Although we know that both our genetic makeup and our environment play an important role in who we are and what we become, scientists have long debated as to which aspect plays the larger one (Serpell, 2013). In the mental health field, scientists maintain that in order for a mental disorder to be expressed an individual must have a genetic predisposition toward a condition, coupled with an environmental stressor (Rutter, 2003). In today’s article, I’d like to use this debate to focus our conversation on anxiety.
First let's talk about the heritability of anxiety. So how do scientists test this? Well, funny enough, one of our best resources is studying identical twins. Genetically speaking, identical twins are… well…. Identical. In fact, the differences between them are theorized to be purely the result of differences in environmental experience Sahu & Prasuna, 2016). In several studies conducted on the body’s hormonal stress response amongst twins, it was shown that the dynamics of the cortisol (stress hormone) effects were moderately heritable (Ising & Holsboer, 2006). In additional twin studies it was found that genetics contributes to between 30-50% of your risk for developing an anxiety disorder (Gottschalk & Domschke, 2017; Shimada-Sugimoto et al., 2015).
Like most things in science, the heritability of something as amorphous as anxiety is quite complex. Many different gene variations interact together to predispose someone to illness. This is in part, why there is so much variation to heritability: each person may have a different combination of gene variations that predispose them to anxiety at different degrees. Recent innovations in genetic testing have allowed scientists to begin studying genes linked to anxiety. I won’t bore you with the list here, but most of them have to do with the production and signaling pathways of neurotransmitters (such as serotonin; Ising & Holsboer, 2006).
Join us in here where we will break down how environmental factors can influence the expression of anxiety!