Map of life expectancy at birth from Global Education Project.

Thursday, May 25, 2006

The Nosology Knows

Before I get to the promised post on the Age of Psychopharmacology, I want to talk a bit about the concept of disease. What I will say here is not at all original.

Nosology means the classification of diseases. Currently, the world uses a system called the International Classification of Diseases-10, or ICD-10. Here's how it begins:

Cholera due to Vibrio cholerae 01, biovar cholerae

Classical cholera
Cholera due to Vibrio cholerae 01, biovar eltor

Cholera eltor
Cholera, unspecified

Typhoid and paratyphoid fevers
Typhoid fever

Infection due to Salmonella typhi
Paratyphoid fever A
Paratyphoid fever B
Paratyphoid fever C
Paratyphoid fever, unspecified

Infection due to Salmonella paratyphi NOS

And so on. As you can well imagine, by the time we get to
Sequelae of complications of surgical and medical care, not elsewhere classified
we've seen one hell of a lot of diseases.

The mental disorders (ICD-10 F00-F99) are also catalogued separately in the Diagnostic and Statistical Manual of Mental Disorders-IV(TR), which includes the criteria for declaring that somebody has, let us say, "Involutional melancholia, single episode or unspecified," as opposed to "Monopolar depression, single episode or unspecified."

In order to do any doctoring, the physician must first make a diagnosis, which means applying to you one of these thousands of labels. People have recognized entities that seem a lot like what we today call "diseases" since biblical times. For example, there is the Diagnostic and Statistical Manual of Skin Diseases in Leviticus 13, which goes on for many pages in this vein (New International Version):

18 "When someone has a boil on his skin and it heals, 19 and in the place where the boil was, a white swelling or reddish-white spot appears, he must present himself to the priest. 20 The priest is to examine it, and if it appears to be more than skin deep and the hair in it has turned white, the priest shall pronounce him unclean. It is an infectious skin disease that has broken out where the boil was. 21 But if, when the priest examines it, there is no white hair in it and it is not more than skin deep and has faded, then the priest is to put him in isolation for seven days. 22 If it is spreading in the skin, the priest shall pronounce him unclean; it is infectious. [Traditionally translated a "a leprosy." Obviously at the time this was written no word for "infectious" existed because nobody knew what infection was -- Cervantes] 23 But if the spot is unchanged and has not spread, it is only a scar from the boil, and the priest shall pronounce him clean.

With no really meaningful exceptions, the classification of diseases -- the fancy word for which is nosology -- continued on the same basis into the 20th Century. Diseases were defined by clusters of signs -- symptoms. Nowadays, however, whenever they can doctors take the symptoms only as a starting point. They are much happier when they can define diseases in terms of an underlying process. In the old days, the disease might have been a "sore throat," but today there are many different sore throats. Instead, it might be "Staphylococcus aureus infection," which more specifically means that a particular species of microorganism is feeding on, and reproducing within, the victim's body. Knowing that, we know the cure: feed the person an antibiotic.

There are many, some of whom operate outside of the epistemological framework of allopathic medicine (the fancy name for the standard kind of medicine that is taught at Harvard, the historical origins of which we can get into later if anybody cares), some of whom are within it or don't promote any particular alternative, who criticize the reductionism of medical diagnosis and treatment. The microbe is ubiquitous, but it's only causing disease in this particular individual. The person is not a collection of tissues and whatever happens to be living in them, but a complete system, that can't be understood by adding up its subunits. This person might have gotten sick because of being debilitated by the wrong diet, not enough sleep, too much alcohol, or some other set of interacting processes, which in turn might be related to social marginalization due to racial prejudice or odd behavior or the sequelae of a traumatic experience . . . In other words, while the biological system cannot be properly understood in reductionist terms, even that system is not self-contained but is part of a bio-psychic system which is in turn part of a bio-psycho-social system.

You get the idea. The reductionist approach to medicine is pretty successful at fixing the immediate problem, but seems to fall short when it comes to promoting health and preventing disease. On the one hand, maybe doctors could accomplish more if they started to pay more attention to our diets, our exercise and sleeping habits, even our social lives and how we relate to other people.

But wait a minute -- I don't want my doctor trying to run my life, and I don't want the medical profession turning every problem into a medical problem. It seems we have a paradox.

I'll take this discussion into the realm of mental "health" (whatever that means) next.

1 comment:

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