As of mid-December 2021, more than 27 million people worldwide have been diagnosed with pneumonia caused by COVID-19, resulting in more than 5.37 million deaths (1). In most countries severely affected by the pandemic, governments have taken measures to impose lockdowns and restrictions on outings to deter the uncontrolled spread of the virus, limit infections and deaths, and reduce the pressure on healthcare systems and healthcare providers. In the United States, most states and counties began implementing the lockdown policies in late March 2020, which were adopted by the local governments to reduce the spread of the virus under the pressure of unpredictable uncertainties posed by the pandemic (2).

In this study, what we concern about are the lockdown policies including stay-at-home orders, quarantine, social distancing, and isolation of confirmed patients associated with high risk. Studies have shown that government administration and public cooperation do lead to better control of pandemics like COVID-19 (3, 4). However, such lockdowns directly lead to reduction in social interaction and have negative impacts on individuals' mental health (5). For example, not only do people experience increased anxiety and stress about future income and employment (6), but they also face an immediate fear of infection, for themselves, their family or friends (7). Factors such as the incubation period of a pandemic and the time required for isolation may also lead to anxious emotional reactions (8). Restrictions on activities, loss of daily life and reduced social activities also result in feelings of boredom, depression, and isolation (9).

Numerous studies have shown that the COVID-19 pandemic caused severe psychological problems in the population (10–12), and we focused our research on the impact of lockdown policies on mental health. Existing research has explored the psychological effects of lockdown at the individual level and demonstrated that the mental health of individuals is influenced by a number of factors, such as work status, income, gender, and relationship status (13), as well as the length of lockdown, how and where they are imposed (14). Scholars have also found that lockdown affects different individuals in different ways and to different degrees. Many of them have compared the level of various mental health indicators measured in cross-sectional surveys conducted in the general population (15), Child (16), adolescents (17), adults (18), older adults (19), new mum (20), university students (21), and college students (22). For example, Yildirim (19) identified the psychosocial status, attitudes, and experiences of individuals aged 65 and older confined in their homes during the COVID-19 outbreak in Turkey, and concluded that lockdown applied specifically to older adults forced them to establish new routines and made them aware of some values; however, they asserted that they were stigmatized and isolated, their fear of COVID-19 increased, and they were treated unfairly. Olson et al. (22) conducted a photographic survey of college students' experiences during lockdown and found that students frequently reported deterioration in mental health. Non-academic aspects of students' lives, such as work and home environments, contributed significantly to perceived stress.

However, from a higher perspective, the lockdown policies developed by policymakers must have had a significant impact on individuals' mental health, and we argue that the interregional heterogeneity of such policies is an important but currently overlooked key factor. In this study, we discuss the impact of lockdown policies on overall American mental health at the state level, to provide policy recommendations for state governments to balance lockdown policies and individuals' mental health during the COVID-19 pandemic. Stress process theory suggests that adequate resources (e.g., high-quality social support) can prevent or mitigate the effects of stress on mental health (23–25). In particular, economic support as a positive intervention can reduce the impact of negative events on individuals, and therefore we consider the possible impact of government economic support policies on mental health.

We investigate such impact based on the statistical analyses provided by the Household Pulse Survey and the Oxford Covid-19 Government Response Tracker (OxCGRT) from 23 April 2020 to 30 August 2021. To our knowledge, this is probably one of the first study to track the mental health-related effects of state government lockdown policies at the macro level. Compared to other short-term studies at the individual level, our study better conveys the true effects of the “lockdown,” with the aim to provide a theoretical consideration for improving the adverse effects of lockdown policies on mental health and to contribute practical implications for improving individuals' mental health during the lockdown period.

The aim of this study is to examine the impact of the intensity of the lockdown policies imposed by the state governments on the mental health of U.S. individuals during the COVID-19 pandemic. We investigated our analyses based on the following two questions: (1) do government lockdown policies lead to a worsening of individuals' mental health? (2) to what extent does the relationship between lockdown policies and mental health vary across states depending on the level of government economic support? Specifically, we find that government lockdown policies are associated with increases in post-lockdown estimates of depression and anxiety disorders across states. Depending on the spread and infection of COVID-19, state governments have implemented different levels of lockdown policies. The most common types of lockdown are those requiring self-isolation and home quarantine of patients and close contacts, even urban closures in areas with severe outbreaks. Lockdowns appear to be the most effective way to deteriorate the spread of the virus, but it can lead to very serious mental health problems. It is well-documented that lockdowns trigger anxiety and insecurity (34, 35) and alter sleeping habits. During the lockdown, people sleep later than usual, stay in bed longer and sleep poorly (36). At the same time, anxiety and insecurity may be exacerbated by concerns about economic stress and major changes in daily life such as social isolation, possible viral infections, loss of loved ones, and home-schooling children (37). In addition to these phenomena, lockdowns can create social isolation and that people usually feel lonely after severe social isolation, and it is obviously that both loneliness and social isolation negatively affect mental health (38). Furthermore, we found that younger individuals in our sample were more likely to feel depressed and anxious than older ones, with emerging adults (aged 18–29) being the group most sensitive to the mental health impact of the COVID-19 pandemic. Emerging adulthood is a developmental period characterized not only by positive role transitions into full autonomy (e.g., living independently, entering the labor market, getting married), but also by high-risk behaviors such as heavy episodic drinking (39).

