B. Goodenough et al., AN INVESTIGATION OF THE PLACEBO-EFFECT AND AGE-RELATED FACTORS IN THEREPORT OF NEEDLE PAIN FROM VENIPUNCTURE IN CHILDREN, Pain, 72(3), 1997, pp. 383-391
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.