Sunday, 11 March 2007

Causal complexity

Another piece of research pointing to the link between depression and a major illness. This time it's about the joint effect of depression and Type 2 diabetes on heart disease. Each factor is known to increase the risk of heart disease, but they act more potently together. Of course, extracting a causal picture from all this is very difficult. Depression is known to increase insulin resistance. One might propose, then, that there's a particular danger for the heart from depression-induced diabetes.

But one can think up any number of ways in which the interaction may occur. A common style of hypothesising is exemplified by the researcher Anastasia Georgiades herself:
"Patients with type 2 diabetes typically have an extensive self-care regimen involving special diet, medications, exercise and numerous appointments with their doctor," she said. "It may be that such patients who are depressed might not be as motivated to carry out all these activities, thereby putting them at higher risk."
But even if you could show that the more depressed take less care of themselves, after what I discussed in the last post, how do we know that an effect on the heart isn't also produced by the depressed patient's lack of faith in medicine, or reduced will to live? We can't exclude the need to use this kind of language.

Then there's the matter of how placebos can effect depression. Here is a report of research which suggests brain-scanning can tell the difference between placebo-induced and medication-induced relief. Andrew Leuchter of UCLA remarks:
"Medications are effective, but there may be other ways to help people get better. If we can identify what some of the mechanisms are that help people get better with placebo, we may be able to make treatments more effective."
Interestingly he uses language referring to the subjectivity of the patients:
"...they made a decision to come in for treatment," he said. "They were prepared to get well. They came in, they actually got engaged with somebody. They started talking with staff, with nurses, with the physician. They got a lot of extra attention."
If the global warming debate involves extremely intricate causal mechanisms, there's no reason to expect any less intricacy in the case of human health. And perhaps with the necessity to talk about patients' subjectivity, this latter case is in a sense more difficult.

1 comment:

Tony said...

The placebo and Roseto effects are related. Community i.e. mutual support system, helps deflect illness by creating sense of safety. Those who fall ill don't feel safe (connected to the rest of society). Placebo's work, nt because the doctor believes they'll work but because the patient believes sombody else externally, cares. Munchausen By Proxy, is a form of hypochondria in that it too is a cry for attention. In both these cases the sufferer is debilitated in their attempt to ask for help - in other words they are demanding attention but neither can ask directly, so use subterfuge to get what they want - much as a rapist is totally inappropriate in their attempt to get sex.

As with Harry Harlow's experiments with wire monkey mothers, deprived infants are incapable of reacting normally in social situations ever again as are the autistic but for different developmental reasons.

Illness is in my opinion, the mind or body trying to put right/adjust what is wrong in its world by temporarily decommisioning itself much as a car has to be taken off the road to be repaired, rather than continue to be run, further worsening the problem it has. The collapse of internal community, like that of external community, means behaviour that is erratic and disconnected and bodily functions too that are broken or, too fast or too slow, for optimum performance.