Is there an association between serotonin transporter gene polymorphism and family history of depression?

Background: To date, research examining the relationship between the serotonin transporter gene and depression has yielded both positive and negative results. This study will attempt to add further evidence to that body of literature by examining the relationship between the serotonin transporter gene and a family history of depression while controlling for a family history of completed suicide. Methods: Forty-seven volunteers responded to questionnaires regarding family history of depression and suicide, and provided buccal swabs to allow for analysis of the 5-HTTLPR polymorphism. Results: Individuals with the s/s genotype were significantly more likely to have two or more first-degree relatives with a history of depression even when controlling for a family history of completed suicides. Limitations: The small sample size, particularly in the group of individuals with the s/s genotype, is a limitation of this study. Assessment of family history was conducted in abbreviated fashion. Information regarding participants’ personal history of depression and suicide was not collected, so no conclusions regarding participants’ own mental health can be drawn. Conclusions: A significant relationship between family history of depression and the s/s genotype was found, despite the small sample size and while controlling for family history of suicide. Whatever risk short alleles may confer for depression may be distinct from the risk they confer for suicidality.