Evaluation of psychological stress in scientific researchers during the 2019–2020 COVID-19 outbreak in China

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Brain, Cognition and Mental Health

Introduction

The outbreak of coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), originated in Wuhan, China and quickly spread from human to human in December 2019 (Lai et al., 2020). On 30 January 2020, the World Health Organization declared the COVID-19 epidemic a public health emergency of international concern. As of 28 February 2020, China has confirmed 77,150 new coronavirus infections and 2,592 deaths (Pediatric Committee, Medical Association of Chinese People’s Liberation Army and Editorial Committee of Chinese Journal of Contemporary Pediatrics, 2020; Martinez, 2020). Because of the increasing number of confirmed cases and deaths, negative emotions continued to spread (Zhou, 2020). Previous studies (Hull, 2005; Wu, Chan & Ma, 2005a, 2005b) suggest we must examine the extent of psychological stress associated with the current epidemic and focus attention on those people most vulnerable to this psychological stress (Shigemura et al., 2020). Recent studies have focused on the psychological stress of the medical staff involved in epidemic prevention in China (Xiao et al., 2020). However, few studies have examined the impact of severe infectious disease outbreaks on the psychological state of researchers. The rise of stressors and strains in academic life has been widely reported (Kinman, 2001). Heavy workload and time and resource constraints have been highlighted as major work stressors in researchers. The work-home imbalance and role conflict and overload also have potential impact on academic stress level (Gmelch, Lovrich & Wilke, 1984; Kinman, 2008; Tytherleigh et al., 2005). At the same time, stress from dissatisfaction with pay and benefits has been reported (Tytherleigh et al., 2005). Management and leadership styles, a pressured higher education climate, and unhealthy competition also cause harmful stress (Wellcome, 2020).

To avoid further transmission of COVID-19, many industries were forced to shut down temporarily, and scientific and social research and education activities were paused in China (Couzin-Frankel, 2020). Furthermore, animal centers and practical labs were closed, and many scientific and social congresses and symposiums were cancelled, leaving postgraduates and scientific workers confined to their homes (Service, 2020). Therefore, many researchers’ experimental progress was hindered (e.g., due to loss of samples and funds) (Service, 2020; Tencent, 2020a, 2020b), which undoubtedly increased the psychological stress on academic and research staff. In addition, the stagnation of science education activities may cause an increase in students’ graduation pressure, and even the delay of graduation (Tencent, 2020a).

In the current research, we propose the following hypotheses: (1) the COVID-19 outbreak aggravated psychological stress in researchers; (2) the stress levels and stressors in diverse populations would be different; (3) the demands for reducing stress in diverse populations would be different. We included 42 related questions in a questionnaire to test the above hypotheses. Respondents were categorized by research field, research degree and affiliation, etc.

Materials and Methods

Study participants

A questionnaire was distributed to researchers in China to recruit an opportunity sample, and all respondents were asked to answer each question on their own. The targets of the questionnaire were identified as “scientific researchers”, which requires the respondents to be involved in at least one research project in past 12 months. Questionnaires were distributed to research institution staff, university researchers and students participating in the research. They were all researchers with a confirmed scientific experience or people the authors had collaborated with before. Some respondents passed on the questionnaire to other qualified people to fill in. A total of 251 questionnaires was received after screening. As the investigators are scientific researchers, they have a high level of education and are familiar with the questions. In addition, the respondents’ answers were internally consistent. In particular, the 193 respondents who chose ‘At a standstill’ or ‘still in progress but slower than before’ due to the epidemic situation (question 37) responded with psychological states (questions 38–39) that matched this answer. All participants provided written informed consent, and subjects were anonymous. It is not required by our institution to obtain ethical approval for a survey with a nonclinical sample and anonymised data, but we did obtain retrospective approval for the study protocol from the institutional review board (Ethics Committee) of the 3rd Xiangya Hospital, Central South University (20005-IRB).

Questionnaire

We included 42 related questions in the questionnaire to acquire a comprehensive understanding of the progress of research projects and the current psychological stress level of researchers. The survey consisted of 24 questions assessing the subject’s psychological stress (i.e., stress scale). The questionnaire incorporated modified questions from the stress response questionnaire (SRQ) and the Pittsburgh sleep quality index scale (PSQI) (Pilz et al., 2018) and considered the current COVID-19 epidemic (i.e., emotional state, somatic responses, sleep quality and behavior). The stress scale consisted of five self-evaluation options: (1) not at all, (2) occasionally, (3) sometimes, (4) often and (5) always. A score of 5 represented the highest level of stress.

