Increased Symptoms of Posttraumatic Stress in School Students Soon After the Start of the COVID-19 Outbreak in China

Hanmei Xu West China Hospital of Sichuan University Hang Zhang West China Hospital of Sichuan University Lijuan Huang West China Hospital of Medicine: Sichuan University West China Hospital Xiaolan Wang West China Hospital of Medicine: Sichuan University West China Hospital Xiaowei Tang West China Hospital of Medicine: Sichuan University West China Hospital Yanping Wang West China Hospital of Sichuan University Qingqing Xiao West China Hospital of Medicine: Sichuan University West China Hospital Ping Xiong Chengdu Emgineering,Vocational and Technical School Rongqiu Jiang Chengdu Engineering,Vocational and Technical school Jie Zhan Xuchuan Middle School Fang Deng West China Hospital of Medicine: Sichuan University West China Hospital Mingya Yu Jiangsu Academy of Social Sciences Dong Liu Wenquan Second Central Primary School Xuejun Liu Jiangsu Shuangdian Primary School Chunli Zhang The Sixth Middle School of Jianshui County Wenjun Wang Egongyan Primary School Lu Li The 12th Elementary School of Nanyang City Hongmei Cao Hou Central School Wenchao Zhang Chongqing Yinxiang West Normal School and A liated Primary School Hongping Zhou Chengdu Shuangliu Yongan Middle School Wo Wang University-Town Hospital of Chongqing Medical University Li Yin (  yli009@163.com ) Mental Health Center, West China Hospital of Sichuan University, No. 28 Dianxin South Street, Chengdu, Sichuan 610041, China Frontiers Science Center for Disease-related Molecular Network, Chengdu, Sichuan 610041, China https://orcid.org/0000-0002-7448-0284


Background
Studies have shown an increased incidence of post-traumatic stress in survivors of large-scale disasters [1][2][3][4]. Disasters can be de ned as destructive occurrences that disrupt and overwhelm entire communities and affect millions worldwide in a given year [5].Children who have experienced disasters are more vulnerable than adults to mental and psychological disorders, including post-traumatic stress disorder (PTSD) [6][7][8]. Disasters can severely affect their emotional status, resulting in stress reactions that are different from those experienced by adults [9,10].In addition, children may develop serious psychological and mental illnesses that occur sooner and last longer than those in adults [11][12][13].
In the 21st century, a number of infectious diseases have challenged global public health [14]. During the epidemic of severe acute respiratory syndrome in February 2003, many adult patients developed post-traumatic stress symptoms, PTSD, anxiety, depression, and other mental illnesses [15][16][17][18].The current COVID-19 pandemic, caused by novel coronavirus SARS-CoV-2, constitutes a global public health disaster [19].We are unaware of studies of whether and how the pandemic causes psychological stress on children.
Therefore, we investigated the prevalence of post-traumatic stress symptoms in primary and secondary school students from several provinces and regions in China at one month after the start of the COVID-19 outbreak. Our results may help elucidate the effects of the pandemic on the psychological health of children.

Subjects
Participants included students from several primary and secondary schools in Sichuan, Jiangsu, Henan, Yunnan, and Chongqing. We included a range of students, from those attending rst grade of primary school (8 years) to those in the third grade of senior high school (18 years). Participants were strati ed into primary school students (grades1-6), junior high school students (grades7-9), and senior high school students (grades10-12).We excluded students with a history of substance abuse, those suffering from major physical and mental illnesses, including Axis I and Axis II disorders classi ed by the Diagnostic and Statistical Manual of Mental Disorders IV (DSM-IV) based on self-report; as well as those who could not understand the questionnaire.
The minimal sample size required for this study was calculated based on the typical sample size for questionnaire-based surveys of the occurrence of posttraumatic stress after disasters. Based on a PTSD prevalence of 32.2% in China after the outbreak of COVID-19 [19], we calculated a minimal sample of 2097 for a power of 0.8, type I error of 0.05 and allowable error of 0.02. We increased this by 10% to 2330 to compensate for missing or uncooperative participants.

Measurement
Between 1 February 20 and 1 March 1 2020, approximately one month after the outbreak of the novel coronavirus infection in China, we collected demographic and psychopathological data from the participants using the Chinese versions of the General Situation Collection Sheet revised in 2010 and the Children's Revised Impact of Event Scale (CRIES) questionnaire [20]. The two questionnaires were distributed via WeChat, and their purpose and contents were explained to all participants. Questionnaires couldn't be submitted until they completed all questions.
The CRIES-13 measures symptoms of intrusion (4 items), avoidance (4 items), and arousal (5 new items). Answer item is set as "not at all", "rarely", "sometimes", and "often" [20,21]. The CRIES-13 total score is used to judge the severity of the psychological impact caused by a traumatic event. A total score ≥ 30 is considered to indicate severe psychological stress [21][22][23].

