The function of mental illness

In the final tally, it’s easier to understand the physiology of disease than it is to arrive at a clear-eyed view of what disease means. This is all the more true of mental diseases, where the symptoms are less overt and often less clear-cut, and hence where the promise of imposing order through a physiology of the mind is all the more seductive. We strive to give mental illness a meaning by giving it a biological meaning, by showing that it has some adaptive function. Oftentimes this is an attempt to see behind one’s illness the workings of a higher power: you treat excessive melancholy as a kind of finely-tuned sensory power–the fact that you are so sad is supposed to tell you something about your larger situation, for example that you have some pressing problem you need to withdraw from the world in order to analyze. This may well be true, but even if it is what does it mean? It can perhaps interrupt a spiral of self-loathing where the depressed feels even worse for being on top of it all a malfunctioning member of the species. But this isn’t really to give depression a meaning. At most it clears away one of the illusory meanings, spiritual-cum-biological pollution, that has historically been attached to it. Whether excessive melancholy is good or bad is not settled by biology. We could recognize its burdens even when our science was still primitive. Similarly, the ultimate accounting of the costs and benefits of melancholy in its more moderate forms cannot be reckoned in biological terms.