TY - JOUR T1 - Reduced visual contrast suppression during major depressive episodes JF - Journal of Psychiatry and Neuroscience JO - JPN SP - E222 LP - E231 DO - 10.1503/jpn.200091 VL - 46 IS - 2 AU - Viljami Salmela AU - Lumikukka Socada AU - John Söderholm AU - Roope Heikkilä AU - Jari Lahti AU - Jesper Ekelund AU - Erkki Isometsä Y1 - 2021/03/01 UR - http://jpn.ca/content/46/2/E222.abstract N2 - Background Previous studies have suggested that processing of visual contrast information could be altered in major depressive disorder. To clarify the changes at different levels of the visual hierarchy, we behaviourally measured contrast perception in 2 centre-surround conditions, assessing retinal and cortical processing.Methods As part of a prospective cohort study, our sample consisted of controls (n = 29; 21 female) and patients with unipolar depression, bipolar disorder and borderline personality disorder who had baseline major depressive episodes (n = 111; 74 female). In a brightness induction test that assessed retinal processing, participants compared the perceived luminance of uniform patches (presented on a computer screen) as the luminance of the backgrounds was varied. In a contrast suppression test that assessed cortical processing, participants compared the perceived contrast of gratings, which were presented with collinearly or orthogonally oriented backgrounds.Results Brightness induction was similar for patients with major depressive episodes and controls (p = 0.60, d = 0.115, Bayes factor = 3.9), but contrast suppression was significantly lower for patients than for controls (p < 0.006, d = 0.663, Bayes factor = 35.2). We observed no statistically significant associations between contrast suppression and age, sex, or medication or diagnostic subgroup. At follow-up (n = 74), we observed some normalization of contrast perception.Limitations We assessed contrast perception using behavioural tests instead of electrophysiology.Conclusion The reduced contrast suppression we observed may have been caused by decreased retinal feedforward or cortical feedback signals. Because we observed intact brightness induction, our results suggest normal retinal but altered cortical processing of visual contrast during a major depressive episode. This alteration is likely to be present in multiple types of depression and to partially normalize upon remission. ER -