Abstract

Background
Approximately one half of all patients with chronic daily headache report an associated regular use of analgesics, making the issue of an important public health matter. But the analysis of factors related to the development to analgesics overuse in chronic tension-type headache remain poorly unders- tood. We tried to establish the role played by chronic analgesics exposure in the natural course and clinical phenotype of headache in patients of chronic tension-type headache. And we also evaluated genetically determined innate factor that could exert a profound influence in development of analgesics overuse using serotonin transporter protein polymorphism and serotonergically related harm avoidance(HA) personality dimension. Methods: We surveyed headache characteristics via a standardized questionnaire in 38 patients with chronic tension-type headache with analgesics overuse(CTTH-AO) and in 40 patients with chronic tension- type headache with analgesics non-overuse(CTTH-NO), and in 100 healthy controls. We amplified sero- tonin transporter protein gene linked polymorphic region(5-HTTLPR) by means of polymerase chain reaction and performed genotype polymorphism analyses and investigated the serotonin related personality trait by evaluating the HA dimension in tridimensional personality questionare(TPQ). Results: We found significantly higher pain intensity and disability score in patients with CTTH-AO. Most of patients with CTTH-AO used caffeine contained compound analgesics as for instant pain relief drugs. There was excess frequency of the short allele and a different genotype distribution in patients with CTTH-AO. S/S genotype frequency was higher in patients with CTTH-AO(83%) than in those with CTTH-NO(74%) and controls(59%; P = 0.02). TPQ questionnaires showed significantly higher HA scores in both CTTH-AO(22.35.4) and CTTH-NO(19.96.7) compared with controls(16.36.1). In those of chronic tension-type headache, individuals with S/S allele have significantly higher frequency of analgesics usage (13.3/month) than with S/L, L/L allele(7.0/month). Conclusions: This suggests a serotonergic activity might be involved in development of analgesics over- use in chronic tension-type headache, and 5-HTTLPR might be one of the genetically contributing factors. Korean Journal of Headache 5(1):104-104, 2004