Secondly, our study also shows that economic support from the government alleviates the symptoms of depression and anxiety associated with the lockdowns. Another important source of stress is economic hardship (40), and economic support as a positive intervention can mitigate the impact of negative events on individuals. Lockdown brings social isolation and anxiety, where any unexpected event such as illness or accident becomes a psychological threat and burden to individuals, while a wealthy economic base will greatly increase the individuals' ability to resist physical and psychological risk. In addition, the economic downturn caused by the COVID-19 pandemic leads to a period of economic instability during which people face unemployment and low income and develop negative perceptions about their future lives, which lead to anxiety and depression. It has been shown that a reduction in income is the greatest predictor of the development of psychological disorders during the recovery period after the SARS outbreak (41). Therefore, high-quality economic support from the government during the pandemic may enable individuals to escape from their psychological conflict-induced anxiety state, to better adapt to their environment and cope with stress, and to increase resilience.

This study makes several important contributions to the relationship between government lockdown policies and mental health during the COVID-19 pandemic. First, our study uses the data from the Household Pulse Survey and OxCGRT, takes the mental health values of all 50 states in the United States as the research samples, to examine the actual impact of government lockdown policies on mental health at the macro level, whereas most of the existing research on the relationship between lockdowns and mental health has been conducted at the individual level using first-hand survey data (7, 42, 43). Second, we found that most of the literature related to the pandemic lockdown to date has been dominated by short-term studies (8, 44), with a statistical time span of about 1 month, which does not allow for long-term tracking of the impact of lockdown policies implemented after the pandemic on mental health. Since our study covered nearly 2 years after the pandemic, we examined the impact of the government lockdown from 23 April 2020 to 30 August 2021, which better conveys the true effects of the lockdown than previous studies.

Furthermore, by exploring the relationship between the lockdown and mental health during the COVID-19 pandemic and the moderating effect of economic support, we aimed to provide a theoretical lens for ameliorating the negative impact of the lockdown on mental health and to provide practical strategies for improving the mental health of the population during the lockdown. On the one hand, from the government perspective, the implementation of lockdowns is necessary to deteriorate the spread of the pandemic (45). Although it can be effective in reducing the speed and extent of the pandemic, our study shows that it can be a significant threat to individuals' mental health. We have also demonstrated that government economic support can alleviate anxiety and depression, and we therefore suggest that the government should provide appropriate policy care for the isolated, such as income and debt support, unemployment subsidies for residents, and accelerate the establishment and improvement of an economic support system for the isolated to give them the courage to face the pandemic. Only with these measures can they face their study, work and life during the pandemic. On the other hand, from the individual's point of view, the quarantined can gain moral support and material care by confiding in or seeking help from colleagues, relatives and friends, thus enhancing their confidence in facing the tremendous pressure brought by the pandemic and relieving negative emotions and psychological stress.

There are several additional limitations to this study that need to be addressed. The first limitation relates to our measurement of regional mental health in the lockdown situation. We used only two measures of mental health, anxiety, and depression, in this study. Although these two measures are probably the most important indicators of mental health, subsequent studies will need to design and use tailored measures for psychosocial characteristics of different populations, such as loneliness and sleeping quality. In addition, due to the limitations of the dataset we used, we were unable to control for individual-level characteristics, which may have led to some bias in our results. Further research is expected to measure and compare in depth the effects of variables such as age, gender, education, work, and health conditions on mental health, providing more detailed and accurate information.

The original contributions presented in the study are included in the article/Supplementary Material, further inquiries can be directed to the corresponding authors.

All authors listed have made a substantial, direct, and intellectual contribution to the work and approved it for publication.

This work was supported by the National Social Science Fund Youth Project of China (Grant No. 17CJY019).

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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