotics, let’s call them A and B. If you use A, most of the bugs die, but the few remaining which are resistance to A survive and reproduce and eventually dominate. However, such resistance some in the form of a modification of particular receptors on the bacteria such that more resistance to A means less resistance to B. The harmful bacteria is thus selectively bred for vulnerability and B can then annihilate it.

In cancer treatment, the mindset that a tumor must be destroyed asap might not be the best strategy in all cases. This is true because cancer is actually evolution in progress within your own body. What you use to treat a tumor influences the evolution of that tumor, perhaps leading to resistance to chemotherapy as a result of using it. An alternate strategy was testing in mice: use chemo only when the tumor is growing and not otherwise. In the study, some of the mice who recieved traditional treatment were dead, but 100% of the mice which recieved the alternate tumor management treatment were alive at the end of the study.

The skepticism part

What I have heard, is that doctors tend to rely too heavily on established precepts and are reluctant to reconsider them. One example given above pertains to cancer. Another is the advice we’ve all heard that we should always continue a line of prescribed antibiotics until they are gone. The logic of this advice is simple, make sure the antibiotics have time to kill every single germ they can to prevent a resurgence. But from the evolutionary medicine perspective, this can be self-defeating: you’ve just incubated resistant versions which you may have no ability to fight off later. Had you used no antibiotics (here I’m assuming we’re talking about non-lethal illness, such as an ear infection) your body would subsequently have a strong resistance to that germ and many similar mutants in the wild. You would not have incubated a super-bug.

This is a very controversial and ethically complex point: it isn’t just that we should not over-prescribe antibiotics, it’s that often we should not prescribe them at all, even if they work. The purpose in taking antibiotics is very often to end a painful or uncomfortable illness more quickly, not to save your life. Most infections are not life threatening. But in doing this, we’ve traded comfort for long term risk. Sometimes, short term risk. The antibiotics your doctor gives you today could directly lead to the evolution of bugs which kill you a year or ten years from now. This is not something that most doctors are thinking about, and generally, that they want to think about.

  • http://www.facebook.com/Scott1328 Tim McCollough

    About a month ago you asked people to post questions about Evo Psych and then you would answer some. What happened? I noticed that PZ also promised a thorough take down of EP but all he accomplished was wealth of quote mines for the creationists in his attempt to demolish adaptationism.

    • http://www.www.skepticink.com/incredulous Edward Clint

      Quite right! I will post a reply to the first couple questions in the next few days.

  • Ronlawhouston

    I think doctors think about it but simply have vastly different opinions on the best way to approach the issue. I know many pediatricians are very loathe to prescribing antibiotics. I think others take the position that if the patient is suffering and antibiotics can shorten the suffering they’ll prescribe them.

  • http://www.facebook.com/djgrothe D.J. Grothe

    Love Sapolsky and appreciate the growing intersection of evolutionary medicine, transhumanism and concierge doctors. Now to hear a skeptic’s take on things like 23andme.

  • Ingemar Oseth

    “Our current understanding of why our preferred diets (high fat, salt and
    sugar) tends to cause diseases like diabetes is pure evolutionary
    psychology: we evolved tastes for things which were both rare and
    incredibly valuable to survival in a by-gone era.”

    Is this not evolutionary physiology? The body’s demand for fats, salt, and sugar are physiological.

    “In cancer treatment, the mindset that a tumor must be destroyed asap
    might not be the best strategy in all cases.”

    This is only true of specific types of cancers and should not be generalized.

    “What you use to treat a tumor influences the evolution of that tumor, perhaps leading
    to resistance to chemotherapy as a result of using it.”

    This adverse effect of chemotherapy is well known. It is a major engine driving the growth of genetically specific chemotherapy.

    “This is a very controversial and ethically complex point: it isn’t just that we should not over-prescribe antibiotics, it’s that often we should not prescribe them at all, even if they work.”

    This is not ethically complex. Main stream medical standards of care have long (years and years) advocated against prescribing antibiotics unless they are medically necessary.

    • http://www.www.skepticink.com/incredulous Edward Clint

      “Is this not evolutionary physiology? The body’s demand for fats, salt, and sugar are physiological.”

      But our desires are psychological. Of course, it is also physiological.

      “This adverse effect of chemotherapy is well known. It is a major engine driving the growth of genetically specific chemotherapy.”

      I’m not a doctor or expert in this area; I was merely reporting on someone who’s job is to brief doctors. According to that source, there are many doctors who don’t agree with this, even that actively resist the idea.

      “This is not ethically complex. Main stream medical standards of care have long (years and years) advocated against prescribing antibiotics unless they are medically necessary. ”

      I think that it is. The meaning of the expression you use “medically necessary” isn’t always clear. Is it alleviating suffering now? or is it reducing long term risk? Is it ethical to permit some to (statistically) die because of a loss of herd immunity if the average medical quality of life over the lifespan improves significantly? Maybe this is all simple to you. It isn’t to me.

      • Ingemar Oseth

        Edward writes;

        “But our desires are psychological. Of course, it is also physiological.”

        It appears you are overreaching. This sort of mission-creep is not uncommon as practitioners, especially those new to a field, attempt to explore the boundaries of their areas of interest or expertise.

        “I’m not a doctor or expert in this area; I was merely reporting on
        someone who’s job is to brief doctors. According to that source, there
        are many doctors who don’t agree with this, even that actively resist
        the idea.”

        I suggest you examine additional sources. The National Institutes of Health website is always my first stop.

