Possible association between serotonin transporter gene polymorphism and violent suicidal behavior in mood disorders.

BACKGROUND

Genes involved in the serotonin system are major candidates in association studies of suicidal behavior. In this case-control study we investigated whether the serotonin transporter (5-HTT) gene encoding the protein responsible for the reuptake of serotonin from the synapse after its release from serotonergic neurons is a susceptibility factor for suicidal behavior.

METHODS

A functional polymorphism of the 5-HTT gene (a 44-base pair insertion/deletion in the 5-HTT-linked polymorphic region [5-HTTLPR]) was studied in a population of 237 consecutive patients with affective disorder (unipolar or bipolar) and 187 control subjects. Ninety-nine patients had attempted suicide at least once, of whom 26 made a violent attempt.

RESULTS

No association was found between the "s" allele of the 5-HTTLPR and suicide attempt; however, there was a significant difference in allele distributions between patients who had made violent suicide attempts and control subjects.

CONCLUSIONS

A genetic variant of the 5-HTT gene may predispose individuals to violent suicidal behavior. The precise phenotype associated with the 5-HTT gene is unclear, and therefore further studies are required to replicate these findings.