We also assessed participants’ research areas (e.g., whether they conduct research related to the novel coronavirus) and potential stagnation of research projects, including questions rated to (1) delay in scientific research projects, (2) sample or funding losses due to the current epidemic and (3) disruption of academic exchange activities. At the conclusion of the questionnaire, subjects were invited to evaluate some recommendations and proposed solutions for potential changes to scientific research in China, including extending deadlines for project completion, providing partial financial subsidies for scientific research losses, assigning professional personnel to guide and support scientific research projects, and prioritizing the return of researchers to work (see Supplement 1).

Statistical analysis

Questionnaire results were summarized from the imported Excel file and analyzed using SPSS version 18.0 software (IBM Corp., Armonk, NY, USA). Quantitative variables were expressed as an average with a standard deviation (SD). Qualitative variables were expressed as numbers and percentages. Chi-squared (χ2) tests and analysis of variance (ANOVA) tests were used to compare psychological factors across social roles and age groups. A p value less than or equal to 0.05 was considered statistically significant.

Results

Participant demographics

Participants included scholars in the fields of life science (e.g., medicine, biology), engineering science (e.g., mechanical engineering, physiology, chemistry) and humanities and social sciences (e.g., law, literature). The gender ratio of the respondents was approximately 1:1. The average age of participants was 28.91 ± 8.65, most of whom were from colleges or university affiliated hospitals (Table 1). Participants consisted of seven groups of people: undergraduate students, Master’s degree candidates (non-graduation year), Master’s degree candidates (graduation year), PhD candidates (non-graduation year), PhD candidates (graduation year), basic research staff (including postdoctoral), and clinical medical staff (including postdoctoral). Many participants were undergraduates and clinical medical staff without advanced degrees, who comprise the majority of researchers in China and are therefore the most vulnerable to research-related psychological stress from infectious disease outbreaks.

Table 1:
Demographic characteristics of respondents.
Demographic characteristics N %
Gender Male 104 41.43
Female 147 58.57
Age 18–24 109 43.43
25–39 119 47.41
40–59 22 8.76
≥60 1 0.4
Category of school or institution Top universities 177 70.52
General college 13 5.18
Independent research institutes (including research institutes) 4 1.59
University affiliated hospital 55 21.91
Non-university affiliated hospital 2 0.8
Education background Undergraduates 79 31.47
Master candidate (non-graduate) 28 11.16
Master candidate (graduation grade) 9 3.59
PhD candidate (non-graduate year) 23 9.16
PhD candidate (graduation year) 20 7.97
Basic research staff (including postdoctoral) 31 12.35
Clinical medical staff (including postdoctoral) 61 24.3
Title of technical post Professor (researcher, chief physician) 11 4.38
Associate professor (associate researcher, associate chief physician) 22 8.76
Lecturer (assistant researcher, attending physician) 44 17.53
None 174 69.32
Total 251 100
DOI: 10.7717/peerj.9497/table-1

Impact of epidemic-related scientific delays on stress levels

Of the 251 researchers surveyed, the average score of the population’s stress level was 46.99 ± 20.84 points (full mark: 120 points). The median score was 43 points, the lowest score 24 points, and the highest score 120 points (Table 2). Participants whose progress was affected by the outbreak had higher levels of stress than participants who were not affected by the outbreak. Participants who indicated that they were affected by the epidemic expressed higher stress in emotional states, somatic responses, and behavior than participants who indicated they were not affected by the epidemic (Table 3).

Table 2:
Scores and statistical analysis of researchers’ stress levels.
Question number Dimensions n = 251
Min Max Means ± SDs Median
13–20 Emotional state 8 40 15.85 ± 7.93 14
21–25 Somatic responses 5 25 10.18 ± 5.05 9
26–29 Sleep quality 4 20 8.24 ± 4.08 7
30–36 Behavior 7 35 12.73 ± 5.50 11
Total scores 24 120 46.99 ± 20.84 43
DOI: 10.7717/peerj.9497/table-2

Note:

“±” Represents standard deviation.

