Untangling the link between school achievement and mental health: What part do your genes play?

Imagine this: you’re back in school, your teacher is pacing the classroom handing back marked exams, and places yours on your desk. In big red letters, you see the word: FAIL. How do you feel? Perhaps you want to hide away for a while and process your feelings alone. Or perhaps you want to shout at your teacher for marking you unfairly.

But what if I told you that how you react may be influenced by how well your parents did at school? In our new study, we looked at how genetics might link school achievement to different mental health difficulties.

What we (don’t) know about the link between education and mental health

Previous research has suggested that having parents with better school achievement means that you are less likely to suffer with mental health difficulties. But, as you might expect, this is not a straightforward connection. We could break this down into the classic argument of ‘nature versus nurture’:

But past research has rarely considered an important third route, where the environment parents provide is also influenced by their genetics. Let’s imagine a parent with genes that contribute to higher educational attainment. They pass on around half of these genes to their children. But the other half might still affect their child; their genes may make them more likely to encourage their children’s attainment, maybe by having more books or reading more to their children. This indirect effect of parental genetics is termed genetic nurture.

So far, we have also overlooked the fact that children can have very different mental health difficulties. In general, some children may withdraw, becoming anxious or depressed (termed internalising problems). Some might lash out, becoming aggressive or disruptive (termed externalising problems). The way your genes affect these different aspects of mental health is not clear.

What did we do?

In our recent study, we investigated genetic nurture in the link between educational attainment and internalising/externalising mental health difficulties. To do so, we used the genetic data of 3,228 parent-offspring trios from the Millennium Cohort Study. This study also measured children’s internalising and externalising problems using parent reports when children were aged 3, 5, 7, and 14 years.

To assess the possible effect of mothers’, fathers’, and children’s genes for educational attainment, we calculated their ‘polygenic scores’. These scores represent the number of genetic variants (small differences in the coding of genes) they possess that have been suggested to contribute to the years they spend in education.

We then used these scores to predict children’s internalising and externalising difficulties. Importantly, we used a new method to look only at influence of parents’ genes that were not passed down to children, but may influence them via their environment (genetic nurture).

What did we find?

1. Fathers with genetics that help their educational attainment created environments that protected against child internalising

First, we looked at whether fathers’ polygenic scores could indirectly predict their children’s internalising and externalising problems. Interestingly, having higher polygenic scores for educational attainment predicted fewer internalising difficulties in their children at ages 3-14.

This means that fathers with genetics that helped their educational attainment created an environment that tended to reduce difficulties such as anxiety and depression in their child.

2. Mothers with genetics that help their educational attainment created environments that protected against early child externalising

Second, we looked at the indirect effects of mothers’ polygenic scores on their children’s internalising and externalising problems. In contrast to the fathers’ effect, having higher polygenic scores for educational attainment predicted fewer externalising difficulties in their children at ages 3 and 5.

This means that mothers with genetics that helped their educational attainment created an environment for their child that tended to reduce difficulties such as aggression and disruptive behaviours in early years.

What can we take away from this research?

We have shown that parents’ education-related genetics may influence the environment they create for their children, which can affect their child’s mental health outcomes. This important ‘genetic nurture’ effect may have been overlooked by past research that has focussed on the direct influence of your genetics on your outcomes.

The source of this effect for different mental health difficulties seemed to come from different parents. Without further research, we can’t be sure why mothers’ polygenic scores predicted child externalising while fathers’ predicted child internalising. But this is an important guide for future studies: we must consider different mental health outcomes to fully understand their genetic link to educational attainment.

How can we apply our results?

We revealed an intriguing direction for mental health interventions. Namely, we highlight parents as a potential target for educational and mental health support in at-risk families. For instance, we might investigate the effect of training parents to create environments that optimise child learning and wellbeing.

Although, it is very important to note that having a low polygenic score for educational attainment does not mean child mental health difficulties are inevitable. Instead, on average, parents with higher polygenic scores are more likely to have children with slightly fewer mental health problems. We cannot currently predict behaviour from polygenic scores. Overinterpreting results from polygenic analyses can have dangerous implications.

What could we have done better?

A more reliable measurement of child mental health would be to include child and teacher reports, rather than parent reports alone. Parents might struggle more to identify internalising symptoms in children than more obvious externalising behaviours.

It is also important to investigate whether our results can be generalised to different ancestral samples. We looked only at a sample of European ancestry, which might have different genetic factors and educational/mental health outcomes to other populations.

References

Connelly, R., & Platt, L. (2014). Cohort profile: UK millennium Cohort study (MCS). International journal of epidemiology, 43(6), 1719-1725. https://doi.org/10.1093/ije/dyu001

Early Years Alliance. (2021, December 13). Family learning, parenting and School Readiness . early years alliance. Retrieved April 18, 2023, from https://www.eyalliance.org.uk/family-learning-parenting%C2%A0and-school-readiness%C2%A0

Erickson, J., El‐Gabalawy, R., Palitsky, D., Patten, S., Mackenzie, C. S., Stein, M. B., & Sareen, J. (2016). Educational attainment as a protective factor for psychiatric disorders: findings from a nationally representative longitudinal study. Depression and anxiety, 33(11), 1013-1022. https://doi.org/10.1002/da.22515

Harden, K. P. (2021, September 12). Kathryn Paige Harden: ‘studies have found genetic variants that correlate with going further in school’. The Guardian. Retrieved April 22, 2023, from https://www.theguardian.com/science/2021/sep/12/kathryn-paige-harden-psychologist-genetics-education-school

Kong, A., Thorleifsson, G., Frigge, M. L., Vilhjalmsson, B. J., Young, A. I., Thorgeirsson, T. E., Benonisdottir, S., Oddsson, A., Halldorsson, B. V., Masson, G., Gudbjartsson, D. F., Helgason, A., Bjornsdottir, G., Thorsteinsdottir, U., & Stefansson, K. (2018). The nature of nurture: Effects of parental genotypes. Science, 359(6374), 424–428. https://doi.org/10.1126/science.aan6877