Depression Affects Visual Perception

Article: De­pres­sion af­fects visual per­cep­tion
Source: University of Helsinki (Finland), via ScienceAlert
Published: March 29, 2021
Article: Visual Illusion Reveals That Depression Can Change How We Physically See The World
Source: ScienceAlert
Published: March 31, 2021

Differences in contrast perception of patterns between
people experiencing and not experiencing depression

Researchers in psychiatry and psychology from Finland investigated the effect of depression on visual perception through optical illusions. In particular, their study explored the difference in subjective brightness and contrast sensitivity (as well as inherent orientation sensitivity with regard to patterns) between 111 people who were experiencing major depressive episodes and 29 people who were not. Their results suggest that while the perception of brightness in the visual illusion was similar in both groups, people suffering from depression perceived the visual illusion in the patterns as weaker, and consequently the contrast as stronger compared to those not experiencing depression. “The contrast was suppressed by roughly 20% among non-depressed subjects, while the corresponding figure for depressed patients was roughly 5%,” one of the researchers explains. They further suggest that the difference in contrast perception in the scenario with patterns, which has an added layer of orientation perception, is due to altered cortical processing rather than altered retinal processing. This interpretation is supported by the data showing that there was little difference between the two groups in perception of the illusion without the patterns. And indeed perception of orientation relies on processing at higher levels than retinal cells. There are several limitations with a small self-reported observational study, which cannot untangle connections at the cellular level or at the level of cerebral visual processing. Nonetheless, the discovery that there are differences in visual perception during depression, which is consistent with studies about other altered mental states, could inform the development of vision testing to identify such disturbances in patients.

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Salmela V, Socada L, Söderholm J, et al. "Reduced visual contrast suppression during major depressive episodes." Journal of Psychiatry and Neuroscience.  46(2):222-231. (2021) http://doi.org/10.1503/jpn.200091