Table 3:
Impact of the delay of project on researchers’ stress levels.
Question number Dimensions Completion date of scientific research project was delayed by coronavirus F p
Disagree (n = 83) Agree (n = 168)
13–20 Emotional state 13.72 ± 6.24 16.90 ± 8.47 9.194 0.003**
21–25 Somatic responses 9.16 ± 4.21 10.68 ± 5.35 5.181 0.024*
26–29 Sleep quality 7.59 ± 3.47 8.55 ± 4.32 3.131 0.078
30–36 Behavior 11.35 ± 4.42 13.41 ± 5.86 8.021 0.005**
DOI: 10.7717/peerj.9497/table-3

Notes:

p < 0.05.
p < 0.01.

“±” Represents standard deviation.

We identified 14 possible predictors of high stress in researchers during the COVID-19 outbreak and conducted the variables with means and SDs on stress levels. As a result of the outbreak, researchers who were required to change or reduce experimental projects indicated they were under more pressure than those who did not have to change or reduce their experimental project. In addition, researchers were affected by peer pressure because their colleagues had been reporting on new coronavirus-related research (Table 4). We did not report a separate analysis of correlation between research stress and influencing factors in different research disciplines, due to the limited sample size. The impact of “Original research programs need to be changed or cut” on stress levels and the impact of “Feeling great pressure on colleagues who conduct projects on COVID-19” on stress levels are additionally listed in Tables 5 and 6.

Table 4:
All the variables with means and SDs on stress levels.
Variable Answers Numbers Means ± SDs t p
Delayed completion date of research project. Disagree 83 41.82 ± 16.41 −3.102 0.002**
Agree 168 49.55 ± 22.32
The blocked research projects caused by the COVID-19 has influenced the graduation/project conclusion/funds applications Disagree 122 42.93 ± 17.68 −3.071 0.002**
Agree 129 50.83 ± 22.85
Original research programs need to be changed or cut Disagree 168 43.20 ± 16.65 −3.681 0.000**
Agree 83 54.67 ± 25.89
The epidemic reduced the timeliness of the experimental results. Disagree 157 44.33 ± 18.43 −2.484 0.014*
Agree 94 51.44 ± 23.79
The epidemic has caused the loss of experimental materials and samples. Disagree 169 44.27 ± 17.47 −2.652 0.009**
Agree 82 52.60 ± 25.69
The COVID-19 asked more energy input Disagree 91 43.37 ± 17.19 −2.245 0.026*
Agree 160 49.05 ± 22.45
The COVID-19 has already, or is about to, caused a great loss for projects Disagree 160 44.63 ± 18.68 −2.252 0.026*
Agree 91 51.14 ± 23.72
The COVID-19 has influenced the original academic exchange activities Disagree 82 44.96 ± 18.50 −1.075 0.284
Agree 169 47.98 ± 21.87
The COVID-19 has Influenced the cooperation with other organizations Disagree 123 45.14 ± 19.30 −1.384 0.168
Agree 128 48.77 ± 22.15
Colleagues have carried out research projects on COVID-19. Disagree 150 45.34 ± 19.11 −1.535 0.126
Agree 101 49.45 ± 23.05
I am doing/have done a research project on COVID-19. Disagree 197 46.16 ± 19.42 −1.038 0.303
Agree 54 50.02 ± 25.32
Feeling great pressure from colleagues who conduct projects on COVID-19 Disagree 184 44.06 ± 17.55 −3.153 0.002**
Agree 67 55.04 ±2 6.48
The block of the scientific researched has caused the adverse effects on your career Disagree 151 44.11 ± 17.80 −2.570 0.011*
Agree 100 51.35 ± 24.18
The block of the scientific researched has caused the adverse effects on your salaries Disagree 168 45.15 ± 19.30 −1.881 0.062
Agree 83 50.72 ± 23.34
Total 251
DOI: 10.7717/peerj.9497/table-4

Notes:

p < 0.05.
p < 0.01.
Table 5:
The impact of “Original research programs need to be changed or cut” on stress levels.
Question number Dimensions Original research programs need to be changed or cut F p
Disagree (n = 168) Agree (n = 83)
13–20 Emotional state 14.25 ± 6.31 19.08 ± 9.74 22.391 0.000**
21–25 Somatic responses 9.32 ± 4.14 11.93 ± 6.16 15.775 0.000**
26–29 Sleep quality 7.80 ± 3.51 9.12 ± 4.94 5.971 0.015*
30–36 Behavior 11.83 ± 4.62 14.54 ± 6.61 14.184 0.000**
Total scores 43.20 ± 16.65 54.67 ± 25.89 18.001 0.000**
DOI: 10.7717/peerj.9497/table-5

