The trope of the tortured creative genius has persisted since Plato proposed banning poetry—long enough to seem like more than mere coincidence. From the emotionally unstable writer to the suicidal actor to the artist who cuts off his own ear, history is riddled with examples that bring the myth to life. But is there any science linking creativity output to madness? A new—and controversial—study concludes that indeed, creative genius and mental disorders are connected at a genetic level.

The new research, published in Nature Neuroscience, comes from Dr. Kári Stefánsson, a neurologist and CEO of a biological research company called deCODE Genetics. Stefánsson and his colleagues studied genetic data from more than 80,000 people in Iceland looking for genetic variants that increase the risk of bipolar disorder or schizophrenia. They then looked for those variants in 1000 “creative” people and found these people were 17 percent more likely to carry the variants for mental illness than noncreative types.

“The risk for schizophrenia is substantially higher in creative professions than in the average population in Iceland," Stefánsson told NPR.

The team then replicated these results looking at data from large studies carried out in Sweden and the Netherlands. In these findings, the variants for mental disorders were nearly 25 percent more common in creative people. "What we have shown is basically is that schizophrenia and creativity share biology," Stefánsson says.

Not so fast, some researchers are saying. “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. Indeed, the variants in the new study have a tiny, miniscule impact on creativity—less than 1 percent.

The study authors defined creative people as those working in an artistic profession or belonging to national artistic societies. But “belonging to an artistic society, or working in art or literature, does not prove a person is creative,” Albert Rothenberg, professor of psychiatry at Harvard University, tells the Guardian. “Many people who have mental illness do try to work in jobs that have to do with art and literature, not because they are good at it, but because they’re attracted to it. And that can skew the data.”

This isn't the first time researchers have found a link between creativity and madness. A 2012 study in the Journal of Psychiatric Research found that creative professionals are 8 percent more likely than the general population to be bipolar. Writers are especially vulnerable, the researchers say, being 120 percent more prone to suffer from bipolar disorder. Writers were also more likely to abuse substances and take their own lives. 

Another study also suggests creatives are more likely to have relatives with schizophrenia or bipolar disorder than the general public. But what’s the real connection between those characteristics? Is this about genes, or can it be chalked up to environmental influences? 

Yet another theory says creativity and mental illness share a process called “cognitive disinhibition,” or a failure to filter out all the useless information one encounters in the world. As Eric Jaffe at Co.Design explains it, “this failure may make schizotypal personalities more prone to delusional thoughts or mental confusion; on the flipside, it could make creative minds more fertile.”