Attentional bias to pain-related information: a meta-analysis.

This meta-analysis investigated whether attentional bias, that is, the preferential allocation of attention to information that is related to pain, is a ubiquitous phenomenon. We also investigated whether attentional bias effects are related to the methodological quality of the study, to procedural differences in their measurement, or to individual differences in pain severity, pain-related fear, anxiety, and depression. Results indicated that individuals who experience chronic pain (n=1023) display an attentional bias towards pain-related words or pictures, but this bias was of a small effect size (d=0.134), and did not differ from that in control groups (d=0.082; n=1398). No evidence was found for an attentional bias towards pain-related words and pictures for acute pain (d=0.049), procedural pain (d=0.142), and experimental pain (d=0.069). However, research in which attentional bias towards signals of impending experimental pain in healthy volunteers was investigated, revealed an attentional bias of medium effect size (d=0.676). Moderator analyses in the chronic pain group identified important procedural variables that affected the presence and magnitude of an attentional bias towards pain-related words and pictures, that is, type and exposure time of pain-related information. None of the individual difference variables affected the magnitude of the attentional bias. Implications of current findings and future directions are discussed.