Like people in Europe and the US, Japanese citizens were asked to stay home, wear masks, and wash their hands as part of the effort to control the spread of COVID-19. However, they were not penalised if they did not obey, even under the state of emergency. Curiously, on 7 June 2020, Japan’s death toll was only 914, whereas the death toll had reached 100,982 in the US, 40,466 in the UK, and 33,846 in Italy.1 Naturally, certain questions arise: Why were there far fewer victims of COVID-19 in Japan compared to other developed nations? Were the Japanese government’s moderate measures for curbing COVID-19 more effective overall? 

Drastic steps with penalties (such as lockdowns) have slowed the spread of the disease (Fang et al. 2020, Tian et al. 2020). On the other hand, the cost of such measures is very large, not only for the market, but also in terms of family life. Domestic violence has risen sharply due to people staying indoors under enforced lockdowns (WHO 2020). It is plausible that citizens’ mental health has deteriorated, resulting in domestic violence on the part of husbands towards their wives and from mothers towards their children. Here, another question arises: Did Japanese citizens’ mental health suffer under a moderate state of emergency?

It is important to consider the policy options to cope with COVID-19 by comparing the economic and psychological benefits (Layard et al 2020). Researchers have analysed how COVID-19 influences psychological conditions (Fetzer et al 2020, Li et al. 2020). However, studies have not examined the effect of modest actions on preventive behaviours and psychological health in Japan. As a result, we chose to fill this gap in the knowledge with our recent study.

Through an internet survey, we collected data on citizens’ preventive behaviours regarding COVID-19, and their mental health before and after the state of emergency was declared in Japan. Using the data, we scrutinised how Japanese citizens behaved and felt in response to the emergent situation of the pandemic. 

We conducted the first and second waves on 13 March and 27 March 2020, before 07 April 2020. It was on that date that the Japanese government declared a state of emergency for seven prefectures that had suffered heavily from COVID-19, including Tokyo and Osaka.2 The government requested that people avoid leaving their homes unnecessarily, and that various public places (such as schools, museums, theatres, and bars) were to be closed. Immediately after the declaration (on 10 April 2020), we carried out the third wave of the survey. We sought out the same respondents to construct short-period panel data.

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The context in Japan was novel in the sense that the state of emergency was not declared in Hokkaido and Aichi, even though the number of infected persons in these prefectures was almost equivalent to that of the other seven prefectures. Therefore, we defined the treatment group as the seven prefectures that were the target of the declaration, while we deemed the control group as comprising the Hokkaido and Aichi prefectures. 

The observations for the treatment and control groups included 5,492 and 1,269 individuals, respectively. The survey contained basic questions about demographic traits such as age, gender, educational background, household income, job status, marital status, and number of children. We considered these characteristics to be constant in the data because we carried out the three waves of the survey within a month. In addition, we asked the respondents questions on four preventive behaviours: ‘staying home’, ‘not going to work’, ‘washing one’s hands’, and ‘wearing a mask’.3 For this column, we used the mean values of the four variables as a proxy for ‘preventive behaviour’ to capture diverse facets of preventive conduct. The larger the proxy for ‘preventive behaviour’, the more citizens were likely to engage in it. With regards to mental health, we also asked the respondents about the degree of ‘anger’, ‘anxiety’, and ‘fear’ they had experienced.4 Similar to the proxy for ‘preventive behaviour’, we employed the mean values of the three variables as a proxy for ‘emotional conditions’ to capture myriad facets of emotion. We examined changes in psychological costs, such as the deterioration of mental health. The larger the values of emotional conditions, the more citizens were likely to experience the feelings mentioned above.

Figure 1 Changes in preventive behaviours

Note: The solid line indicates the treatment group, while the dashed line shows the control group.

Figure 2 Changes in mental health

Note: The solid line denotes the treatment group, while the dashed line signals the control group.

Figures 1 and 2 demonstrate the degree of changes in the ‘preventive behaviour’ and ‘emotional conditions’ of respondents between point one (the first wave on 13 March 2020) and point three (the third wave on 10 April 2020) by comparing the treatment and control groups. In Figures 1 and 2, we confirmed that the trends regarding ‘preventive behaviour’ and ‘emotional conditions’ were almost the same in the control and treatment groups, between point one and point two (the second wave on 27 March 2020), before the state of emergency was declared. Hence, there was no difference in the changes between the two groups.  

