In 2009, researchers at Hungary's Semmelweis University published new findings about a relatively seldom-studied gene called neuregulin 1. To that point known almost solely as a gene that increased one's susceptibility to schizophrenia, neuregulin 1 belonged to the study of madness.
What the Semmelweis researchers did, however, was connect the gene not just to madness, but to genius as well.
Confirming Aristotle's immortal yet disputed quotation stating that "No great genius has existed without a strain of madness," the 2009 study found that neuregulin 1 informed brain development and neural communication in ways that increased both one's creativity and one's likelihood of developing any number of psychoses, including schizophrenia and bipolar disorder.
While this result provided a scientific underpinning for the link between genius and madness, it's safe to say that most of us already understood, at least implicitly, that that link was there.
Surely, most of us had noticed the frequency with which our favorite writers and artists sank into depression, suffered breakdowns, and committed suicide relative to the general population.
Indeed, as researchers at Sweden's Karolinska Institute found in 2014, people working in creative fields (dance, writing, photography, and so on) were significantly more likely to have — or at least have a family history of — mental issues like schizophrenia, bipolar disorder, and autism.
The Karolinska researchers found that writers, in particular, were 121 percent more likely to suffer from bipolar disorder compared to the general population, and nearly 50 percent more likely to commit suicide.
However, it's not only clinically depressed writers like Ernest Hemingway and Virginia Woolf who demonstrate the link between genius and madness; it's also political leaders, inventors, and scientists who have battled mental disorders that both tormented and fueled them.
And sometimes, the link between genius and madness is even apparent in other historical figures whose world-changing albeit loathsome qualities force us to stretch our very notion of "genius." These are the tyrants and conquerors, like Napoleon and Stalin — people who changed history immeasurably regardless of where we think they fall on the spectrum from good to evil.