Serotonin transporter polymorphism and harm avoidance personality in chronic tension-type headache.

To investigate the 5-HTT-gene-linked polymorphic region (5-HTTLPR) genotypes and harm avoidance (HA) dimension in chronic tension-type headache (CTH). Serotonin transporter protein (5-HTT) is a key modulating protein in synaptic serotonergic neurotransmission. Among serotonin gene-linked polymorphism, promoter located in the regulatory region of the 5-HTTLPR has two alleles (short and long) with different transcriptional efficiencies. The HA personality trait may be heritable and associated with serotonergic neurotransmitter activity. We amplified the 5-HTTLPR by means of polymerase chain reaction and performed genotype polymorphism analyses and we investigated the serotonin-related personality trait by evaluating the HA dimension in tridimensional personality questionnaire (TPQ) in 107 patients with CTH and in 100 healthy controls. We found an excess frequency of the short allele and a different genotype distribution in patients with CTH. S/S genotype frequency was significantly higher in patients with CTH (76%) than in those with controls (59%; P=.02). Patients with CTH had significantly higher HA scores (21.4+/6.3) than controls (16.3+/-6.1). This suggests a serotonergic activity might be involved in the development of CTH and 5-HTTLPR might be one of the genetically contributing factors.