No association between non-violent suicidal behavior and the serotonin transporter promoter polymorphism

There is compelling evidence that suicidal behavior is associated with the dysfunction of the serotonin system. A functional polymorphism in the promoter region of the serotonin transporter gene (5-HTTLPR) was recently identified and the presence of the short allele was associated with lower gene expression, lower 5-HT uptake and violent suicidal behavior. Thus, we attempted to determine whether 5-HTTLPR is also involved in the susceptibility to non-violent suicidal behavior. We compared the genotype from 166 West European Caucasians who attempted suicide by a non-violent mean with 139 controls with no history of suicidal behavior from the same ethnic origin. The frequencies of the S allele and the SS genotype in the sample who attempted non-violent suicide were not statistically different to those in the controls. Thus, the genetically altered expression of the 5-HT transporter might be associated with more severe or violent suicidal behavior, but not with non-violent suicidal behavior.