Benjamin said that the genetic variants do not determine whether someone develops depressive symptoms, neuroticism or have a poor sense of wellbeing.
“Psychological well-being is jointly influenced by genes and environment,” he said. “The genetic variants that we found account for a small fraction of these genetic associations.”
The scientists found three genetic variants associated with “subjective wellbeing”, how happy or satisfied a person reports feeling about his or her life, based on an analysis of roughly 300,000 people.
The researchers also found two genetic variants associated with depressive symptoms, based on an analysis of nearly 180,000 people, and 11 genetic variants associated with neuroticism, based on an analysis of 170,000 people. The depression results were replicated through an analysis of another sample of nearly 370,000 people.
“We found that most of the genetic variants associated with depressive symptoms and/or neuroticism also were linked to subjective well-being, and vice-versa,” Benjamin said. “When examined individually, each genetic variant explains very little about these traits.
But when taken together, these findings imply that the genetic influences on depression, neuroticism and subjective wellbeing result from the cumulative effects of at least thousands, if not millions, of different variants.”
Same Set of Genes
The study also found that subjective wellbeing, neuroticism and depression are predominantly influenced by the same set of genes. The scientists said this finding indicates that researchers may want to consider studying these traits jointly for future work.
The strongest link was with anxiety disorders. The researchers also found the genetic variants tied to subjective wellbeing, depression and neuroticism moderately overlap with the variants that are associated with schizophrenia and bipolar disorder.
Because the study has found some of the first genetic variants associated with wellbeing, depression and neuroticism, it is too soon to draw conclusions about how the genes affect biological mechanisms, Benjamin said.
The scientists issued several cautions for interpreting the results of their study.
“Genetics is only one factor that influences these psychological traits. The environment is at least as important and it interacts with the genetic effects,” Benjamin said.