Tegan Taylor: So, almost all of us experience some kind of stress or trauma in our lives, so why does it trigger mental health issues in some people but not in others? Some people do have genes that predispose them to mental illness (we were just talking about genetic testing) but our experiences play a part too, and in recent years researchers have been exploring that relationship between mental health and epigenetics, which is how the genes we inherit are controlled and expressed. Divya Mehta is one of those researchers. She has been looking at how environmental health factors like social support and exercise influence our gene activity and therefore our mental health. Welcome, Divya.
Divya Mehta: Thank you, Tegan, for having me today.
Tegan Taylor: So, Divya, if all of us are experiencing similar levels of trauma and stress across our lives, and of course there are some people who have much more trauma than others, but on the whole most of us have the same, what makes us respond so differently?
Divya Mehta: So, people respond differently to stress due to their individual biological, psychological and social risk and protective factors. In terms of biological factors, there is the underlying genetic vulnerability, so the DNA code that we inherit from our parents, as you mentioned. But there is also epigenetics. These are changes in gene activity due to environmental and lifestyle factors. So it’s really a combination of these different factors that makes people respond differently to stress.
Tegan Taylor: So this is a really complex topic. You’ve got someone’s genetics, you’ve got things that are happening in their lives, and maybe there is a gene expression associated with that. How do you actually study something as complicated as this?
Divya Mehta: So, as I said, the DNA code is what we inherit from our parents. This does not change. But what does change throughout our lives is the activity of our genes. And these changes in gene activity can impact our health. So gene activity can go up and down in response to environmental factors called epigenetics, as I mentioned. Now we can collect biological samples from people, so by looking at saliva or blood or a cheek swab, we can run these in the lab and we can measure a person’s gene activity across the entire genome at different time points and in response to different environmental factors. So, really kind of getting a map of a person’s entire life and different risk and protective factors that happened to them will explain gene activity changes and how this affects our mental and our physical health.
Tegan Taylor: And so when you are taking these swabs, they are showing a different map at different points in time, are they?
Divya Mehta: Yes, so when we take a swab, we run it on a microarray, and the microarray measures over 850,000 sites in the genome. So this is across all the known human genes that we have, and all of us have the same genes essentially but the activity can differ. So, for instance, before and after breakfast or before and after exercise or before and after stress exposure, activity of genes changes, and this can be measured in real time using these microarrays in the lab.
Tegan Taylor: So, you found quite an interesting way of controlling for…checking someone before and after stress exposures. You looked at students who were studying to be paramedics, and you look at them at the beginning of their course and then after they would have had to go out with the ambulance and presumably be exposed to a stressful situation.
Divya Mehta: Yes, so most of the research so far has looked at biological outcomes of stress at a single time-point, and this is quite problematic due to many reasons. When we look at a single time-point we cannot distinguish what are the causes and what are the consequences of stress exposure. And the focus has really been on the negative impacts of stress. So a lot of my research has looked at post-traumatic stress disorder, depression, et cetera. But a lot of us remain resilient and some people experience post-traumatic growth after experiencing stress. So our study looks at biological and health outcomes before and after exposure to stress among paramedical students. This is really important, because by using such a method we can identify which of the genes are altered as a result of exposure to stress, and we can also understand what are the social and the psychological factors that drive these changes.
Tegan Taylor: Right, so you can’t change your DNA but you can change some of these environmental factors. What factors did you find were the most protective?
Divya Mehta: So, our research has demonstrated that certain social and psychological factors are highly beneficial and act as a buffer, and these reduce some of the negative outcomes of stress on our genes. For example, individuals who have experienced high levels of social support and those who have a strong sense of connectedness and belongingness, this could be to a group, a team or an organisation, these individuals cope much better with stress than those who remain socially isolated.
Tegan Taylor: So you’ve got your social connections, that makes sense, but you’re saying that having a sense of identity or as part of a group, even if you are not physically with them is also protective.
Divya Mehta: Yes, absolutely, so being part of the group, being part of an organisation is some form of identity, as you mentioned and also empowerment. So that itself gives you some kind of a team or an organisation or a community support and this is very beneficial psychologically, and what we see biologically as well.
