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Role of Instrumentation / Philosophy of Science

  1. Aug 9, 2007 #1
    I'm trying to explain something to someone, but I can't find the right words; I hope some of you can help me.

    Observations are limited by the instruments available to a scientist. For example, before invention of the microscope, observation of microscopic objects was impossible.

    In the medical sciences, instrument-limitations plays a significant role. For example, x-rays have limited precision, because beaming too much energy into a patient does more harm than good. And you can't go around cutting every patient open to see what's inside, for obvious reasons.

    The precision of instruments, while constantly improving, will always be limited.

    In the field of Medicine, mental disorder is defined officially by the American Psychiatric Association's DSM-IV-TR. Page 485 defines Somatoform Disorder:

    The APA is saying that a patient has Somatoform Disorder whenever she has symptoms, but doctors are unable to explain why.

    I find this concept of mental-disorder to be absurd, because it discounts the possibility that a patient is suffering from a general medical condition (e.g., an infectious disease), but the general medical condition is not detectable by the instruments available to the physician.

    The history of peptic-ulcer-disease confirms the absurdity of this definition of mental-disorder. For decades, researches found no infectious-disease responsible for ulcers; and so for decades, doctors told patients their illness was mental, due to stress. -- http://www.cdc.gov/ulcer/history.htm

    Peter Moran, one of the researchers involved, recounts,

    I take issue with the APA's definition of mental disorder, because it discounts the role of doctor and his instruments. If a patient truly is suffering from infectious-disease, but the doctor and his limited instruments fail to identify the infection; the patient is diagnosed as mentally disordered, as advised by the APA.

    My goal is to describe the absurdity of the DSM's definition of mental-disorder, but using fewer words than I've used here. Any advice or ideas?

  2. jcsd
  3. Aug 9, 2007 #2


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    In medicine it's not the limitation of the instruments so much as the limitation of the understadning of the system - especially the brain.
    Even if you could image the brain at the individual molecule level ( which you almost can for small areas ) and can already detect chemicals at pretty much single molecule concentrations that wouldn't tell you if the patient was mad.
  4. Aug 9, 2007 #3

    Claude Bile

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    I agree with mgb_phys. Mental disorders are due to faulty "wiring" in the brain, and not necessarily due to a pathogen, or even a physical condition. Since we haven't even scratched the surface of how the brain functions, even if we had a perfect picture of the whole brain, we wouldn't be able to tell if someone was healthy or chronically depressed.

    It's like seeing if a piece of software is faulty or not in a PC by looking at a bunch of 1's and 0's, without knowing the software architecture of that particular PC.

    Even perfect imaging instruments won't be able to diagnose a mental disorder until we figure out how the brain works.

  5. Aug 9, 2007 #4
    I appreciate the point you two are making; but I still find fault in the medical establishment's practice: In an infectious-disease textbook, you would never find a passage saying "Test the patient for various mental disorders, and if all tests come back negative, diagnose him with this infectious disease." But that form of definition is what the APA uses to define Somatoform Disorder.

    As a result of this biased way of defining diseases, doctors have misdiagnosed millions of patients as mentally disordered, when in hindsight the patients have turned out to be suffering from organic illness. Examples include:

    thyroid disease
    lyme disease
    Gulf-War Illness

    On the other hand, the number of patients with mental illness who've been misdiagnosed as having organic illnesses is, I'm guestimating, close to zero. I doubt that such a bias is what's best for anyone.

    I'd appreciate any further thoughts anyone here has. I'm sorry that this isn't about physics, but physicists are a smarter bunch than doctors, IMHO, so I thought I'd ask here. My own training is in cognitive science, but it's been a while since I was active in that field.
  6. Aug 9, 2007 #5


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    As a physicist I could arrogantly assume that the doctors reasoning goes something like "There are lots of infectious and chemical diseases, it would be difficult to learn, understand and test for them all and involve lots of tedious lab work - however deciding he has some random mental condition means I can be on the golf course by 5:00"

    Of course since physicists are never arrogant (unlike doctors) I'm sure that can't be true. Having known medical students I have never been deeply impressed with their knowledge of chemistry, experimental methods or ability to follow a logical arguement.
  7. Aug 11, 2007 #6
    I read you loud and clear.
  8. Oct 7, 2007 #7
    I worked some years for a group of neurologists and associated specialists. In general, they are very diagnosis/treatment oriented. They have a professional inclination toward QUICKLY (welcome to 3rd party reimbursement medicine) making a codable diagnosis and making an appropriate treatment plan. Patients also generally expect something to be diagnosed and treated (thank God for low dosage Vallium). The physicians are quite constrained by the hospital, liability insurance, FDA, NIH, the insurance companies, and the pharmaceutical industry (and probably others). I suspect there will always be "wastebasket" illnesses unless we are able to move away from the medical coding model currently in place in the US.

    A good way to think about physicians, in my opinion, is that they also make good engineers - very solution oriented.
  9. Oct 7, 2007 #8


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    Except I've never seen a doctor say in front of a patient, "I'll just check that in a book" where as I would be very nervous of an engineer who said "I know the maximum load in that component - I don't need to check any tables"
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