Color and Depression in the Eye of the Beholder

As humans we’ve always had the tendency to associate specific colors with emotions. Art historians talk about “the blue period,” a series of paintings by Picasso in which he expressed his trauma following the suicide of a friend through a series of dark paintings with a strong level of contrast. On a more everyday level, the phrase “feeling blue” is a good example of how we link color to feeling.

A few studies have suggested that there might be some empirical truth to these metaphors. For example, the drug Reserpine is known to induce depression in humans and is also known to cause extreme photosensitivity in mice. Similarly, people with bipolar disorder are known to have a hypersensitivity to light. What isn’t clear, however, is whether this sensitivity is caused by the eye itself or by the various parts of the brain which process images. And of course the possibility remains that this whole apparent link between visual stimuli and mood could be a side effect of antidepressant drugs.

Recently, a research group at the University Hospital of Freiburg in Germany has addressed these concerns. Here is how they studied it. Groups of patients with depression and healthy volunteers were presented with a grey-colored chess-board. A technique called pattern electroretinography was used to measure the electrical response at the cornea. This technique gave an indication of the activity of the ganglion cells in the retina, which are believed to play a role in processing visual information and sending it along the optic nerve to the brain. In short, it’s a direct way to measure how well the retina perceives and amplifies the contrast in images.

The results couldn’t have been clearer. Patients with depression showed much less perception of contrast than the control group. What’s more, this was independent of any medication — patients who were on antidepressants showed the same response as those who weren’t medicated. In fact, the study was able to predict depression with an accuracy of approximately 90%.

The authors stress that further research is needed (don’t they always?), but if their conclusions are correct and are replicated in future work, they would have profound impact on the fields of psychiatry and physiology. On a more sentimental level, if we look at the example of Picasso, it gives us a small hint of how a natural phenomenon like depression might influence a cultural phenomenon like impressionistic art as well as open a window into the mind of a genius.

--Anders Aufderhorst-Roberts

Reference:

Bubl, E., Kern, E., Ebert, D., Bach, M., & van Elst, L. Seeing Gray When Feeling Blue? Depression Can Be Measured in the Eye of the Diseased. Biological Psychiatry 68, 205–208 (2010).