5-HTTLPR and COMT Val158Met are not associated with alexithymia: New evidence and meta-analyses.

BACKGROUNDS: Alexithymia refers to the difficulties in identifying and describing one's own emotions, lacking of imagination, and an externally oriented thinking style. Studies up to date have examined the associations of the 5-HTTLPR and COMT Val158Met polymorphisms with alexithymia. However, the previous findings were mixed.

METHODS: We replicated the associations by scoring on alexithymia with the 20-item Toronto Alexithymia Scale and genotyping the polymorphisms of 5-HTTLPR and COMT Val158Met in a large population of college students (N = 1698). Moreover, we also meta-analyzed the associations with five samples (N = 7517) for the 5-HTTLPR and with five samples (N = 2186) for the COMT Val158Met.

RESULTS: Neither the replicated study nor the meta-analyses indicated the 5-HTTLPR and COMT Val158Met were associated with alexithymia.

CONCLUSIONS: The findings suggest that the 5-HTTLPR and COMT Val158Met polymorphisms are not associated with alexithymia. However, the genetic-environmental studies with different ethnicity and psychopathology should be carried in future.