A paper by Dr Kaili Rimfeld and many other TEDS researchers, looked at how the advent of the COVID-19 crisis and the initial lockdown in March 2020 psychologically affected young-adult twins in Great Britain. 

Over 4000 TEDS twins were assessed one month after the first lockdown (T2) in 30 psychological and behavioural traits such mental health, wellbeing, relationships, behaviours, thoughts and attitudes, as well as life changes, home environment and changes in physical health. These results were compared to responses of the same traits assessed in 2018 (T1). 

Contrary to initial thoughts, on average, changes in these diverse traits were relatively small a month after lockdown and just as many changes were in a positive as negative direction. Results showed that some aspects of life improved, most notably, verbal peer victimisation. This could be explained by a decrease in social interactions, particularly in-person during the lockdown. The largest negative changes included reduced volunteering. This could be explained by there being fewer opportunities to volunteer during lockdown and reduced achievement motivation, which is worrying as this generation is the next generation of workers. Additionally, we saw an increase in hyperactivity and inattention, which seems to fit with reports that people find it harder to concentrate during lockdown. 

Our genetic analyses indicated that these diverse psychological traits were equally heritable in T1 and T2, both showing average heritability of 32%. This indicates that about a third of individual differences in these diverse measures can be explained by inherited DNA differences. The rest of the individual differences were explained by environmental factors, unique to every individual, that is not shared by twins growing up in the same family. Interestingly, a modest proportion of the change in these diverse psychological measures was also explained by genetic factors, with heritability around 15%. The remaining individual differences were again explained by unique environmental factors. 

We concluded that the COVID-19 crisis, after one month of lockdown, did not fundamentally change these young people psychologically. Importantly, this is not to dismiss the pain some of them felt before or during the crisis, or will continue to feel after the crisis ends, it just means that on average, the TEDS twins felt much the same as usual at this time.  It is possible that the COVID-19 crisis and further lockdowns throughout 2020 will have a greater effect down the line, so it will be interesting to see if this is the case in the follow-up survey results from July and October 2020.