Influence of catechol-O-methyltransferase Val158Met on fear of pain and placebo analgesia

    loading  Checking for direct PDF access through Ovid


Higher levels of fear have been shown to partly explain individual differences in placebo analgesic responding. The catechol-O-methyltransferase (COMT) rs4680 Val158Met polymorphism has been associated with both increased placebo analgesia and increased fear-related behavior, in what appears to be inconsistent findings in the literature. The aim of the study was therefore to investigate placebo analgesia and fear-related processes with regard to the COMT genotype, to sort out whether the Met-allele is associated with increased placebo analgesia or increased fear of pain (FOP). A 3 Group (Emla, placebo and natural history) by 5 Test (2 pretest, 3 posttests) mixed design was used (N = 223). A contact heat-evoked stimulator was used to induce pain, and FOP was quantified with the Fear of Pain Questionnaire-III. Saliva was obtained for genotyping. As expected, we observed a significant interaction of test by group (P < 0.01), with lower pain report in the placebo group compared with the natural history group (P < 0.01). There was a main effect of the COMT genotype on fear of medical pain (P = 0.032), and Met-allele carriers reported significantly higher fear of medical pain compared with the Val-allele (P = 0.044). We observed no effect of the COMT genotype on mean pain-level report or placebo analgesia. Thus, we conclude that the Met-allele seems to be associated with the negative emotional process of fear, but not with placebo analgesia.

Related Topics

    loading  Loading Related Articles