Researchers at the University of Freiburg in Germany showed previously that people with depression have difficulty detecting black-and-white contrast differences.
Publishing a new report in Biological Psychiatry, these scientists combined neuropsychiatric and ophthalmologic investigations to focus on the response of the retina to varying black-and-white contrasts. Specifically, they measured the pattern electroretinogram, which is like an electrocardiogram (ECG) of the retina of the eye, in patients with depression and healthy individuals.
They found dramatically lower retinal contrast gain in the depressed patients, regardless of whether or not they were receiving antidepressant medication. There was also a significant correlation between contrast gain and severity of depression, meaning those with the most severe symptoms of depression also had the lowest retinal responses. The electrophysiological signal of response was sufficiently consistent to distinguish most depressed patients from the healthy subjects.
"These data highlight the profound ways that depression alters one's experience of the world," commented Dr. John Krystal, Editor of Biological Psychiatry. "The poet William Cowper said that 'variety's the very spice of life', yet when people are depressed, they are less able to perceive contrasts in the visual world. This loss would seem to make the world a less pleasurable place."
Lead author Dr. Ludger Tebartz van Elst noted that although these findings are strong, they still need to be replicated in further studies. However, "this method could turn out to be a valuable tool to objectively measure the subjective state of depression, having far-reaching implications for research as well as clinical diagnosis of and therapy for depression."
The article is "Seeing Gray When Feeling Blue? Depression Can Be Measured in the Eye of the Diseased" by Emanuel Bubl, Elena Kern, Dieter Ebert, Michael Bach, and Ludger Tebartz van Elst. The authors are affiliated with the Department of Psychiatry and Psychotherapy, Albert-Ludwigs-University of Freiburg, Freiburg, Germany. Bach is also with Universitats-Augenklinik Freiburg, Sektion Funktionelle Sehforschung, Freiburg, Germany. The article appears in Biological Psychiatry, Volume 68, Issue 2 (July 15, 2010), published by Elsevier.
John H. Krystal, M.D. is Chairman of the Department of Psychiatry at the Yale University School of Medicine and a research psychiatrist at the VA Connecticut Healthcare System. His disclosures of financial and conflicts of interests are available at journals.elsevierhealth.com/webfiles/images/journals/bps/Biological_Psychiatry_Editorial_Disclosures_08_01_09.pdf.
About Biological Psychiatry
This international rapid-publication journal is the official journal of the Society of Biological Psychiatry. It covers a broad range of topics in psychiatric neuroscience and therapeutics. Both basic and clinical contributions are encouraged from all disciplines and research areas relevant to the pathophysiology and treatment of major neuropsychiatric disorders. Full-length and Brief Reports of novel results, Commentaries, Case Studies of unusual significance, and Correspondence and Comments judged to be of high impact to the field are published, particularly those addressing genetic and environmental risk factors, neural circuitry and neuro-chemistry, and important new therapeutic approaches. Concise Reviews and Editorials that focus on topics of current research and interest are also published rapidly.
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