Pain-related bias in the classification of emotionally ambiguous facial expressions in mothers of children with chronic abdominal pain.

This study sought to determine whether mothers of young people with chronic abdominal pain (CAP) compared to mothers of pain-free children show a pain recognition bias when they classify facial emotional expressions. One hundred demographically matched mothers of children with CAP (n=50) and control mothers (n=50) were asked to identify different emotions expressed by adults in 2 experiments. In experiment 1, participants were required to identify the emotion in a series of facial images that depicted 100% intensity of the following emotions: Pain, Sadness, Anger, Fear, Happiness, and Neutral. In experiment 2, mothers were required to identify the predominant emotion in a series of computer-interpolated ("morphed") facial images. In this experiment, pain was combined with Sad, Angry, Fearful, Happy, and Neutral facial expressions in different proportions-that is, 90%:10%, 70%:30%, 50%:50%, 30%:70%, 10%:90%. All participants completed measures of state and trait anxiety, depression, and anxiety sensitivity. In experiment 1, there was no difference in the performance of the 2 groups of mothers. In experiment 2, it was found that overall mothers of children with CAP were classifying ambiguous emotional expressions predominantly as pain. Mean response times for CAP and control groups did not differ significantly. Mothers of children with CAP did not report more anxiety, depression, and anxiety sensitivity compared to control mothers. It is concluded that mothers of children with CAP show a pain bias when interpreting ambiguous emotional expressions, which possibly contributes to the maintenance of this condition in children via specific parenting behaviours.