        “The meaning of the expression you use “medically necessary” isn’t always clear. Is it alleviating suffering now? or is it reducing long term risk? Is it ethical to permit some to (statistically) die because of a loss of herd immunity if the average medical quality of life over the lifespan improves significantly? Maybe this is all simple to you. It isn’t to me.”

        In your response you somehow jumped from the subject of medical necessity in prescribing antibiotics to vaccination. The former has long been addressed by the standards of care, although advances in medicine often create gaps between standard practice and the latest proven techniques. Physicians who prescribe antibiotics when they are not indicated for treatment are, of course, engaging in a violation of these standards of care. It is also an ethical issue, but a very different one than non-vaccination. This is also patient driven, but physicians are for the greater part powerless to override the wishes of those who refuse vaccination. See the difference?

        Perhaps the confusion comes from the fact that “medical necessity” is specific to the needs of each individual patient, and as such becomes a very narrow term. For example, end of life care for a patient dying from complications of COPD will include the administration of drugs and treatments that are medically necessary for the patient’s comfort, but can have no effect on the outcome.

        Here is an ethical brain teaser for you. Polio was the AIDS of its era in the US. The search for an effective vaccine went on for decades. The Salk vaccine was created using “wild” strains of polio. It was successful, but carried with it a known probability that a number of people who received the inoculation would become infected with polio. With this in mind federal and state governments ordered the mandatory immunization of children. Although the numbers are in unclear, perhaps as many as 250,000 children acquired polio for the vaccine with varying outcomes ranging from death to slight long-term effects. One the plus side, many more were made immune from the disease, and in the end, more lives were saved. What are the ethical issues surrounding the decision to require children to be vaccinated with the Salk vaccine?

        • http://www.www.skepticink.com/incredulous Edward Clint

          “It appears you are overreaching”

          No. Eating is behavior, and a behavior that has a body of psychological literature behind it for many decades, in both humans and animals. Psychologists study behavior and anthropologists, behaviors in cultures.

          “I suggest you examine additional sources. The National Institutes of Health website is always my first stop.”

          Good idea. I will.

          • Ingemar Oseth

            “No. Eating is behavior, and a behavior that has a body of psychological
            literature behind it for many decades, in both humans and animals.
            Psychologists study behavior and anthropologists, behaviors in cultures.”

            Overreaching…… since evolutionary physiology more powerfully influences evolutionary medicine than a softer science like psychology. It seems you wish to invade the province of the former.

            It is noted you elected to pass over the majority of the other information in my previous comment. Evidently you wish to avoid a substantive discussion of the very subject you broached in your essay. Perhaps you might change your mind if engaged by someone who has less experience in healthcare than I. That way you will have a much better probability of avoiding meaningful challenges to your preconceived notions about standards of care, and so on. :)

          • http://www.www.skepticink.com/incredulous Edward Clint

            Evolutionary psychology isn’t a domain, strictly speaking, the way that genetics or physiology is. It’s an approach to answering ultimate questions and it takes as inputs the findings of many fields such as artificial intelligence, paleontology, biology, et cetera.., I am also uninterested in quibbling over labels. You want to call it evolutionary physiology? Have at it.

            “It is noted you elected to pass over the majority of the other information in my previous comment.”

            Your cynicism is neither warranted, nor appreciated. I didn’t find your observation that I mention both vaccines and antibiotics particularly useful to the topic (both are instances where ethical considerations can be complex). Your “brain teaser” about Polio is interesting, but mostly only pertains to history and is therefore a divergence from the present topic. This is not to say it’s not worth talking about, but that I neither have time, nor the obligation to address every one topic or question a commenter produces.

          • Ingemar Oseth

            Your definition of evolutionary psychology contains a paradigm that in many ways parallels the study of history. In their work historians use (borrow) the tools of many seemingly diverse professions as well. Interesting.

            I forgot to mention your earlier definition of anthropology is far too narrow.

            The Polio teaser was intended to test your response. I am disappointed to see that you admit no basis for a discussion of medical ethics and pass it off as “history.” After all you introduced the ethics of vaccinations.

            You do not have an obligation to discuss these topics with me although the very existence of your blog and comments section suggest something different. For this reason one can see how I came to be mistake your essay about medicine, antibiotics, and vaccinations to be an invitation for honest public discussion.

          • http://www.www.skepticink.com/incredulous Edward Clint

            It is history by definition. It’s also an interesting lead in to talk about medical ethics, just not the same talk as I initiated, which diminishes my immediate interest. If others commenters want to take you up on it, that’s absolutely fine and very much in keeping with the purpose of this space. I happen to choose not to at the moment, but if I have time I may come back to it later.

          • Ingemar Oseth

            “Your “brain teaser” about Polio is interesting, but mostly only pertains
            to history and is therefore a divergence from the present topic.”

            And,

            “It [Polio teaser] is history by definition. It’s also an interesting lead in to talk about medical ethics, just not
            the same talk as I initiated, which diminishes my immediate interest.”

            Returning to evolutionary medicine for a moment. I’m confused (A near constant state I admit.) Case Studies are based on “history”, and they are used extensively in the medical field. So are patient histories, statistical surveys, and the results of clinical trials.

            Here is my question. Are these things absent from the study of evolutionary medicine?

          • http://www.www.skepticink.com/incredulous Edward Clint

            Evolutionary -anything is largely based on understanding the past, though the mechanisms we discover that have operated in the past (natural selection) continue in the present and presumably the future.

            You mention several distinct meanings of “history” (though I meant only one particular meaning) but to answer you, no, they are certainly not absent from the study of evolutionary medicine.