[Paleopsych] Skeptic's Dictionary: Placebo Effect

Premise Checker checker at panix.com
Sat Oct 22 02:08:49 UTC 2005

Placebo Effect

    [5]Scientists See How Placebo Effect Eases Pain - Scientific American
    February 20, 2004

    [6]Power of the placebo: Simply expecting relief from pain can help,
    study shows, February 19, 2004

    [7]"Against Depression, a Sugar Pill Is Hard to Beat Placebos Improve
    Mood, Change Brain Chemistry in Majority of Trials of
    Antidepressants"  by Shankar Vedantam Washington Post
    vertline.gif (1078 bytes)

placebo effect

      "The physician's belief in the treatment and the patient's faith in
      the physician exert a mutually reinforcing effect; the result is a
      powerful remedy that is almost guaranteed to produce an improvement
      and sometimes a cure." -- Petr Skrabanek and James McCormick,
      Follies and Fallacies in Medicine, p. 13.

    The placebo effect is the measurable, observable, or felt improvement
    in health not attributable to treatment. This effect is believed by
    many people to be due to the placebo itself in some mysterious way. A
    placebo (Latin for I shall please) is a medication or treatment
    believed by the administrator of the treatment to be inert or
    innocuous. Placebos may be sugar pills or starch pills. Even fake
    surgery and fake psychotherapy are considered placebos.

    Researchers and medical doctors sometimes give placebos to patients.
    Anecdotal evidence for the placebo effect is garnered in this way.
    Those who believe there is scientific evidence for the placebo effect
    point to clinical studies, many of which use a [8]control group
    treated with a placebo. Why an inert substance, or a fake surgery or
    therapy, would be effective is not known.

               the psychological theory: it's all in your mind

    Some believe the placebo effect is psychological, due to a belief in
    the treatment or to a subjective feeling of improvement. Irving
    Kirsch, a psychologist at the University of Connecticut, believes that
    the effectiveness of Prozac and similar drugs may be attributed almost
    entirely to the placebo effect. He and Guy Sapirstein analyzed 19
    clinical trials of antidepressants and concluded that the expectation
    of improvement, not adjustments in brain chemistry, accounted for 75
    percent of the drugs' effectiveness ([9]Kirsch 1998).  "The critical
    factor," says Kirsch, "is our beliefs about what's going to happen to
    us. You don't have to rely on drugs to see profound transformation."
    In an earlier study, Sapirstein analyzed 39 studies, done between 1974
    and 1995, of depressed patients treated with drugs, psychotherapy, or
    a combination of both. He found that 50 percent of the drug effect is
    due to the placebo response.

    A person's beliefs and hopes about a treatment, combined with their
    suggestibility, may have a significant biochemical effect. Sensory
    experience and thoughts can affect neurochemistry. The body's
    neurochemical system affects and is affected by other biochemical
    systems, including the hormonal and immune systems. Thus, it is
    consistent with current knowledge that a person's hopeful attitude and
    beliefs may be very important to their physical well-being and
    recovery from injury or illness.

    However, it may be that much of the placebo effect is not a matter of
    mind over molecules, but of mind over behavior. A part of the behavior
    of a "sick" person is learned. So is part of the behavior of a person
    in pain. In short, there is a certain amount of role-playing by ill or
    hurt people. Role-playing is not the same as faking or malingering.
    The behavior of sick or injured persons is socially and culturally
    based to some extent. The placebo effect may be a measurement of
    changed behavior affected by a belief in the treatment. The changed
    behavior includes a change in attitude, in what one says about how one
    feels, and how one acts. It may also affect one's body chemistry.

    The psychological explanation seems to be the one most commonly
    believed. Perhaps this is why many people are dismayed when they are
    told that the effective drug they are taking is a placebo. This makes
    them think that their problem is "all in their mind" and that there is
    really nothing wrong with them. Yet, there are too many studies which
    have found objective improvements in health from placebos to support
    the notion that the placebo effect is entirely psychological.

