On a beach run this morning I was listening to the Fresh Air interview with Jonah Lehrer, author of the book Imagine, which discusses how we get creative insights. Lehrer’s ideas about the nature of the creative process made me think about sickle cell anemia, and perhaps why a few cases of manic depression are the price of success for the human species. I know–weird linkage–but I will explain.
Lehrer describes how moments of insight happen when people are relaxed, when they are not trying (in the shower, staring at the clouds, etc). They often happen after people have done a lot of hard work or thinking, but when they have stopped trying or have given up on finding a solution. They are usually moments of openness and exhuberance (people in one study were most creative if they imagined themselves as seven year olds). But in order to turn those insights into something concrete, people have to turn back on the hard work and focus.
The first qualities–openness, optimism, energy, exhuberance–are common to states of hypomania. The second qualities–attention and focus, ability to work long and hard–are increased when people are told stories or shown pictures that make them a little sad or blue. Lehrer notes that Kay Redfield Jamieson and others have documented the relationship between manic depression and creativity, and says that this may be so because the swing between openness and energy on the one hand and focus and doggedness on the other recapitulates the creative process. But this works only if the swings aren’t too extreme. If someone has blatant mania, they are psychotic, believing things that are patently absurd (one manic real estate agent thought he could buy and sell whole countries). Frank depression is debilitating, even paralyzing, because the mind is focused intently only on the worst outcomes.
But if someone can swing between hypomania and very slightly anxiety, he or she may be able to have the best of these conditions without the biggest downsides. This kind of person may be much more creative and successful than his or her peers.
And this is where I think about malaria and sickle cell anemia. Malaria is a terrible disease that kills a large proportion of those infected, and is a chronic affliction for those it doesn’t. In areas of Africa where malaria is endemic, many people have a single copy of a gene that makes red blood cells resistant to the malaria parasite. This is a good thing. But if someone has two copies of the gene, their red blood cells can turn rigid and flip into a sickle shape that can clog small blood vessels, causing illness or even death. This is not a good thing. By the rules of genetics, though, most people in an area with endemic malaria will have one copy of the gene rather than two, leading to a net benefit for the population as a whole.
To me this looks like a nice model for genes that contribute to manic depression. If someone has none of these genes, they are likely to be unimaginative and complacent. The full complement of genes leads to frank bipolar illness and, often, early death by suicide or misadventure. But if these gene are floating around a population, most people will have only some of them, pushing the population as a whole to have those excited, open moments that characterize inspiration and the dogged, focused moments that result from light anxiety. There is no good animal model of bipolar illness, and the reason may be that it depends on genes that have been crucial to the unique imaginative qualities that make the human species more successful than all others.
