A New York Times story grabbed my attention today, “Just Manic Enough: Seeking Perfect Entrepreneurs”. Telling the story of 21-year-old Seth Priebatsch – a guy who successfully secured a $750,000 investment from venture capitalists for what some may argue is just a crazy idea – the article showed how this certain young entrepreneur seemed to tread a very fine line between being a workaholic, self-confident entrepreneur, and full-blown clinical manic. With hypomania, people experience similar mood and behavior swings as those with clinical mania. But although the two conditions share common symptoms like increased vigor, persistently elevated moods, and reduced desire or need for sleep, hypomania does not seem to prevent people from experiencing a fully functioning life. In fact, some have argued the symptoms may be conducive to success. The NYT article highlighted several well-known, professionally-accomplished hypomaniacs, such as George S. Patton and Theodore Roosevelt, both of whom seemed able to keep the condition in check – arguably, just enough – to rise to the top of their respective professional circles.
Over the past few weeks, I’ve grown increasingly interested in the connection between creativity and mental illness. There have been numerous books and articles written on the ideas that famous writers and artists, many of whom ended up taking their own lives, suffered from bipolar disorder or other clinical mood problems.
So I started looking into the scientific literature around this idea, to see if researchers have been able to pinpoint specific brain circuits that prove the existence of this alleged gray-zone between creativity and mental illness. In other words: could the same brain structures fuel a raging fire of creativity in an individual on moment, yet cause disastrous mental illness at a later point in time?
[NOTE: In a very cursory search, I found an enormous amount of information. I plan to share the most interesting findings I come across over the next few weeks as short blog posts.]
A study published in May 2010 in the journal, PLoS ONE, by Örjan de Manzano and colleagues from the Stockholm Brain Institute at Karolinska Institutet, Stockholm, Sweden tapped into the creative mind of healthy individuals using both positron-emission tomography (PET) brain imaging and standard psychological tests.
The Berliner Intelligenz Struktur Test is a divergent thinking exercised often used to gauge creative prowess. The researchers would ask the participants to list every possible use for a brick that comes to mind within a given amount of time, or create as many novel drawings they can using just a few line segments. The ability to rattle off variations of an initial idea taps into the associative mind, and is not necessarily correlated to general knowledge or intelligence, at least in the standard definitions of the terms.
Örjan de Manzano and colleagues hypothesized that creativity may in fact be linked to defunct dopamine signaling in certain areas of the brain. After all, from previous studies, they already knew that people carrying the A1 allele of the dopamine-receptor gene DRD2 TAQ IA exhibited increased creativity, as seen by higher scores on the divergent thinking test, with absolutely no changes in generalized intelligence.
Using PET imaging, researchers can determine the functionality of D2 receptors by introducing a radiotracer that binds to these receptors. By measuring the D2 receptor binding potential of these tracers – a measure of how long the radiotracer stays attached to the receptor substrate – researchers can measure the strength of dopamine signaling in different areas of the brain.
In a very small group of healthy volunteers (this is probably the biggest criticism of the study), Örjan de Manzano and colleagues found that the level of D2 receptor binding potentials in the thalamus were negatively correlated (r = -0.64) to their score in the divergent thinking test, which means the more creative the people were (as determined by the divergent thinking test), the LESS dopamine activity they had in the thalamus. No such correlations were found in other areas of the brain, such as the striatum or the frontal cortex.
The thalamus is often considered a gate to the cortex, the area where much of the higher order processing of stimuli takes place. The cortex is the region where we essentially discriminate one sound from another, or determine a circle is different than a square. The authors think that less dopamine signaling in the thalamus leads to a less regulated flow of information to the cortex. In other words, the creative brain isn't filtering out information at very low levels – it’s actually letting more and more through. Increased chatter in the cortex may transiently put the brain in a different state, allowing the mind to rapidly switch between thoughts and ideas.
As the authors point out, the sudden burst of info would more than likely come at a cost to the cortex, however, and may materialize as a decrease in selective attention. A study has corroborated this theory, showing that people who score higher in divergent thinking tasks may be more creative, but are also more easily distracted.
Although preliminary, this study suggests a powerful link between creativity and reduced dopamine signaling in the thalamus. If true, creativity might be due to more information making it past the thalamic gatekeeper, and into the cortex, where different neural circuits – ones that may not usually talk to each other – begin to harmonize in creative synchrony.
This paper offers no direct evidence that a less active thalamic filter correlates to mental illness. Still, the authors speculate how a more information moving through the thalamus might also be related to so-called positive symptoms in psychiatric disease. Though most of the discussion on mental illness relies on hand-waving explanations, the authors still clearly articulate a few good points. Hallucinations and delusions are thought to be due to an overactive cortex in one way or another, so the possible link is at the very least worth considering – perhaps in my next post.
photo via Flickr /yago1.com
de Manzano, ?., Cervenka, S., Karabanov, A., Farde, L., & Ullén, F. (2010). Thinking Outside a Less Intact Box: Thalamic Dopamine D2 Receptor Densities Are Negatively Related to Psychometric Creativity in Healthy Individuals PLoS ONE, 5 (5) DOI: 10.1371/journal.pone.0010670