A study by UCLA researchers in the current edition of Biological Psychiatry shows that for people with the short version of the 5-HTTLPR gene, a variation linked to predisposition for depression, having a supportive, loving family early in life significantly reduces the chance of becoming depressed later in life.
Saliva samples of 118 young adult subjects were taken to determine their 5-HTTLPR genotype. Subjects also completed assessments related to depression, current stress and their childhood family environment.
Results showed that genetic variation alone did not predict a person's probability of developing depressive symptoms. This depended instead upon a combination of genetic and environmental factors, with a stressful family environment showing a strong relation to depressive symptoms. In comparison to others, individuals with the genetic variation linked to depression were more likely to suffer from it if they had recently experienced stress--but less likely to develop it if they reported a positive early family life.
These findings suggest that rather than serving as a predictor for depression, the 5-HTTLPR gene is instead "highly responsive to environmental influence" and emphasize the importance of a nurturing home life to mental health.