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It was important to check whether the trend before the state of emergency was declared was the same between the groups (Angrist and Pischke 2009). Between point one and two, for both ‘preventive behaviour’ and ‘emotional conditions’, the levels of variables in the treatment group were lower than those in the control group. Later, between point two and three, the slopes of the treatment group became steeper than those of the control group, and the mean values of the treatment group were comparatively higher. This made it clear that the declaration of the state of emergency led citizens to take preventive actions, even without suffering any penalty. However, the declaration also caused citizens to be experience heightened emotions. In our recent work (on which this column is based), we scrutinised the effect of the declaration more closely. We found that stress (under the state of emergency) increased ‘anger’, and that the increase in ‘anger’ was greater for husbands than for wives.

It is critical to evaluate government policies by considering their costs and benefits. Based on our findings, we argue that the declaration of the state of emergency promoted preventive behaviours while also elevating emotions. 

An increase in anger from staying indoors is thought to cause domestic violence. Family life is endangered even in Japan, where more modest measures were adopted and there have been fewer victims of COVID-19. In this regard, Japanese society shares the problem of other nations in dealing with mental health under the circumstances of the pandemic. Further, improvement of mental health plays a vital role in enhancing labour productivity and recovering from economic losses. This point should be shared throughout the world to handle the manifold difficulties of COVID-19.


Angrist, J and J-S D Pischke (2009), Mostly Harmless Econometrics: An Empiricist’s Companion, Princeton University Press.

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Fang, H, L Wang and Y Yang (2020), “Human Mobility Restrictions and the Spread of the Novel Coronavirus (2019-nCoV) in China”, NBER Working Paper 26906.

Fetzer, T, M Witte, L Hensel, J M Jachimowicz, J Haushofer, A Ivchenko, S Caria, E Reutskaja, C Roth, S Friorin, M Gomez, G Kraft-Todd, F M Goetz and E Yoeli (2020), “Global Behaviors and Perceptions in the COVID-19 Pandemic”, PsyArXiv, 16 April.

Layard, R, A Clark, J-E De Neve, C Krekel, D Fancourt, N Hey and G O’Donnell (2020), “When to Release the Lockdown? A Wellbeing Framework for Analysing Costs and Benefits”, IZA Discussion Paper 13186.

Li, S, Y Wang, J Xue, N Zhao and Z Tingshao (2020), “The Impact of COVID-19 Epidemic Declaration on Psychological Consequences: A Study on Active Weibo Users”, International Journal of Environmental Research and Public Health 17(6): 2032.

Tian, H, Y Liu, Y Li, C-H Wu, B Chen, M U G Kraemer, B Li, J Cai, B Xu, Q Yang, B Wang, P Yang, Y Cui, Y Song, P Zheng, Q Wang, O N Bjornstad, R Yang, B T Grenfell, O G Pybus and C Dye (2020), “An Investigation of Transmission Control Measures During the First 50 Days of the COVID-19 Epidemic in China”, Science 368(6491): 638-642.

World Health Organization (2020), “COVID-19 and Violence Against Women. What the Health Sector/System Can Do”. 


1 Data from Johns Hopkins University (, accessed on 8 June 2020). Compared to Western countries, there have been fewer victims in Asian countries. For example, the death toll in South Korea reached 273. However, South Korea took far more drastic steps than Japan.

2 Besides Tokyo and Osaka, we included the following prefectures in the survey: Kanagawa, Chiba, Saitama, Hyogo and Fukuoka.

3 ‘Within a week, to what degree have you performed the following behaviours’? Please answer on a scale from 1 (I have not performed this behavior at all) to 5 (I have completely performed this behaviour): (1) Staying indoors; (2) Not going to work (or school); (3) Wearing a mask; (4) Washing one’s hands carefully. The answers to these questions were proxies for preventive behaviours: staying indoors, not going to work, wearing a mask and washing one’s hands.    

4 ‘To what degree have you felt anger, fear, and anxiety’? Please answer on a scale from 1 (I have not felt this emotion at all) to 5 (I have felt this emotion strongly): (1) Anger; (2) Fear; (3) Anxiety. The answers to these questions were proxies for mental health regarding anger, anxiety and fear.