We had a lecture today on the genetics and ethics of mental illness. Mostly it was about informed consent, eugenics, and genomic medicine. But I was disturbed by two things in the philosophy of medicine assumed.
There is a relativistic view of health and illness in medicine. It seems especially difficult to avoid in psychiatry. In this view, "health" and "disease" are on a sort of spectrum, and people are somewhere on the spectrum. On this spectrum, it's somewhat arbitrary what is "healthy" and what is not. The border between loose connective tissue and dense irregular connective tissue in the dermis is somewhat arbitrary--it's more like a gradient, but the professor always draws a line across the picture somewhere. Similarly, the clinician or laboratory or government agency decides what "healthy" is, and what "diseased" is.
It's very easy to think this, because our imaginations lend a lot of credence to it. But it's not true. Health and sickness are like virtue and vice or water and oil: immiscible. A healthy person is like a glass of water; a sick person is like a cup of oil. Granted, there are lots of kinds of oil, and some are less viscous than others and resemble water much more. (The analogy limps because a sick person can become healthy and vis a versa; last time I checked the literature, a cup of water cannot become a cup of oil.)
Another problem was the blatant assumption that disease is largely determined by culture. The lecturer quoted the subtraction of homosexuality from the DSM as an example. (In 1973, demonstrations and protests pressured the American Psychiatric Association to review the literature and vote on the diagnosis.) This is indeed an example of a culture determining what is called a disease. It is not an example of a culture determining what is a disease.
What is and is not a disease is not determined by any person or any culture. It is determined by the nature of man (the internal principle of motion). For instance: a mechanic determines whether or not a car is broken based on the car's intended function. He does not consult the cultural norms for what is accepted; he does not vote with his fellow mechanics about it. Similarly, physicians ought not to consult the cultural norms when they identify disease states, nor ought they to vote among themselves. The should consult man's nature and determine whether a state is compatible with man's natural (intended) function.
(As an aside: homosexuality doesn't take much thought if considered this way. Man is male and female by nature, and designed for heterosexual union.)
What was the APA considering in 1973? Previous to this lecture, I did not know. Now, I do: the qualification for mental disease is inability to function in life. (The lecturer cited an example to drive this point home: if a person presents with classical schizoprenia--hallucinations, delusions, genetic predispositions, the works--but can function normally, they don't have it. According to this speaker, most of the DSM entries are now modified with this criterion: the patient must be dysfunctional according to generally accepted norms.) Gays, the APA said in '73, were able to function and felt quite accepted and normal. Therefore, they were not mentally diseased.
There is no nature in psychiatry, and I fear there is little more in medicine.