Impulsiveness, serotonin genes and repetition of deliberate self-harm (DSH)

Background. Few studies have investigated independent associations of psych ological, biological and social variables with repeated deliberate self-har m (DSH). Serotonin function has been linked to impulsive and suicidal behav iour and genetic polymorphisms have been identified within the serotonin sy stem that could account for this link. This study tested hypotheses linking impulsiveness, genetic polymorphisms of tryptophan hydroxylase (TPH) and t he 5-HT2c receptor and repeated DSH. Methods. Individuals presenting after DSH were interviewed, completed perso nality questionnaires and gave venous blood samples. Genotypes were determi ned for TPH intron7 and 5-HT2c (cys-ser) polymorphisms. Follow-up to identi fy repetition of DSH was for 1 year. Results. Males with the 5-HT2c serine variant were more impulsive than thos e with the cysteine variant (0.39 standardized units, P = 0.041, 95 % CI 0. 017 to 0.076). There was no association between impulsiveness and the TPH i ntron7 polymorphism overall but a weak association with the L allele in men (0.41 standardized units, P = 0.05, 95 % CI 0.001 to 0.82). Impulsiveness, although high in the group as a whole, did not distinguish those who repea ted DSH. Conclusions. The personality trait of impulsiveness may in part be related to genotypes of the 5-HT2c receptor and TPH gene in men. Impulsiveness does not differ between those who do and do not repeat DSH.