The effects of catastrophic thinking about pain on attentional interference by pain: no mediation of negative affectivity in healthy volunteers and in patients with low back pain.

BACKGROUND: Previous studies have shown that catastrophic thinking about pain enhances attentional interference in healthy volunteers. OBJECTIVE: To investigate whether the attentional effects of pain catastrophizing can be accounted for by the more general predisposition of negative affectivity. METHODS: Sixty-seven pain-free students participated in the first experiment, and 33 patients with chronic low back pain participated in the second experiment. In both experiments, participants performed an auditory reaction time task while being exposed to a series of threatening electrocutaneous stimuli. Retardation in reaction times to auditory probes during pain was taken as an index of the attentional interruption by pain. Participants also completed self-report instruments of negative affectivity and pain catastrophizing. RESULTS: In both experiments, pain catastrophizing enhanced attentional interference by pain. This effect was most pronounced immediately after the onset of the electrocutaneous stimulus. The effect remained after controlling for the effects of negative affectivity. CONCLUSIONS: Catastrophic thinking about pain enhances attentional interruption by pain in normal samples, as well as in clinical samples of patients with chronic back pain. This effect is specific to pain catastrophizing and cannot be explained by the more general disposition of negative affectivity.