Published online Mar 19, 2021. doi: 10.5498/wjp.v11.i3.73
Peer-review started: December 1, 2020
First decision: December 12, 2020
Revised: December 23, 2020
Accepted: January 28, 2021
Article in press: January 28, 2021
Published online: March 19, 2021
Illness anxiety disorder (IAD) is a common, distressing, and debilitating condition with the key feature being a persistent conviction of the possibility of having one or more serious or progressive physical disorders. Because eye movements (EMs) are guided by visual-spatial attention, eye-tracking technology is a comparatively direct, continuous measure of attention direction and speed when stimuli are oriented. Researchers have tried to identify selective visual attention biases by tracking EMs within dot-probe paradigms because the dot-probe paradigm can distinguish these attentional biases more clearly.
There are numerous studies that have investigated individuals with high social anxiety, generalized anxiety disorder, and depressive disorder, using EMs and a modified probe detection task to pictures of faces. However, no studies have provided an in-depth analysis of illness anxiety disorder using EMs.
Using the dot-probe paradigm, our primary aim in the current study was to explore the specificity of attention bias in IAD. In addition, we aimed to examine whether patients will display orienting attention biases, reflected by fixating first and more rapidly on illness stimuli than other alternatives.
A case-control study design was used for the study, with the sample consisting of an IAD patient group and a healthy control (HC) group. Participants were recruited via e-mail and newspaper advertisement from Beijing An’Ding Hospital. The patient group fulfilled the criteria for IAD (DSM-5 and formerly named hypochondriasis in DSM-4) according to the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR). The stimuli used in the dot-probe task consisted of 128 pictures including 35 pictures from China internet sources, and 93 pictures selected from the International Affective Pictures System, which were grouped into four main categories: Illness-related, social threat, positive, and neutral pictures. These pictures were used to assess attentional bias in IAD patients. All four EM indicators were statistically analyzed using independent sample t-test. The differences between IAD group and HC group were compared on different types of images. The mean value of the group was compared with that of independent samples test, and P < 0.05 indicated that the difference was statistically significant.
When presented with disease-related images, the first-fixation direction of the IAD group was lower than that of the HC group (t = -2.467, P = 0.017); while presented with neutral images, it was higher than that of HC group (t = 2.467, P = 0.017). When the participants were presented with the disease–neutral image pairs, independent sample t-test found that the first-fixation duration of the IAD group (280.476 ± 55.154) for the disease picture was significantly greater than that of the HC group (252.807 ± 45.075) (t = 2.128, P = 0.038). When the participants were presented with the disease–social threat image pairs, independent sample t-test found that the first-fixation duration of the IAD group (281.20 ± 61.472) for the disease picture was significantly greater than that of the HC group (246.40 ± 30.991; t = 2.769, P = 0.008). There was also a difference in the social threat picture (IAD group: 296.86 ± 58.129, HC group: 266.37 ± 40.172; t = 2.363, P = 0.022). Independent sample t-test showed the overall fixation frequency bias toward the disease images in the IAD group was higher than in the HC group (t = 1.841, P = 0.071), and fixation frequency bias toward the positive images was lower than in the HC group (t = -1.841, P = 0.071).
Patients with IAD have an attention bias that is mainly manifested as an overall attentional avoidance when presented illness-related stimuli with disease, positive, and neutral stimuli, as well as avoidance of attention at the early attention stage when presented with neutral stimuli; however, IAD performance showed higher delayed disengagement bias to illness and disease-related stimulus than did the HCs. In addition, this study found that patients with suspected disorders with significant anxiety symptoms show attention bias in the late stage of attention processing, and struggle to dismiss the stimulus, showing delayed detachment.
This study suggests that patients with IAD have attention bias and this may have provided a new way of identifying IAD symptoms using the eye-tracking evaluation method.