Influence of serotonin transporter promoter variation on the effects of separation from parent/partner on depression

Background Loss of parent during childhood or loss of partner has been associated with adulthood depression. The serotonin transporter polymorphism ( 5-HTTLPR ) has been reported to moderate stress sensitivity reflected for example in the relationship between childhood maltreatment and depression. Therefore, the effect of 5-HTT promoter variation on the relationship between the loss of parent or partner and depression was examined. Method 411 depressive cases and 1347 control subjects from a large well-characterized longitudinal population-based sample of adult Swedes with data on life history and life situation, including psychiatric diagnostic instruments, were studied. Their DNA was genotyped for the mini-haplotype 5-HTTLPR -rs25531. Results Individuals with low 5-HTT activity variants had an increased risk of depression given loss of partner last year compared to those with high activity variants. Conversely, 5-HTT activity variation appeared not to strongly influence the risk of depression given loss of parent during childhood. Limitation Small sample size for those with losses of both parent and partner. Limited power to detect small interaction effects. Conclusion The increased risk of depression given last year loss of partner appeared to be influenced by genetic variation regulating 5-HTT activity. This adds to previous findings of 5-HTT x stressful life events interactions on depression and is in agreement with stronger GxE effects when using objective environmental measures.