      Doctors in one study successfully eliminated warts by painting them
      with a brightly colored, inert dye and promising patients the warts
      would be gone when the color wore off. In a study of asthmatics,
      researchers found that they could produce dilation of the airways
      by simply telling people they were inhaling a bronchiodilator, even
      when they weren't. Patients suffering pain after wisdom-tooth
      extraction got just as much relief from a fake application of
      ultrasound as from a real one, so long as both patient and
      therapist thought the machine was on. Fifty-two percent of the
      colitis patients treated with placebo in 11 different trials
      reported feeling better -- and 50 percent of the inflamed
      intestines actually looked better when assessed with a
      sigmoidoscope ("The Placebo Prescription" by Margaret Talbot, New
      York Times Magazine, January 9, 2000).[10]*

    It is unlikely that such effects are purely psychological. But it is
    not necessarily the case that the placebo is actually effective in
    such cases.

                     the nature-taking-its-course theory

    Some believe that at least part of the placebo effect is due to an
    illness or injury taking its natural course. We often heal
    spontaneously if we do nothing at all to treat an illness or injury.
    Furthermore, many disorders, pains and illnesses, wax and wane. What
    is measured as the placebo effect could be, in many cases, the
    measurement of natural [11]regression. In short, the placebo may be
    given credit that is due to nature.

    However, spontaneous healing and spontaneous remission of disease
    cannot explain all the healing or improvement that takes place because
    of placebos. People who are given no treatment at all often do not do
    as well as those given placebos or real medicine and treatment.

                       the process-of-treatment theory

    Another theory gaining popularity is that a process of treatment that
    involves showing attention, care, affection, etc., to the
    patient/subject, a process that is encouraging and hopeful, may itself
    trigger physical reactions in the body which promote healing.
    According to Dr. Walter A. Brown, a psychiatrist at Brown University,

      there is certainly data that suggest that just being in the healing
      situation accomplishes something. Depressed patients who are merely
      put on a waiting list for treatment do not do as well as those
      given placebos. And -- this is very telling, I think -- when
      placebos are given for pain management, the course of pain relief
      follows what you would get with an active drug. The peak relief
      comes about an hour after it's administered, as it does with the
      real drug, and so on. If placebo analgesia was the equivalent of
      giving nothing, you'd expect a more random pattern ("The Placebo
      Prescription" by Margaret Talbot, New York Times Magazine, January
      9, 2000).[12]*

    Dr. Brown and others believe that the placebo effect is mainly or
    purely physical and due to physical changes which promote healing or
    feeling better. It is assumed that the physical changes are not caused
    by the placebo itself. So, what is the explanatory mechanism for the
    placebo effect? Some think it is the process of administering it. It
    is thought that the touching, the caring, the attention, and other
    interpersonal communication that is part of the controlled study
    process (or the therapeutic setting), along with the hopefulness and
    encouragement provided by the experimenter/healer, affect the mood of
    the subject, which in turn triggers physical changes such as release
    of endorphins. The process reduces stress by providing hope or
    reducing uncertainty about what treatment to take or what the outcome
    will be. The reduction in stress prevents or slows down further
    harmful physical changes from occurring.

    The process-of-treatment hypothesis would explain how inert
    [13]homeopathic remedies and the questionable therapies of many
    "alternative" health practitioners are often effective or thought to
    be effective. It would also explain why pills or procedures used by
    conventional medicine work until they are shown to be worthless.

      Forty years ago, a young Seattle cardiologist named Leonard Cobb
      conducted a unique trial of a procedure then commonly used for
      angina, in which doctors made small incisions in the chest and tied
      knots in two arteries to try to increase blood flow to the heart.
      It was a popular technique -- 90 percent of patients reported that
      it helped -- but when Cobb compared it with placebo surgery in
      which he made incisions but did not tie off the arteries, the sham
      operations proved just as successful. The procedure, known as
      internal mammary ligation, was soon abandoned ("The Placebo
      Prescription" by Margaret Talbot, New York Times Magazine, January
      9, 2000).[14]*

    Of course, spontaneous healing or [15]regression can also adequately
    explain why homeopathic remedies might appear to be effective. Whether
    the placebo effect is mainly psychological, misunderstood spontaneous
    healing, due to showing care and attention, or due to some combination
    of all three may not be known with complete confidence.

