Recently, I read a ‘twin study’ on the genetics of mindfulness – and wanted to share the results with you.
First, a little background. Studies on twin siblings have been very important for understanding the genetic and environmental influences on a particular trait or behavior. Twin designs have been used to assess the strength of genetic influence – known as heritability – on all sorts of traits including psychological functioning, height, weight, addiction, sexuality, personality and many others.
Identical twins (who are genetically identical) and fraternal twins (whose genetic similarity is about 50%) are compared. This allows researchers to assess genetic influence without actually doing genotyping (assessing the genes directly). The thinking goes like this: if a trait is entirely genetically driven (the environment has zero effect on the trait) then identical twins will always mirror each other on that particular trait. If a disease was entirely determined by genetic factors, then if one identical twin had the disease, then the other would always have it too. An example: twin studies have demonstrated that if one twin in an identical pair suffers from schizophrenia, the chance that the other twin will be schizophrenic is about one in two – but for fraternal twins, it is only about one in six. That difference – one in two versus one in six – suggests that schizophrenia is at least partially genetically driven.
While many different traits have been assessed using twin designs, mindfulness had never been assessed – until now. Researchers from an esteemed laboratory at King’s College London conducted a study with 2,100 sixteen year-old twins. The findings were quite interesting: they estimated the heritability of trait mindfulness to be about 32% – meaning that while genetics has a substantial effect on one’s level of mindfulness, environmental factors are approximately twice as important in determining one’s level of mindfulness. They also found that some of the same genetic influences associated with depression and anxiety – are also associated with low levels of mindfulness.
Acknowledging that this was just a preliminary study and much more needs to be understood, the scientists write, “Given that adolescence is a period of heightened brain plasticity, mindfulness might be especially useful in depression prevention and treatment in young people by means of improving attentional control.” This will be an important line of research in the future.
Waszczuk, M. A., Zavos, H., Antonova, E., Haworth, C. M., Plomin, R., & Eley, T. C. (2015). A multivariate twin study of trait mindfulness, depressive symptoms, and anxiety sensitivity. Depression and Anxiety, 32, 254-261. [Summary]