Depressed individuals do not display an information-processing bias towards negative emotional stimuli, according to new research published in the European Journal of Neuroscience. Instead, they appear to have blunted attention to both positive and negative emotional stimuli compared to neutral stimuli.
“Depression is a complex illness that affects multiple aspects of an individual’s life. Depression is characterised by a ‘negative triad’: a negative view of the self (low self-esteem), a negative view of the world and a negative view of the future (hopelessness),” said study author Sanjay Kumar, a senior lecturer in cognitive neuroscience at Oxford Brookes University.
“Neuroscientific research in depression has primarily focused on understanding the emotional experience of depressed individuals. However, there isn’t much research into understanding the neuroscientific basis of having a negatively skewed view about oneself in depression.”
“My research is trying to understand how ‘the self’ operates in depressed individuals and how such an understanding can be integrated in therapeutic interventions. My interest is also to understand how the self regulates experience and expression of different kinds of emotion in individuals with depression.”
To examine the relationship between self-referential information processing and depression, Kumar and his colleagues had 20 depressed and 20 non-depressed participants complete a computerized perceptual matching task.
During a learning phase of the task, participants were repeatedly shown geometric shapes that were paired with either the word “self” or “other.” The participants were asked to remember which shape was paired with which word.
The participants were then shown various combinations of the geometric shapes and the words, and indicated whether the pairings were correct or incorrect as quickly and as accurately as possible. During this phase, each shape was also filled with a drawing of a happy, sad or neutral face.
The researchers observed increased accuracy and perceptual processing speed for “self” pairings compared to “other” pairings regardless of facial emotion in both the depressed group and the control group. Compared to the control group, however, the depressed group exhibited reduced accuracy and perceptual processing speed for geometric shapes that contained a happy or sad face.
“Interestingly, depression specific biases towards neutral faces over happy and sad faces were observed at short (150ms) stimulus presentations,” the researchers noted.
“There is a prevalent notion that depressed individuals have a bias towards experiencing negative emotion. We, on the contrary, show that individuals with depression do not show any specific bias to negative or positive emotion. The overall range of their emotional experience/expression is limited. In simplistic terms, we can say that they have emotional numbness and reduced reactivity to both positive and negative conditions,” Kumar told PsyPost.
But the study — like all research — includes some caveats.
“This is a preliminary study with relatively small sample size. We would like to explore this finding further in a larger study. There were some participants who had comorbid anxiety, which raises the question if reduced emotional experience is affected by presence of anxiety,” Kumar explained.
“There are other aspects of depression that need to be investigated as well, such as how the self is integrated with emotional systems at the brain level to produce a self-referential emotional experience (emotional experience from own or someone else’s perspective). We are planning to investigate if the self is able to integrate emotional experiences in individuals who are experiencing depression as effectively as it does in healthy individuals.”
The findings, along with future research, could help develop new treatments for depression.
“This is an exciting stage of research in this field, which is likely to influence the kind of diagnostic questions we ask patients with depression. We may utilize these findings in developing new therapeutic approaches based on self-referential processing. In fact, we have started a research work utilizing principles of ‘attention bias modification’ where we train individuals with depression with their own happy faces to bring about the desired changes in their symptoms,” Kumar said.
The study, “Self‐referential processing and emotion context insensitivity in major depressive disorder“, was authored by Lucy McIvor, Jie Sui, Tina Malhotra, David Drury, and Sanjay Kumar.
(Image by Talip Özer from Pixabay)