The interplay of genetic and environmental factors in shaping well-being across the lifespan: Evidence from the serotonin transporter gene.

BACKGROUND: Converging evidence suggests that well-being plays an important role in promoting and maintaining mental health across the life span. It has been shown that well-being has a considerable heritable component, but little is known about the specific genes involved. METHODS: In this study, we investigated a healthy sample (N = 298) that was genotyped for the serotonin transporter-linked polymorphic region (5-HTTLPR). We hypothesized that 5-HTTLPR gene variation would influence well-being, and additionally investigated interaction effects with age and the environmental influence of early life stress (ELS). RESULTS: Using multiple regression, our results showed a significant three-way interaction between genotype, ELS, and age. Exploration of this interaction showed that young subjects had decreased levels of well-being if they were exposed to ELS and homozygous for the short variant of 5-HTTLPR. This relationship was reversed in old age: subjects that were exposed to ELS and carried the long variant of 5-HTTLPR had decreased levels of well-being. CONCLUSION: Our results indicate that genetic and environmental factors have joint effects on well-being that are susceptible to profound changes across the life span.