The popular perception of creative thinkers and artists is that they often also have mental disorders—the likes of Vincent van Gogh or Sylvia Plath suggest that creativity and madness go hand in hand. Past research has tentatively confirmed a correlation; scientific surveys have found that highly creative people are more likely to have mental illness in their family, indicating a genetic link. Now a study from Sweden is the first to suggest a biological mechanism: highly creative healthy people and people with schizophrenia have certain brain chemistry features in common.

A research team at the Karolinska Institute in Stockholm studied 13 mentally healthy, highly creative men and women. As noted in the paper published in May in PLoS ONE, other scientists had previously found that divergent thinking, or the ability to “think outside the box,” involves the brain’s dopamine communication system. The Swedish research team used PET scanning to determine the abundance of a particular dopamine receptor, or sensor, in the creative individuals’ thalamus and striatum, areas that process and sort information before it reaches conscious thought—and that are known to be involved in schizophrenia. The team found that people who had lower levels of dopamine receptor activity in the thalamus also had higher scores on tests of divergent thinking—for instance, finding many solutions to a problem.

Previous work has shown that people with schizophrenia also have lower dopamine receptor activity in the thalamus—and the scientists suggest in their paper that this striking similarity demonstrates a “crucial” link between creativity and psychopathology. “Thinking outside the box might be facilitated by having a somewhat less intact box,” writes lead author Fredrik Ulln, a cognitive scientist at Karolinska.