In this Papers Podcast, Aga Gidziela discusses her JCPP paper ‘Explaining the influence of non-shared environment (NSE) on symptoms of behaviour problems from preschool to adulthood: mind the missing NSE gap’ (https://doi.org/10.1111/jcpp.13729).
There is an overview of the paper, methodology, key findings, and implications for practice.
Discussion points include:
- A definition of non-shared environment and examples of non-shared environmental factors.
- A definition of what is meant by the ‘missing NSE gap’.
- The implications of the finding that school environments do not have a major impact with a shared or non-shared environment when it comes to behavioural problem outcomes in adulthood, and that the strongest predictive processes are in fact genetic.
- How can we narrow the missing non-shared environment gap?
- The implications of the findings for child and adolescent mental health professionals, parents, and teachers.
In this series, we speak to authors of papers published in one of ACAMH’s three journals. These are The Journal of Child Psychology and Psychiatry (JCPP); The Child and Adolescent Mental Health (CAMH) journal; and JCPP Advances.
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Aga is the final year PhD student at Queen Mary University of London in School of Biological and Behavioural Sciences. Aga’s research focuses on investigating developmental changes in the genomic prediction of behaviour problems during childhood and adolescence and identifying environmental factors that combine with genetic propensity to result in the development of variation in neurocognitive skills and behaviour problems.
- Featured paper ‘Explaining the influence of non-shared environment (NSE) on symptoms of behaviour problems from preschool to adulthood: mind the missing NSE gap’, (2022). Agnieszka Gidziela, Margherita Malanchini, Kaili Rimfeld, Andrew McMillan, Angelica Ronald, Essi Viding, Alison Pike, Kathryn Asbury, Thalia C. Eley,S ophie von Stumm, Robert Plomin
[00:00:07.530] Jo Carlowe: Hello, welcome to the Papers Podcast series for the Association for Child and Adolescent Mental Health, or ACAMH for short. I’m Jo Carlowe, a Freelance Journalist with a specialism in Psychology. In this series, we speak to authors of papers published in one of ACAMH’s three journals. These are the Journal of Child Psychology and Psychiatry, commonly known as JCPP, the Child and Adolescent Mental Health, known as CAMH, and JCPP Advances.
Today, I’m interviewing Aga Gidziela, PhD student at Queen Mary University of London, in the School of Biological and Chemical Sciences. Aga is the first author of the paper, “Explaining the Influence of Non-Shared Environment (NSE) on Symptoms of Behaviour Problems from Preschool to Adulthood: Mind the Missing NSE Gap,” recently published in the JCPP. This paper will be the focus of today’s podcast.
If you’re a fan of our Papers Podcast series, please subscribe on your preferred streaming platform, let us know how we did, with a rating or review, and do share with friends and colleagues.
Aga, thank you for joining me. Welcome. Can you start with an introduction about who you are and what you do?
[00:01:19.710] Aga Gidziela: Hello and, first of all, thank you for inviting me to the podcast. So, as you said, my name is Aga and I’m a final year PhD student at Queen Mary. I’m interested in how genes and environment contribute to the development of behaviour problems in children and adolescents. My work also focuses on how nature, that is our DNA, and nurture, which is our environment, interact and work together to influence the co-occurrence between specific behavioural problems, such as, for example, the co-occurrence between hyperactivity and conduct problems.
[00:01:53.450] Jo Carlowe: Great, thank you very much. So, today, we’re going to be looking at your paper, “Explaining the Influence of Non-Shared Environment (NSE) on Symptoms of Behaviour Problems from Preschool to Adulthood: Mind the Missing NSE Gap,” recently published in the JCPP. Aga, before we go into the detail, can you give us a quick definition of non-shared environment, ideally, to include some examples of non-shared environmental factors that typically arise?
[00:02:20.790] Aga Gidziela: Yes, absolutely. Both the non-shared environment is next to genes and the shared unfriendly environment, the third factor that contributes to differences between siblings and twins. It is basically what makes identical twins, growing up in the same family, different from each other. Because, as we know, identical twins share close to 100% of their genes, and they also share their family environment.
So, while some home setting and parenting are thought to be the shared environmental component, examples of the non-shared environment can, for example, include different classroom experiences, different peer group environments, or even different parenting than the twins receive within the home.
[00:03:06.650] Jo Carlowe: Aga, can you give us a definition of what is meant by the missing NSE gap?
[00:03:12.599] Aga Gidziela: Yes, of course. So, the missing NSE gap is an analogy to the missing heritability gap. So, I feel I should explain that one first. So, missing heritability gap, it refers to the shortfall in identifying the specific genes that account for the heritability of the trait. The classical twin design allows us to decompose the variants in particular trait. For example, behaviour problems, intergenetic, shared environment, and non-shared environment components.
So while, for example, heritability of a specific behavioural problem can be 60%, genetic studies find it very difficult to find specific genes that can account for the 60% of the variants, without modifying the very minor effort sizes. So, missing non-shared environmental gap now refers to the fact that non-shared environmental component which is, for example, 40% for a specific behaviour problem. But with specific environment, we only account for a very modest proportion of variants. So, this is an analogy that we cannot – we struggle, as Researchers, to find the specific environmental and genetic factors that account for a large proportion of variants in these behavioural problems, and other traits.
[00:04:26.889] Jo Carlowe: Brilliant, and that’s super helpful, thank you. Let’s look at the paper itself. Can you start with an overview of what you looked at and why?
[00:04:35.150] Aga Gidziela: Yes, so, in the paper, me and my colleagues explored to what extent these individual differences in behavioural problems in children and adolescents are influenced by these specific non-shared environments, such as, for example, early life adversity, different parenting styles or, as we mentioned, the classroom environment.
