The purpose of this study was to investigate the effect of the COVID-19 pandemic on the mental health of children and the effect of parental involvement during the pandemic. We used longitudinal observational data from a large sample of the ABCD Study. A total of 4885 children were analyzed in the study, adjusted for PMQ scores, and then analyzed for changes in CBCL scores before and after the onset of the pandemic. Our findings suggest that the COVID-19 pandemic has a minor adverse effect on children’s mental health. We also found that the degree of involvement between the child and the parent and parenting style affects a child’s mental health even in the face of the pandemic. For each, we will interpret the results obtained below.

First, we hypothesized that mental health problems in children would worsen over time due to the COVID-19 pandemic. The study results support our hypothesis. The emotional problem exacerbated by this pandemic was depression. This finding is consistent with previous studies and shows that depressive symptoms in children are exacerbated by the COVID-19 pandemic30,31,32,33,34,35, as is the case in adults35,36,37. However, the withdrawn/depressed behavior went from an average of 53.4 ± 5.7 pre-pandemic to 53.7 ± 5.9 since the onset of the pandemic, which is a change of only 0.3. Additionally, these values from before and during the COVID-19 pandemic are in the normal range. While the worsening of depressive tendencies for children was statistically significant, the magnitude of deterioration was clinically minor; hence, caution is warranted in the interpretation of these results. Next, this change was similar for attention, which worsened albeit only slightly clinically; the average attention problems went from 53.4 ± 5.4 pre-pandemic to 53.6 ± 5.6 since the onset of the pandemic. Interestingly, the results of our study did not uncover any effects on anxiety or physical complaints. Previous studies have reported that the COVID-19 pandemic does not exacerbate children’s emotional problems38,39. Rather, emotional problems of children aged 11–16 reportedly diminished in the United Kingdom38. A longitudinal study of about 1000 children in England reported a fair reduction in anxiety overall39. These results are consistent with our findings that the COVID-19 pandemic has no effect on children’s anxiety. Moreover, our findings showed that children’s behavioral problems were unaffected by the pandemic. This result is consistent with the findings of an online cross-sectional study of 1264 children (aged 2–6) and their parents in two primary schools in Hubei, China40. Hence, mental health problems, such as anxiety and behavioral issues commonly observed in children, seemed to be largely unaffected by the pandemic.

Additionally, we investigated whether there were differences in mental health changes between children who had already experienced severe symptoms prior to the pandemic and those who did not. Interestingly, if the mental health symptoms were initially severe, all mental health symptoms improved significantly during the pandemic. This improving trend might be a regression to the mean. Thus, it should be interpreted with caution. Nevertheless, this finding may indicate that children who initially had interpersonal problems moved away from the community, reducing their interpersonal problems and improving mental health. The previous study reported that children perceive home isolation positively rather than negatively, which reduces psychological distress and increases life satisfaction41. In contrast, children who did not exceed the cutoff before the pandemic had worsening mental health during the pandemic, excluding rule-breaking behavior. The interaction between lifestyle changes and the psychosocial stress of staying at home may further exacerbate the adverse effects on children’s mental health39. However, the change in the t-score of CBCL was less than 1 point at maximum. Considering that the t-score is in the normal range, the pandemic may have hardly affected children whose mental health was initially stable. Most children have functioned at the same or higher levels since the pandemic and are satisfied with their current living conditions41.

Subsequently, we verified the hypothesis that parental involvement serves as a protective factor for a child’s mental health even during the pandemic. Parental involvement positively affected children’s mental health, emotional, and behavioral aspects. In particular, when parents and their children engaged in frequent conversations and parental understanding of their child’s condition was high, rule-breaking decreased; when such involvement was weak, the child’s depression and aggressive behavior increased. A cross-sectional study of 1655 parents and children in China found that parental attitudes and intimacy with children are positively correlated with the child’s mental or behavioral health21. These results are consistent with those of our study, which shows that parental child-rearing styles have a crucial impact on children’s mental health. Our study is a large longitudinal study of children living in the United States, which has the highest number of COVID-19 infections42. As far as we know, it is the first time that parental involvement has been shown to influence the mental health of children in the United States. During home confinement, children generally interact the most with parents and caregivers; so early detection and care of children’s mental health problems can prevent deterioration43. This finding may demonstrate that parents and caregivers impact their children’s mental health.

In particular, on analyzing each PMQ sub-item, it is found that less rule-breaking occurs when children communicate clearly with parents about their plans for school or activities with friends. In contrast, less disclosure is associated with increased depression. In other words, it might be necessary for parents and children to communicate frequently and fully about their daily lives, not merely about the negative aspects. Frequent conversations about the pandemic and expressions of unpleasant emotions affect externalizing and internalizing symptoms in children44. Rumination was positively associated with depressive symptoms in children aged 9 and 1245. Those who were not optimistic about the onset of a pandemic were at higher risk of depressive symptoms than those who were46. Therefore, encouraging parents to communicate more fully with their children and consider the positive aspects may prevent deteriorating mental health during the pandemic.

While our findings bring great benefits to this area of study, our research has limitations. First, we set March 1, 2020, as the start date of the COVID-19 pandemic, and analyzed those subjects who consented to provide third-year follow-up data from March 1, 2020, onwards. However, the period from March 1, 2020, to the date of actual data acquisition varies by subject, that is, the impact of the duration of the pandemic at the point of data collection has not been considered. In addition, whether there were various restrictions such as lockdowns and social interactions during these periods may vary depending on the area in which they live. The impact of the pandemic on children’s mental health may differ between the early stages of the pandemic and the stages of progress and recovery. In the future, it may be necessary to consider accumulative data across time included the mechanism. Second, we examined whether there was a difference between those participants with and without third-year data. We found that those without third-year data had slightly higher CBCL scores. Therefore, if the analysis had included people who withdrew from the study, overall child mental health may have been somewhat improved. Third, children’s mental health was investigated using the parent’s assessment, and the degree of parental involvement was investigated using the children’s assessment in this study. In the future, both child and parental reports should be included to ensure data accuracy.

In conclusion, the results of this study indicate that the COVID-19 pandemic may slightly exacerbate depression and attention problems in children. On the other hand, if the mental health symptoms were severe before the pandemic, all mental health symptoms improved during the crisis. Additionally, even during the global public health crisis caused by COVID-19, positive parent–child relationships have a protective impact on pubescent children’s mental health in the United States. Therefore, increasing parent–child involvement is critical to children’s overall mental health even during the COVID-19 pandemic.