Depression affects visual perception

Information processing by the brain is altered in depressed individuals, according to the findings of a study conducted at the University of Helsinki.

The study found that in depressed patients, the processing of visual perceptions is also different, said the university in a press release on Monday.

Researchers specialised in psychiatry and psychology at the University of Helsinki investigated the effects of depression on visual perception.

The study findings confirmed that the processing of visual information is altered in depressed people, a phenomenon most likely linked to the processing of information in the cerebral cortex.

The study report was published in the Journal of Psychiatry and Neuroscience.

The study compared the processing of visual information by patients with depression with that of a control group by utilising two visual tests. In the perception tests, the study subjects compared the brightness and contrast of simple patterns.

“What came as a surprise was that depressed patients perceived the contrast of the images shown differently from non-depressed individuals,” said Academy of Finland Research Fellow Viljami Salmela.

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.

“The contrast was suppressed by roughly 20% among non-depressed subjects, while the corresponding figure for depressed patients was roughly 5%,” added Salmela.

Identifying the changes in brain function, underlying mental disorders is important in order to increase understanding of the onset of these disorders and of how to develop effective therapies for them.