Having anxiety can make us feel out of control and totally alone. However, research suggests that we may not need to look much further than our own family trees to find other people dealing with the same issues, because we could have inherited a lot of those anxious tendencies.
In the study, published online this week in the Proceedings of the National Academy of Sciences, researchers mildly stressed out 592 young rhesus monkeys by having an experimenter intrude into their space without making eye contact. Then, each subject underwent positron emission tomography brain scans (PET), which monitor metabolism in specific mood-related brain areas. The researchers also monitored the monkeys' behavioral responses to the situation.
The monkeys also underwent another kind of brain scan that allowed researchers to look at the anatomy of each brain and compare it to the rest of their family tree.
Results showed that the monkeys that reacted more strongly to the anxiety-producing situation — by freezing up or becoming less communicative — were also more likely to show overactive metabolism in those brain scans, indicating that the circuit was working overtime. Those anxious monkeys often inherited this type of brain function from their ancestors.
The researchers also found that certain variations in those anxiety-related brain structures could be inherited, but it was this specific overactive brain metabolism that lead to more anxious behavior, rather than the structures themselves. The study authors concluded that variations in metabolism in these areas "regulate, initiate, and enact anxiety-related behavior that, when passed down from parent to child, likely result in early-life anxiety."
Yes, these were monkeys in the study, but we humans can also show this anxious temperament as kids, and this research suggests that the way those brain circuits are working may make a huge difference. It's important to note that this isn't necessarily a measure of our overall anxiety. Instead, a temperament is more of an approach to the world that includes the way we react to new or frightening situations. Although having an anxious temperament predisposes us to develop more serious anxiety disorders later, it doesn't seal our fate.
Overall, family history accounts for about 35% of the likelihood that we'll develop an anxiety disorder — that's in addition to environmental factors, like the way your parents interacted with you. So, you can blame your family (and their genes) for a bit of your anxiety, even if you're more human than monkey.