                       the powerful placebo challenged

    The powerful effect of the placebo is not in doubt. [16]It should be,
    however, according to Danish researchers Asbjørn Hróbjartsson and
    Peter C. Götzsche. Their meta-study of 114 studies involving placebos
    found "little evidence in general that placebos had powerful clinical
    effects...[and]...compared with no treatment, placebo had no
    significant effect on binary outcomes, regardless of whether these
    outcomes were subjective or objective. For the trials with continuous
    outcomes, placebo had a beneficial effect, but the effect decreased
    with increasing sample size, indicating a possible bias related to the
    effects of small trials ("Is the Placebo Powerless? An Analysis of
    Clinical Trials Comparing Placebo with No Treatment," The New England
    Journal of Medicine, May 24, 2001 (Vol. 344, No. 21)."

    According to Dr. Hróbjartsson, professor of medical philosophy and
    research methodology at University of Copenhagen, "The high levels of
    placebo effect which have been repeatedly reported in many articles,
    in our mind are the result of flawed research methodology."[17]* This
    claim flies in the face of more than fifty years of research. At the
    very least, we can expect to see more rigorously designed research
    projects trying to disprove Hróbjartsson and Götzsche.

                            the origin of the idea

    The idea of the powerful placebo in modern times originated with H. K.
    Beecher. He evaluated over two dozen studies and calculated that about
    one-third of those in the studies improved due to the placebo effect
    ("The Powerful Placebo," 1955). Other studies calculate the placebo
    effect as being even greater than Beecher claimed. For example,
    studies have shown that placebos are effective in 50 or 60 percent of
    subjects with certain conditions, e.g., "pain, depression, some heart
    ailments, gastric ulcers and other stomach complaints."[18]* And, as
    effective as the new psychotropic drugs seem to be in the treatment of
    various brain disorders, [19]some researchers maintain that there is
    not adequate evidence from studies to prove that the new drugs are
    more effective than placebos.

    Placebos have even been shown to cause unpleasant side effects.
    Dermatitis medicamentosa and angioneurotic edema have resulted from
    placebo therapy, according to [20]Dodes. There are even reports of
    people becoming [21]addicted to placebos.

                             the ethical dilemma

    The power of the placebo effect has led to an ethical dilemma. One
    should not deceive other people, but one should relieve the pain and
    suffering of one's patients. Should one use deception to benefit one's
    patients? Is it unethical for a doctor to knowingly prescribe a
    placebo without informing the patient? If informing the patient
    reduces the effectiveness of the placebo, is some sort of deception
    warranted in order to benefit the patient? Some doctors think it is
    justified to use a placebo in those types of cases where a strong
    placebo effect has been shown and where distress is an aggravating
    factor.[22]*  Others think it is always wrong to deceive the patient
    and that informed consent requires that the patient be told that a
    treatment is a placebo treatment. Others, especially "alternative"
    medicine practitioners, don't even want to know whether a treatment is
    a placebo or not. Their attitude is that as long as the treatment is
    effective, who cares if it a placebo? Of course, if the placebo effect
    is an illusion, then another ethical dilemma arises: should placebos
    be given if it is known that deception does not really reduce pain or
    aid in the cure of anything?

                           are placebos dangerous?

    While skeptics may reject faith, prayer and "alternative" medical
    practices such as [23]bioharmonics, [24]chiropractic and
    [25]homeopathy, such practices may not be without their salutary
    effects. Clearly, they can't cure cancer or repair a punctured lung,
    and they might not even prolong life by giving hope and relieving
    distress as is sometimes thought. But administering useless therapies
    does involve interacting with the patient in a caring, attentive way,
    and this can provide some measure of comfort. However, to those who
    say "what difference does it make why something works, as long as it
    seems to work" I reply that it is likely that there is something which
    works even better, something for the other two-thirds or one-half of
    humanity who, for whatever reason, cannot be cured or helped by
    placebos or spontaneous healing or natural regression of their pain.
    Furthermore, placebos may not always be beneficial or harmless. In
    addition to adverse side effects, mentioned above, John Dodes notes

      Patients can become dependent on nonscientific practitioners who
      employ placebo therapies. Such patients may be led to believe
      they're suffering from imagined "reactive" hypoglycemia,
      nonexistent allergies and yeast infections, dental filling amalgam
      "toxicity," or that they're under the power of Qi or
      extraterrestrials. And patients can be led to believe that diseases
      are only amenable to a specific type of treatment from a specific
      ([26]The Mysterious Placebo by John E. Dodes, Skeptical Inquirer,
      Jan/Feb 1997).