We wanted to measure the role of this non-shared environment alone independently of the contribution of genes, and the shared environment. And we were especially interested in how these environments, reported by parents, from age three and through to age 16, relate to behavioural problems that are reported by our participants, that is the twins, at age 21.
[00:05:21.900] Jo Carlowe: And can you tell us a little about the methodology that you used for this study?
[00:05:26.680] Aga Gidziela: Yes, of course. So, as I mentioned, our participants were twins. So, we enrolled twin pairs that were participants of the Twins Early Development Study, TEDS for short, for whom environmental and behavioural data was collected throughout their development.
In the study, we first used the classical twin design, that estimates the extent to which individual differences in behavioural problems are due to genes, shared environment, and the non-shared environment, that is the focus of the paper. And then we used the multivariant twin design that allowed us to estimate how much of these individual differences in behavioural problems are due to the specific environment, that is earlier specific environmental factors, such as, for example, parenting styles, or early life adversity.
[00:06:16.960] Jo Carlowe: And what key findings from the paper would you like to highlight?
[00:06:21.470] Aga Gidziela: In the paper, we found a large gap between the individual variants in behaviour problems that is explained by specific environmental factors, and the total non-shared environmental variants that we found out by combatting the classical twin design study in the first place.
What it means is that while the twin design allowed us to decompose these individual differences in behavioural problems into genetic, shared environmental, and non-shared environmental influences, we failed to find specific environmental factors, such as the home or classroom environment, that could account for these total non-shared environmental variants. The gap between the two was very large.
[00:07:04.580] Jo Carlowe: In your conclusion in the paper, you state that school environments do not have a major impact, whether shared or non-shared environment, when it comes to behavioural problem outcomes in adulthood. And the strongest predicted processes are, in fact, genetic, but what are the implications of that finding?
[00:07:24.430] Aga Gidziela: So, I mean, further implication is that these findings remind us that the widely explored correlations between specific environments and symptoms of behavioural problems, should not be assumed as caused by environmental predictive processes. The fact that these associations between environments and behavioural problems are about 50%, mediated genetically, highlights the importance to control for genetic influences when trying to find specific environments influencing developmental behavioural problems.
[00:07:57.590] Jo Carlowe: And in the paper, you say the major question raised by your research is, how can we narrow the missing non-shared environment gap? Aga, what suggestions do you have for this, and it would be really helpful if you could, sort of, explain it in lay terms?
[00:08:13.370] Aga Gidziela: Narrowing down the missing non-shared environment gap will require advances in how these environments are measured in the first place. So, one solution could come from technological advances in real time, and biological and behavioural monitoring, using, for example, smartwatches and smartphones, as well as devices that could measure social media activity. These new methods can offer a much more precise and unbiased measurement of the environment, but they do not come without another challenge, which is making sense of these huge datasets that will need machine learning solutions.
[00:08:48.970] Jo Carlowe: And what are the implications of your findings for CAMH professionals and for parents and Teachers?
[00:08:56.040] Aga Gidziela: So, it is important to remember that the non-shared environment is the way the environment works to affect symptoms of behaviour problems, not just for twins and siblings, but for all children. And although we did not find large non-shared environment effects on behaviour problems, the affect sizes were not zero, which means that parenting style, home, and classroom environments do matter and they are associated with development of symptoms of behaviour problems in children and adolescents.
It is important to know that our results are limited to the normal range of environmental differences and not generalised to environmental extremes, such as neglect, abuse, or catastrophic events, which, according to some research, may generate stronger effects of non-shared environment.
[00:09:44.390] Jo Carlowe: Hmmm, yeah, that’s really helpful to highlight that. Aga, is there anything else in the paper that you’d like to highlight?
[00:09:49.130] Aga Gidziela: We would like our results to be seen as a challenge to Researchers to account for more of the non-shared environmental variants in behavioural problem symptoms. After controlling for these genetic and shared environmental influences, our goal is to identify the environments that predict symptoms of behaviour problems, which is a prerequisite to more advanced investigations, to explain the mechanisms underlying these associations.
[00:10:15.690] Jo Carlowe: And are you planning any follow-up research or is there anything else in the pipeline that you’d like to share with us?
[00:10:22.600] Aga Gidziela: So, when conducting the study, we selected several environmental candidates for our analysis, which included early life adversity, parenting style, home, and classroom environment. Initially, we had hundreds of environmental variables available in the test dataset. So, our next research project will explore how these selected environments interact with genetic risk, to explain individual differences in developmental psychopathology in adolescents.
This basically means that we will combine these environmental measures and genetic factors to find out whether their interaction can tell us more about individual differences in developmental psychopathology than both of these factors alone.
[00:11:06.089] Jo Carlowe: Right, what’s the timescale on that study?
[00:11:08.300] Aga Gidziela: Oh, we’re planning to finish next year.
[00:11:10.960] Jo Carlowe: Okay, great. Aga, finally, what is your take home message for our listeners?
[00:11:15.700] Aga Gidziela: I would like to say that the non-shared environment it’s important in disentangling individual differences in behavioural problems, because it accounts for more variants than nature and nurture, which is one of the most consistently replicated findings from genetic research. So, the challenge for now is to find which environments can actually account for these huge variants that we can explain anonymously, using the classical twin design.
[00:11:41.589] Jo Carlowe: Brilliant. Aga, thank you ever so much. For more details on Aga Gidziela, please visit the ACAMH website, www.acamh.org, and Twitter @acamh. ACAMH is spelt A-C-A-M-H, and don’t forget to follow us on your preferred streaming platform, let us know if you enjoyed the podcast, with a rating or review, and do share with friends and colleagues.