The genetic underpinnings of psychosis are elusive and diffuse. There are hundreds of common genetic mutations scattered throughout the human genome that each bump up by just a tiny bit the risk of developing a mental illness like schizophrenia. Many people carry some set of those genes, but most don't end up with a psychotic disorder. Instead, a study suggests, they might be getting a small creative boost.
Those genetic changes may persist in human DNA because they confer benefits, according Dr. Kári Stefánsson, a neurologist and CEO of a biological research company called deCODE Genetics, which conducted the study published in Nature Neuroscience Monday.
"They are found in most of us, and they're common because they either confer or in the past conferred some reproductive advantage," he says. The advantage of having a more creative mind, he suggests, might help explain why these genes persist, even as they increase the risk of developing debilitating disorders, such as schizophrenia.
Aristotle on the roots of "madness"
It's an idea from the ancients. The philosopher Aristotle famously opined that genius and madness go hand in hand. Psychiatric studies have to some degree supported the adage. Studies of over a million Swedish people in 2011 and 2013 found that people who had close relatives with schizophrenia or bipolar disorder were much more likely to become creative professionals. (The patients with mental illness were not themselves more creative, with the exception of some who had bipolar disorder.)
What's more, studies that looked at healthy people who carry genetic markers associated with a psychotic disorder found their brains work slightly differently than others who lack those genetic markers.
"They were small [differences] but you could kind of see, gee, if you add a bunch of these up it could add up to something important," says Dr. Ray DePaulo, Jr., a psychiatrist at Johns Hopkins University School of Medicine. "Something" like schizophrenia or bipolar disorder or, as Stefánsson thinks, a creative disposition.
Stefánsson and his colleagues studied the genes of more than 80,000 Icelanders to see if writers, dancers, artists, actors or musicians had genetic markers that were associated with an added risk for certain psychiatric disorders.
"And, indeed, the risk for schizophrenia is substantially higher in creative professions than in the average population in Iceland," he says. If people are getting at least some of their creative impulse from these genes, Stefánsson says, then "the variance in the genome that leads to creativity also leads to schizophrenia."
Not so fast, other scientists say
Other researchers are cautious about making that claim. "Any particular set of genes is only going to explain a very small part of variation in any psychological trait," says Scott Barry Kaufman, a psychologist at the University of Pennsylvania. He says there are so many more things that determine whether or not someone is going to have schizophrenia or be creative — "things like what you have going on in your life, your environment, etc."
And the apparent genetic effect in Stefánsson's study, while statistically significant, is minute. In essence, these genes have less than a 1 percent effect on creativity. That's not quite enough to say for sure if there's a strong connection between genetics and creativity, or if it means that creativity came at the price of schizophrenia.
"It's a hint ... it may be worthy of note," DePaulo says, with an ambiguous groan. "But eh, it's no cigar. In horseshoes, it's not a horseshoe."
Genes can't be the only answer
Stefánsson stand by his hypothesis, though. He thinks genes must be influencing creative minds in a substantial way. But, he admits, they can't be the sole source of creativity in a human being. "I'm convinced [these genes] are not a major contributor to the creativity in all of us," he says. "But they exist ... with fairly high frequency."
Kay Redfield Jamison, a clinical psychologist at Johns Hopkins University School of Medicine and author of "Touched with Fire: Manic Depressive Illness and the Artistic Temperament," agrees with Stefánsson.
"[The paper] shows ... not just a vague psychological connection between mental illness and creative thinking, but also something very fundamental," she says, and the implications for that run deep. "If you can figure out what these genes are, can you make people not be creative?"
But there are so many components to creativity that this can't be the only answer.
"It's not going to be anything terribly simple," Redfield Jamison says. "And why would it be?" After all, she adds, if there were a singular source of inspiration, then there probably wouldn't be a lot of original work.