    In other words, the placebo can be an open door to quackery.

    See also [27]confirmation bias, [28]control study, [29]communal
    reinforcement, [30]magical thinking, [31]nocebo, [32]Occam's razor,
    [33]post hoc fallacy, [34]regressive fallacy, [35]selective thinking,
    [36]self-deception, [37]subjective validation,[38] testimonials, and
    [39]wishful thinking.

    For examples of beliefs deeply affected by the placebo effect see the

      [41]"alternative" health practices
      [44]crystal power
      [45]homeopathy and

    [47]further reading
      * [48]The Mysterious Placebo by John E. Dodes
      * [49]The placebo effect is the healing force of nature by G.
      * [50]The Mysterious Placebo Effect by Carol Hart Modern Drug
        Discovery July/August 1999
      * Kirsch, Irving , Ph.D. and Guy Sapirstein, Ph.D. [51]"Listening to
        Prozac but Hearing Placebo: A Meta-Analysis of Antidepressant
        Medication"  Prevention & Treatment, Volume 1, June 1998.
      * [52]The Placebo Prescription - New York Times Magazine 1/09/2000
      * [53]Sham Surgery Returns as a Research Tool by Sheryl Gay
        Stolberg, New York Times 4/25/1999
      * [54]"Placebo Effect Accounts For Fifty Percent Of Improvement In
        Depressed Patients Taking Antidepressants" by the American
        Psychological Association
      * [55]"Placebo Effects Prove the Value of Suggestion" by Charles
        Henderson, Ph.D. (Interesting experiment on subliminal
      * [56]Is Prescribing Placebos Ethical? experts argue the pros and

    [57]Engel, Linda W. et al. The Science of the Placebo - Toward an
    Interdisciplinary Research Agenda ( BMJ Books, 2002).

    [58]Fisher, Seymour and Roger P. Greenberg. eds. From Placebo to
    Panacea: Putting Psychiatric Drugs to the Test (John Wiley and Sons,

    Hróbjartsson, Asbøjrn and Peter C. Götzsche. "Is the Placebo
    Powerless? An Analysis of Clinical Trials Comparing Placebo with No
    Treatment," The New England Journal of Medicine, May 24, 2001 (Vol.
    344, No. 21).

    [59]Harrington, Anne. ed. The Placebo Effect : An Interdisciplinary
    Exploration (Harvard University Press, 1999).

    Hartwick, Joseph J. Placebo Effects in health and Disease: Index of
    new Information with Authors, Subjects, and References (Washington,
    D.C.: ABBE Publications Association, 1996).

    [60]Jerome, Lawrence E. Crystal Power - The Ultimate Placebo Effect
    (Amherst, NY: Prometheus, 1996).
    [61]Skrabanek, Petr, Ph.D. and James McCormick, M.D. (1990). Follies &
    Fallacies in Medicine. Prometheus.

    [62]Ogelsby, Dr. Paul. The Caring Physician : The Life of Dr. Francis
    W. Peabody (Harvard University Press, 1991).

    [63]Shapiro, Arthur K. and Elaine. The Powerful Placebo: From Ancient
    Priest to Modern Physician (Johns Hopkins University Press, 1997).

    [64]Stanovich, Keith E. How to Think Straight About Psychology, 3rd
    ed., (New York: Harper Collins, 1992).

    Sternberg, Esther M. and Philip W. Gold. "The Mind-Body Interaction in
    Disease," Scientific American," special issue "Mysteries of the Mind,"
    (January 1997).

