Association between serotonin transporter gene promoter polymorphism and suicide: results of a meta-analysis

There is strong evidence supporting a role for serotonin system dysfunction in the pathology of suicidal behavior. Many studies have examined the association between a functional polymorphism of the serotonin transporter gene promoter (5-HTTLPR) and suicide but have yielded inconsistent results. Our goal here, by analyzing the cumulative data from primary literature, was to determine conclusively whether there is an association.

Three meta-analyses were performed. One compared the 5-HTTLPR polymorphism between suicidal subjects and normal control subjects; another compared suicide attempters with nonattempters of the same psychiatric diagnoses; the last one compared either violent or nonviolent suicidal subjects with normal control subjects.

We found no association between 5-HTTLPR polymorphism and suicidal behavior (p =.379). When we compared subjects with the same psychiatric diagnoses, the genotypes carrying the s allele were significantly more frequent in suicide attempters than in nonattempters (p =.004). In addition, the s allele was associated with violent suicide (p =.0001) but not with nonviolent suicide (p = 1.00).

Our results provide significant evidence supporting the association of the s allele of 5-HTTLPR polymorphism with suicidal behavior in the psychiatric population, also with violent suicide. These support a role for decreased serotonin transporter function in the vulnerability to suicide in a select population.