A recent study in Nature Neuroscience suggests that genetic risks for schizophrenia and bipolar disorder are associated with artistic activity. These findings appear to present data to support the long-held societal belief that creativity and mental illness are linked, but the strength of the association is extremely small.

Previously, studies that attempted to link psychiatric disorders and creativity have either assessed the presence of psychiatric illness among eminent creative professionals or assessed the levels of creativity among psychiatric patients and their relatives. The approach used in the new study is unique in that it uses a large dataset to probe whether individual genetic variants are associated with both psychiatric illness and creativity.

To complete this study, the researchers examined a dataset of more than eighty-five thousand Icelanders (insert your Björk jokes here), recruited by a research clinic. Participants were genotyped, and their genetic risk of schizophrenia and bipolar disorder were assessed using the most recent genome-wide association study technique: polygenetic risk scores. In short, this technique looks at all the areas of the genome that have been associated with a greater risk of a disease and computes a single value for each individual's genotype.

The scores for schizophrenia and bipolar disorder were associated with the diseases, but didn't explain a lot of their incidence. The maximum variance that the scores explained were 5.5% for schizophrenia and 1.2% for bipolar disorder.

They then used these same scores and determined whether they were also associated with a creative career. Creative professionals were defined as anyone who’s ever had a job in dance, film, theater, visual arts, or writing. Statistically, they found that genetic risk of schizophrenia and bipolar disorder explained 0.24 percent and 0.26 percent of the variation in creativity, respectively.

As a control, they also probed several non-psychiatric diseases, including three that affect cognition, and found no significant association with those diseases and creativity.

To determine whether an association with creativity might be driven by educational accomplishment, they looked at the relationship between education and genetic risk of schizophrenia/bipolar disorder, finding that both risks were associated with increased educational attainment.

To test the replicability of their findings, the researchers looked at the relationship between genetic risk of schizophrenia/bipolar disorder and creativity among four longitudinal datasets from the Netherlands and Sweden, with approximately twenty-six thousand participants. For these analyses, they found that individuals with genetic risk of bipolar disorder or schizophrenia were 1.23 times more likely to be creative as measured by the same criteria, a statistically significant finding.

The authors conclude with the statement that creativity is “conferred, at least in part, by common genetic variants, [but] comes with an increased risk of psychiatric disorders conferred by the same genetic variants.” At present, the data doesn’t present a strong argument for a causal relationship, nor any evidence about the specific genes that may be linked to creativity. But, perhaps the most striking aspect is the relative weakness of the effects. The common variants used in these studies don't do a lot to increase the risk of these two psychiatric disorders, and their effect on creativity is also weak.

Because of these caveats, it’s imperative not to over-generalize these findings or over emphasize their importance to understanding the genetic underpinnings of creativity. Further large-scale data analysis probing this relationship will be needed to sort things out and provide a clearer picture of the strength of the underlying genetics.

Nature Neuroscience, 2015. DOI: 10.1038/nn.4040 (About DOIs).