Notes:

p < 0.05.
p < 0.01.
Table 6:
The impact of “Feeling great pressure from colleagues who conduct projects on COVID-19” on stress levels.
Question number Dimensions Feeling great pressure on colleagues who conduct projects on COVID-19 F p
Disagree (n = 168) Agree (n = 83)
13–20 Emotional state 14.80 ± 6.82 18.73 ± 9.89 12.628 0.000**
21–25 Somatic responses 9.57 ± 4.32 11.87 ± 6.38 10.605 0.001**
26–29 Sleep quality 7.78 ± 3.48 9.49 ± 5.21 8.982 0.003**
30–36 Behavior 11.92 ± 4.74 14.96 ± 6.75 15.861 0.000**
Total scores 44.06 ± 17.55 55.04 ± 26.48 14.378 0.000**
DOI: 10.7717/peerj.9497/table-6

Notes:

p < 0.05.
p < 0.01.

Responses regarding recommendations to improve conditions for scientific researchers

Nine proposed solutions were considered by researchers to possibly ease their stress (Fig 1). The top recommendation was prolonging the graduation/project conclusion/the deadline of the application of the funds, with 161 of 251 (64.14%) respondents regarding it effective. Receiving support from superiors (51.79%) and improving the welfare of researchers (51.00%) came next. Academic cooperation (27.49%) and meetings (21.91%) received lower levels of endorsement. These demands varied statistically between clinical staff and basic medical researchers, as well as between master’s and doctoral students (Tables 7 and 8).

Some recommendations that researchers considered effective to relieve pressure from the coronavirus pandemic (251 participants).

Figure 1: Some recommendations that researchers considered effective to relieve pressure from the coronavirus pandemic (251 participants).

Table 7:
A comparison of recommendations endorsed by basic medical researchers and clinical medical staff.
Appeals Education background Total χ2 p
Basic research staff (including postdoctoral) Clinical medical staff (including postdoctoral)
Prolonging the graduation/project conclusion/the deadline of the application of the funds Disagree 12 (38.71) 23 (37.70) 35 (38.04) 0.009 0.925
Agree 19 (61.29) 38 (62.30) 57 (61.96)
Providing funds for the loss of the researches Disagree 14 (45.16) 33 (54.10) 47 (51.09) 0.657 0.418
Agree 17 (54.84) 28 (45.90) 45 (48.91)
Improving the welfare of the researchers Disagree 11 (35.48) 30 (49.18) 41 (44.57) 1.561 0.212
Agree 20 (64.52) 31 (50.82) 51 (55.43)
Providing free consulting and psychotherapies Disagree 21 (67.74) 43 (70.49) 64 (69.57) 0.073 0.786
Agree 10 (32.26) 18 (29.51) 28 (30.43)
Assigning professionals to guide projects Disagree 25 (80.65) 32 (52.46) 57 (61.96) 6.928 0.008**
Agree 6 (19.35) 29 (47.54) 35 (38.04)
Encouragement from the superiors Disagree 15 (48.39) 29 (47.54) 44 (47.83) 0.006 0.939
Agree 16 (51.61) 32 (52.46) 48 (52.17)
Prioritizing the return of researches to work Disagree 15 (48.39) 44 (72.13) 59 (64.13) 5.038 0.025*
Agree 16 (51.61) 17 (27.87) 33 (35.87)
Organizing more academic meetings Disagree 22 (70.97) 48 (78.69) 70 (76.09) 0.673 0.412
Agree 9 (29.03) 13 (21.31) 22 (23.91)
Develop more academic cooperative projects Disagree 23 (74.19) 39 (63.93) 62 (67.39) 0.984 0.321
Agree 8 (25.81) 22 (36.07) 30 (32.61)
Total 31 61 92
DOI: 10.7717/peerj.9497/table-7

