AN INVESTIGATION OF THE PLACEBO-EFFECT AND AGE-RELATED FACTORS IN THEREPORT OF NEEDLE PAIN FROM VENIPUNCTURE IN CHILDREN

To examine the potential role for a placebo cream in reducing reported needle pain severity in children, and the impact of age-related facto rs on pain self-report, a convenience sample of 117 children scheduled for venipuncture were randomly assigned to one of three treatments: ( a) placebo cream with the suggestion that it might help reduce needle pain, (b) placebo cream with no indication as to the cream's purpose, and (c) no cream (control group). In allocation to treatment, children were stratified by age group, (3-7, 8-11, 12-17 years). They rated th eir needle pain severity (both predicted and reported) using the Faces Pain Scale, and rated their anxiety about the procedure using the Chi ldren's Anxiety and Pain Scale. Children in the cream groups were also asked whether they thought the cream had helped. Using video-tapes, a n independent observer, blind to the placebo manipulation, rated each child's reaction to the needle. For the two groups receiving cream, 83 % of those children told it might help stated that they believed it di d, as compared with only 33% of children who received the cream but we re told nothing of its purpose. These beliefs, however, were not refle cted in self-report ratings of pain which showed no statistically sign ificant treatment effect. Similarly, children who gave higher preproce dural anxiety ratings were no more likely to report less pain as a res ult of receiving the cream. There was, however, a treatment effect on the observer's ratings: children receiving cream plus suggestion were assigned significantly lower ratings of pain-related behaviour than th ose children who received the cream alone. While venipuncture was asso ciated with only mild levels of pain, younger children, irrespective o f treatment group, did report more pain than older children. Hierarchi cal regression analysis indicated that 60% of the variance in self-rep orted pain severity scores could be accounted for by how much the chil d thought the needle would hurt, how anxious the child was about recei ving the needle, gender (higher pain ratings associated with girls), a nd estimated body surface area (higher pain ratings associated with sm aller bodies). We conclude that the efficacy of placebo treatments for needle pain in children may depend on the suggestion of a possible be nefit rather than upon treatment application per se. (C) 1997 Internat ional Association for the Study of Pain. Published by Elsevier Science B.V.