The TPH intron 7 A218C polymorphism and TCI dimension scores in alcohol-dependent patients: hints to nonspecific psychopathology

Abstract

Aims A linkage of certain alleles of the tryptophan hydroxylase (TPH) intron 7 A218C polymorphism to suicidality and antisocial behaviour has been described. The aim of our study was to find any association between dimensions of the Temperament and Character Inventory (TCI) indicating impulsivity and the TPH polymorphism alleles in unselected alcohol-dependent patients and age-matched controls. Methods We examined 159 alcohol-dependent patients and 161 controls with the TCI and genotyped them for the TPH intron 7 A218C polymorphism alleles. Results Although homozygous TPH genotypes were found more often in alcohol-dependent patients than in controls, an association between TCI dimensions and TPH alleles was not observed in the complete sample. Alcohol-dependent patients, however, scored significantly higher for harm avoidance (HA) and lower for self-directedness (SD) than controls regardless of TPH genotype. Among controls, for those with the A/A genotype, harm avoidance was as high as in the group of alcohol-dependent patients, persistence (P) in that genotype was significantly lower than for all other genotypes in the patient and control group. Conclusion Even if there is no association between TCI dimensions and TPH genotype in our sample, hints to nonspecific psychopathology in connection with the A/A genotype are found.