Individuals battling major depressive episodes were found to have abnormal visual processing, according to a Finnish study suggesting the altered perception involves changes in the cerebral cortex.
Findings published in the Journal of Psychiatry and Neuroscience stemmed from data involving 111 patients and 29 healthy controls. The patients under study were battling unipolar disorder, bipolar disorder and borderline personality disorder who underwent major depressive episodes.
The team of researchers from the University of Helsinki conducted two visual tests, and participants reported back the brightness and contrast of simple visual patterns. The team followed up with 74 patients after seven months and ran repeat measurements.
“What came as a surprise was that depressed patients perceived the contrast of the images shown differently from non-depressed individuals,” said Viljami Salmela, Academy of Finland research fellow and corresponding study author, in a related release.
“Patients suffering from depression perceived the visual illusion presented in the patterns as weaker and, consequently, the contrast as somewhat stronger, than those who had not been diagnosed with depression,” reads the release.
“The contrast was suppressed by roughly 20% among non-depressed subjects, while the corresponding figure for depressed patients was roughly 5%,” Salmela said.
The team called for further research to explore altered visual processing resulting from depression to help develop therapies for mental disorders. Salmela also noted that assessing and advancing the visual perception tests would be beneficial for identifying patients’ altered processing.