The idea that sadness somehow kindles creativity is a popular and long-lasting one. Its roots go back to antiquity; even Aristotle noted that those who excelled in the arts, politics and philosophy had a tendency toward "melancholia". The artistic canon appears to be full of people whose dark mental states kindled their brilliance but also brought their lives to an early end - such as van Gogh, Rothko, Hemingway and Woolf.
This notion is widespread, but in science it remains controversial. Research has not really demonstrated a direct link between sadness and many of the most lasting achievements in art history.
Now, a fascinating new study from an economist at the University of Southern Denmark appears to show that link.
Karol Jan Borowiecki examined the emotional state of three of the West's most influential composers through the full course of their lives. Using linguistic analysis software that scanned the text for positive and negative emotions, such as joy, love, grief and hurt, he analysed 1400 letters written by Mozart, Beethoven and Liszt to their friends, colleagues and loved ones.
He then compared that data with the compositions they produced in a given time period, looking in particular at their most influential and transformative works.
What he found appears to bear out popular ideas about creativity and melancholy: a link between periods of negative emotions, especially sadness, and artistic brilliance.
The three composers lived in roughly the same time period and region of Europe, and all had turbulent lives, sometimes tragic and sometimes jubilant.
Mozart was lauded as a child prodigy but was driven to depression when he was forbidden from marrying a girl he loved and his mother suddenly died. After the death of his father, Liszt became his family's sole breadwinner at a young age; he was never able to marry the woman he loved, and he saw his children pass away before him. Beethoven discovered at 30 that he was going deaf, and he was emotionally stricken when at the end of his life a nephew under his care tried to commit suicide.
Borowiecki's analysis suggests that the causes of these composers' happiness and sadness were the same as any ordinary individual. Negative emotions appeared when they fell on hard times financially, when their health became poor or especially when a close relative died.
Borowiecki's analysis suggests that negative emotions are not just correlated with creativity but that they actually have a causal effect on it.
"Creativity, measured by the number of important compositions, is causally attributable to negative moods, in particular to sadness," he writes.
Composers appeared to write more letters in times of negative emotion - especially when they were angry - and fewer when they were happy.