Scientists observe an abnormal attentional bias in depressed individuals

An eye-tracking study in China found that individuals with depression looked at threatening and neutral images longer than healthy individuals in an experimental setting. They also tended to spend more time viewing these images compared to positive ones. The longer viewing times suggest that they were paying more attention to threatening and neutral content. The research was published in the Journal of Affective Disorders.

Depression, or major depressive disorder, is a mood disorder characterized by persistent feelings of sadness, emptiness, or irritability, often accompanied by a loss of interest in previously enjoyable activities. It affects people of all ages and backgrounds and is one of the leading causes of disability worldwide.

Symptoms may also include fatigue, changes in appetite or weight, sleep disturbances, feelings of worthlessness or guilt, and difficulty concentrating or making decisions. In more severe cases, depression can lead to thoughts of death or suicide. It may be triggered by stressful life events, trauma, medical conditions, or occur without an obvious cause.

Depression also appears to influence how people process information. Individuals with depression tend to focus more on negative or sad content while paying less attention to neutral or positive information. This phenomenon, known as attentional bias, can reinforce negative thought patterns and contribute to the persistence and severity of depressive symptoms.

Study author Xiaobo Liu and his colleagues aimed to investigate whether individuals with depression display an attentional bias toward threatening images. They hypothesized that depressed participants would pay more attention to threatening pictures compared to healthy individuals. To test this, they conducted an eye-tracking experiment.

Free daily newsletter

The study involved 100 individuals diagnosed with major depressive disorder and 100 healthy control participants. The healthy participants were matched to the depressed group by age, education, and gender. The average age in both groups was between 27 and 28 years. Women made up 76% of the depressed group and 73% of the control group. On average, the depressed participants had been experiencing symptoms for about one year, though there was considerable individual variation.

All participants completed assessments for depression and anxiety using the 24-item Hamilton Depression Rating Scale and the Hamilton Anxiety Rating Scale. They also participated in an eye-tracking task that involved viewing a series of images from the International Affective Picture System, categorized as threatening, positive, or neutral. Participants were instructed to view the images as if they were watching television, while an eye-tracking device recorded their gaze patterns.

Threatening images typically depicted scenes of danger, violence, or injury—such as aggressive animals, weapons, or accidents—and were intended to provoke fear or anxiety. Positive images included content like smiling faces, nature scenes, or playful animals. Neutral images showed everyday objects or people with neutral expressions and were designed to evoke little emotional response.

The results revealed that individuals with depression spent significantly more time looking at threatening and neutral images compared to healthy participants. They also made fewer saccades—rapid eye movements between fixations—suggesting less visual exploration of these images. Additionally, compared to how they viewed positive images, depressed participants spent more time fixating on threatening and neutral images and showed reduced eye movement. These findings indicate an increased attentional focus on emotionally negative or ambiguous content. Healthy participants did not show similar patterns.

“Patients with MDD [major depressive disorder] exhibit abnormal attentional bias toward threatening stimuli, which is associated with the severity of retardation symptoms in MDD,” the authors concluded.

The study offers insights into how individuals with depression process emotionally charged visual information. However, the researchers caution that eye movements are not a perfect measure of attention. While eye-tracking devices can record where someone is looking and how long they maintain their gaze, it does not definitively confirm whether they are mentally engaged with that content.

The paper, “Attentional bias toward threatening stimuli in major depressive disorder: A free-viewing eye-tracking study,” was authored by Xiaobo Liu, Yuxi Li, Yuan Chen, Chen Xue, Jin Fan, Jiaming Zhang, Dongling Zhong, Qinjian Dong, Zhong Zheng, Juan Li, and Rongjiang Jin.