    [65]White, Leonard, Bernard Tursky and Gary Schwartz. Placebo: Theory
    Research, and Mechanisms, ed.  (New York: Guilford Press, 1985).
    ©copyright 2005
    Robert Todd Carroll

    [66]larrow.gif (1051 bytes) pious fraud
    [67]plant perception[68]  rarrow.gif (1048 bytes)


    6. http://www.cnn.com/2004/HEALTH/02/19/brain.power.ap/
    7. http://www.washingtonpost.com/wp-dyn/articles/A42930-2002May6.html
    8. http://skepdic.com/control.html
    9. http://journals.apa.org/prevention/volume1/pre0010002a.html
   10. http://www.nytimes.com/library/magazine/home/20000109mag-talbot7.html
   11. http://skepdic.com/regressive.html
   12. http://www.nytimes.com/library/magazine/home/20000109mag-talbot7.html
   13. http://skepdic.com/homeo.html
   14. http://www.nytimes.com/library/magazine/home/20000109mag-talbot7.html
   15. http://skepdic.com/regressive.html
   16. http://skepdic.com/refuge/funk21.html#placebo
   17. http://search.intelihealth.com/IH/ihtIH?d=dmtICNNews&c=322238&p=
   18. http://www.nytimes.com/library/magazine/home/20000109mag-talbot7.html
   19. http://www.amazon.com/exec/obidos/ISBN=0471148482/roberttoddcarrolA/
   20. http://www.csicop.org/si/9701/placebo.html
   21. http://home.comcast.net/~bkrentzman/meds/placebo.html
   22. http://www.nytimes.com/library/magazine/home/20000109mag-talbot7.html
   23. http://skepdic.com/bioharmonics.html
   24. http://skepdic.com/chiro.html
   25. http://skepdic.com/homeo.html
   26. http://www.csicop.org/si/9701/placebo.html
   27. http://skepdic.com/confirmbias.html
   28. http://skepdic.com/control.html
   29. http://skepdic.com/comreinf.html
   30. http://skepdic.com/magicalthinking.html
   31. http://skepdic.com/nocebo.html
   32. http://skepdic.com/occam.html
   33. http://skepdic.com/posthoc.html
   34. http://skepdic.com/regressive.html
   35. http://skepdic.com/selectiv.html
   36. http://skepdic.com/selfdeception.html
   37. http://skepdic.com/subjectivevalidation.html
   38. http://skepdic.com/testimon.html
   39. http://skepdic.com/wishfulthinking.html
   40. http://skepdic.com/acupunc.html
   41. http://skepdic.com/althelth.html
   42. http://skepdic.com/aroma.html
   43. http://skepdic.com/bioharmonics.html
   44. http://skepdic.com/crystals.html
   45. http://skepdic.com/homeo.html
   46. http://skepdic.com/reflex.html
   47. http://www.amazon.com/exec/obidos/ISBN=0471272426/roberttoddcarrolA/
   48. http://www.csicop.org/si/9701/placebo.html
   49. http://www.tribunes.com/tribune/edito/8-2z.htm
   50. http://www.pubs.acs.org/hotartcl/mdd/99/aug/mysterious.html
   51. http://journals.apa.org/prevention/volume1/pre0010002a.html
   52. http://www.nytimes.com/library/magazine/home/20000109mag-talbot7.html
   53. http://www.nytimes.com/library/review/042599surgery-ethics-review.html
   54. http://www.antidepressantsfacts.com/1996-APA-placebo-vs-SSRI.htm
   55. http://www.bcx.net/hypnosis/placebo.htm
   56. http://www.acsh.org/healthissues/newsID.678/healthissue_detail.asp
   58. http://www.amazon.com/exec/obidos/ISBN=0471148482/roberttoddcarrolA/
   59. http://www.amazon.com/exec/obidos/ISBN=067466986X/roberttoddcarrolA/
   60. http://www.amazon.com/exec/obidos/ISBN=0879755326/roberttoddcarrolA/
   61. http://www.amazon.com/exec/obidos/ISBN=0879756306/roberttoddcarrolA/
   62. http://www.amazon.com/exec/obidos/ISBN=0674097386/roberttoddcarrolA/
   63. http://www.amazon.com/exec/obidos/ISBN=0801855691/roberttoddcarrolA/
   64. http://www.amazon.com/exec/obidos/ISBN=0321012461/roberttoddcarrolA/
   65. http://www.amazon.com/exec/obidos/ISBN=0898626498/roberttoddcarrolA/
   66. http://skepdic.com/piousfraud.html
   67. http://skepdic.com/plants.html

More information about the paleopsych mailing list