Notes:

p < 0.05.
p < 0.01.
Table 8:
A comparison of recommendations endorsed by masters and PhD students.
Appeals Education background Total χ2 p
Master PhD
Prolonging the graduation or the expected finish time of the experiment Disagree 14 (37.84) 17 (39.53) 31(38.75) 0.024 0.877
Agree 23 (62.16) 26 (60.47) 49 (61.25)
Providing supports for the loss of the researches Disagree 19 (51.35) 23 (53.49) 42 (52.50) 0.036 0.849
Agree 18 (48.65) 20 (46.51) 38 (47.50)
Improving the welfare of the researchers Disagree 18 (48.65) 15 (34.88) 33 (41.25) 1.555 0.212
Agree 19 (51.35) 28 (65.12) 47 (58.75)
Providing free counselling and psychotherapies Disagree 27 (72.97) 31 (72.09) 58 (72.50) 0.008 0.93
Agree 10 (27.03) 12 (27.91) 22 (27.50)
Assigning professionals to guide projects Disagree 21 (56.76) 18 (41.86) 39 (48.75) 1.766 0.184
Agree 16 (43.24) 25 (58.14) 41 (51.25)
Supports from the superiors Disagree 14 (37.84) 20 (46.51) 34 (42.50) 0.612 0.434
Agree 23 (62.16) 23 (53.49) 46 (57.50)
Prioritizing the return of researchers to work Disagree 29 (78.38) 21 (48.84) 50 (62.50) 7.405 0.007**
Agree 8 (21.62) 22 (51.16) 30 (37.50)
Organizing more academic meetings Disagree 31 (83.78) 33 (76.74) 64 (80.00) 0.616 0.433
Agree 6 (16.22) 10 (23.26) 16 (20.00)
Develop more academic cooperative projects Disagree 30 (81.08) 33 (76.74) 63 (78.75) 0.224 0.636
Agree 7 (18.92) 10 (23.26) 17 (21.25)
DOI: 10.7717/peerj.9497/table-8

Notes:

p < 0.05.
p < 0.01.

COVID-19 affected research progress differently across research fields and seniority

As a result of the COVID-19 outbreak, 47.11% of researchers in the field of science indicated their research programs were halted, and 32.00% of researchers indicated their programs, while ongoing, were slower than before the epidemic began. However, the COVID-19 epidemic has had relatively little impact on researchers in the field of humanities, with most social science researchers indicating a slower pace of research (6 out of 12) or a lack of impact of COVID-19 on their research (5 out of 12). It is worth noting that we classify such scholars as “in the field of humanities and social sciences”, in fact, their research projects are concerning, say, “The human impact of the epidemic” and “cultural reasons for differences in national responses”. These types of researches are scientific, though they tend to focus more on humanities. Of the 77 professors and lecturers surveyed, 43 (55.84%) indicated that their experiment was at a standstill, while 8 (10.39%) indicated that their experiment was not affected. However, the responses of researchers without professional titles varied, with 43.82% of researchers indicating stagnated experiments and 23.11% indicating unaffected projects respectively (Tables 9 and 10).

Table 9:
Research progress in different fields affected by COVID-19.
Research field (%) Total χ2 p
Science Humanities
Scientific research projects you participated in during the COVID-19 outbreak are At a standstill 106 (47.11) 1 (8.33) 107 (45.15) 7.158 0.028*
Still under way but at a slower pace than before 72 (32.00) 6 (50.00) 78 (32.91)
Completely unaffected 47 (20.89) 5 (41.67) 52 (21.94)
Total 225 12 237
DOI: 10.7717/peerj.9497/table-9

Notes:

p < 0.05.
p < 0.01.
Table 10:
Research progress under the influence of COVID-19 by different title of the technical post.
Title of the technical post (%) Total χ2 p
Lecturers and Professors None
Scientific research projects you participated in during the COVID-19 outbreak are At a standstill 43 (55.84) 67 (38.51) 110 (43.82) 11.453 0.003**
Still under way but at a slower pace than before 26 (33.77) 57 (32.76) 83 (33.07)
Completely unaffected 8 (10.39) 50 (28.74) 58 (23.11)
Total 77 174 251
DOI: 10.7717/peerj.9497/table-10

Notes:

p < 0.05.
p < 0.01.

