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 inv estigated whether the serotonin transporter (5-HTT) gene encoding the prote in responsible for the reuptake of serotonin from the synapse after its rel ease from serotonergic neurons is a susceptibility factor for suicidal beha vior Methods: A functional polymorphism of the 5-HTT gene (a 44-base pair insert ion/deletion in the 5-HTT-linked polymorphic region [5-HTTLPR]) was studied in a population of 237 consecutive patients with affective disorder (unipo lar or bipolar) and 187 control subjects. Ninety-nine patients had attempte d suicide at feast once, of whom 26 made a violent attempt. Results: No association was found between the "s" allele of the 5-HTTLPR an d suicide attempt; however, there was a significant difference in allele di stributions between patients who had made violent suicide attempts and cont rol subjects. Conclusions: A generic 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 replicat e these findings. (C) 2000 Society of Biological Psychiatry.