This is a study that looks at changes in personality structure in a relatively large sample of the general US population before and after the pandemic. The study has some validity, but also limitations, especially in making attributions to the pandemic, as the changes may be due to other factors. Moreover, the results cannot be generalised to other countries with very different policies regarding the measures taken to combat the pandemic, which have been very different from country to country or even state to state within the US.  

The results show rather small changes whose practical significance is difficult to guess. It is true that the pandemic, and especially the measures taken by each country to combat it, have had effects on mental health. But personality is a relatively stable quality of individuals, and the changes detected in the study seem to be to be expected in a context of major stress such as that experienced in certain periods in 2020 and 2021, and would fit with the detected increase in mental health problems (eating behaviour, self-harm, etc.) observed in the younger population. 

Personality tests assess a person's tendency to show similar behaviours in different contexts. For example, to measure your "extraversion" you are asked whether you tend to talk to others in most situations, whether you are usually sociable, and so on. We may all feel more talkative one day and more reserved another. But a person with high extraversion tends to be talkative or sociable most of the time. 

Therefore, the results of this study, if replicated, could indicate that with the pandemic people changed some of their usual behaviours. Seen in this light, the possible personality changes may not be so surprising. The pandemic was long enough for many of our usual behaviours to change. 

It will be very interesting to see whether, over time, people maintain these changes in their behaviours or whether, on the contrary, the behaviours that were more common before the pandemic return.