Discussion

There may be many subjective or objective factors preventing the achievement of motivating factors like job achievement, income, respect, reputation, work pride, promotion opportunities, etc. Hindered scientific research progress may lead to reduced salaries and promotion opportunities and could delay job achievement. It might also discourage many researchers who had family or other social responsibilities. The resulting stress might be internalized and cause adverse psychological consequences (Kinman, 2008; Liu et al., 2019). The results showed participants whose progress was affected by the outbreak had higher levels of stress. This is consistent with the study that work interruption is a common source of stress for researchers (Gmelch, Lovrich & Wilke, 1984). We found that researchers who reported needing to change their original research programs often faced more pressure. This indicated the change of work content in a short time may be difficult for researchers to deal with (Kinman, 2001). Participants who indicated pessimism about halted or slowed research progress also had higher levels of stress than participants who were optimistic. These data provide evidence that we should promote the importance of psychological and mental health in researchers and provide intervention guidance during times such as infectious disease outbreaks (Jiang et al., 2020). In addition, previous research has described that most researchers faced unhealthy competition and high levels of competitive pressure at work (Randall et al., 2019; Wellcome, 2020). In our study, researchers whose colleagues were conducting related research on COVID-19 showed increased stress levels. This suggested that with the full efforts of researchers to study COIVD-19, the stress of scientific research competition also intensified.

To help determine interventions to reduce researchers’ stress, we asked researchers to provide suggestions regarding how to respond to the demands. The top recommendation was extending the deadline for experimental projects. This was because the delay of experimental progress often affected original research plans, such as applying for funding and students’ graduation. The results showed that “receiving support from superiors” would also help to reduce stress. In previous studies, many respondents reported that their workplace put overwhelming expectations on them and that the superiors’ blame led to an increase in staff dissatisfaction. In contrast, “respect” and “caring for others” were considered positive leadership styles (Kobulnicky, 1997; Merrill, 2015; Morsiani, Bagnasco & Sasso, 2017; Wellcome, 2020). In addition, inadequate salary and slow career advancement have been considered as stressors for researchers (Gmelch, Lovrich & Wilke, 1984; Kinman, 2001). This explains the requirement to improve the welfare of researchers.

Importantly, with graduation deadlines approaching, many students may have felt pressure to complete their qualifications. The lack of science educational activities during the pandemic could entail delay of graduation. Furthermore, perceived stress was correlated with academic level: stress increased with a higher academic level (Fadhel & Adawi, 2020). Also, uncertainty around doctoral students and post-doctoral researchers’ careers may have made them more vulnerable to publication stress (Frandsen et al., 2019). We found that students pursuing a PhD degree showed a stronger willingness to prioritize the return of researchers to work than students pursuing a master’s degree.

Researchers in the life sciences and engineering indicated that their scientific research was more severely hindered than those in the social sciences and other fields. Most life sciences and engineering fields rely on experimental facilities to complete their research; the closure of those facilities during the epidemic created a great obstacle for completing their research (Service, 2020; Tencent, 2020a, 2020b). In contrast, researchers in social sciences and other fields could often still conduct research activities during the outbreak.

This study has several limitations. The sample size was too small to conduct the population-level sample comparisons that we had anticipated. Further, because this study took place one month after the outbreak began, psychological stress may not have occurred yet. Long-term psychological impacts of infectious disease outbreaks on scientific researchers, such as PTSD, should be investigated in future studies. Finally, we did not compare researcher stress between Hubei (the initial and severe outbreak location) and other regions because there were few respondents from Hubei.

Conclusions

Research progress was hindered by the COVID-19 outbreak, especially for researchers in the life sciences (e.g., basic medicine and clinical medicine). Researchers who were affected by the outbreak indicated higher psychological stress levels, especially emotional states, somatic responses and behaviors. Our investigation suggests that the pressure placed on researchers during an epidemic comes mainly from lack of experimental progress and competition among peers. Additionally, clinical medicine researchers were also concerned that the value of their experimental results would be reduced because of delays in progress. The majority of respondents indicated that effective ways to relieve stress included extending deadlines, receiving research support from superiors, and increasing benefits for researchers. The results of this investigation suggest that in addition to focusing on restoring normal order of the laboratory after the novel coronavirus pandemic, it is also important to improve the psychological state of researchers.

Supplemental Information

Questionnaire sample.

DOI: 10.7717/peerj.9497/supp-1

Raw data: The original answers of each questionnaire.

DOI: 10.7717/peerj.9497/supp-2
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