Statistical analysis
All statistical analyses were performed using SPSS 25.0(IBM, Armonk, NY, USA), and the signi cance level was set as α = 0.05.We analyzed participant data and compared CRIES-13 scores across groups using the Chi-squared, Mann-Whitney U, and Kruskal-Wallis H tests. Post-hoc comparisons were conducted after adjusting the level of signi cance using Bonferroni correction. considered the in uence of sex, age, grade, family structure, occupation of parents, past history of psychological illness (history of psychological consultations or use of psychotropic drug therapy), recent diagnosis of coronary disease, and exposure to coronavirus infection within the previous 30 days.
Questions about infection exposure addressed the number of visits to Hubei province and surrounding areas, contact with patients diagnosed with COVID-19, incidence/occurrence of cold, fever, cough, nasal congestion, runny nose, sore throat, and diarrhea, and participation in large gatherings, such as dinner parties. Exposure was also assessed based on contact with family members who were doctors and frontline workers, as well as relatives within three generations who had been diagnosed with COVID-19 or were suspected of having coronary disease. We also included data on whether participants had received therapy against COVID-19, or had fever and other mild symptoms.

Demographic and clinical characteristics of subjects
Our survey included a total of 7769 students (4077 female) from 5 different provinces in China (Table 1). All participants were between 8 and 18 years old (median 15 years), and were strati ed into three groups based on their grade: primary school students (15.62%, median age 11 years), junior high school students (36.03%, median age 13 years), and senior high school students (48.35%, median age 16 years). In total, 24 participants (13 males and 11 females) were diagnosed with COVID-19, and 27 (16 males and 11 females) were suspected of being infected with the disease. students had family members who had been diagnosed with COVID-19.Participants were also exposed to the virus via family members who were doctors (272 students) and frontline workers (111 students).
The stress response of participants to the COVID-19 pandemic was measured based on CRIES-13 total score. A total of 1639 (21.1%) students experienced severe symptoms of psychological stress (total score ≥ 30; Table 2).These symptoms were more serious in senior high school students (23.3%) compared to primary students (20.3%) and junior high school students (18.4%) (χ 2 = 23.5, p < 0.001). A higher proportion of female students suffered severe psychological stress than male students (22.3% vs 19.7%; χ 2 = 8.03, p = 0.005). To understand the degree of impact of COVID-19, we compared total CRIES-13 scores among primary school, junior high school, and senior high school student susing the Kruskal-Wallis H test. We found a signi cant difference among the three groups (H = 75.512, p < 0.001; Table 2); median total CRIES-13 score was the highest for senior high school students (21), followed by the junior high school (19) and primary students (18).
After adjusting the level of signi cance using Bonferroni correction, a post-hoc comparison found that total CRIES-13 scores were signi cantly lower for primary school students (Z =-7.469, adjusted p < 0.001) and junior high school students(Z = -6.616, adjusted p < 0.001) than for senior high school students. However, total scores were not signi cantly different between primary school and junior high school students (Z=-2.368, adjusted p = 0.054; Table 3). Across all three student groups, female students had higher total scores than males (median 21 vs 19; Z=-5.739, p < 0.001; Table 2). We observed signi cant differences among the three groups of students in intrusion (H = 103.14, p < 0.001), arousal (H = 183.669, p < 0.001), and avoidance factor scores (H = 45.492, p < 0.001) ( Table 2). Post-hoc comparisons of the intrusion factor showed that junior high school students had higher scores than primary students (Z=-7.933, adjusted p < 0.001), while senior high school students had higher scores than primary students (Z=-10.120, adjusted p < 0.001) and junior high school students (Z=-2.463, adjusted p = 0.041; Table 3).
Pairwise comparison of the arousal factor showed that junior high school students had higher scores than primary students (Z=-5.200, adjusted p < 0.001), and senior high school students had higher scores than primary students (Z=-12.382, adjusted p < 0.001) and junior high school students (Z=-9.214, adjusted p < 0.001). In contrast, primary school students had higher avoidance factor scores than junior high school students (Z = 6.7, adjusted p < 0.001) and senior high school students (Z = 4.327, adjusted p < 0.001), and the scores of junior high school students were lower than those of senior high school students (Z=-3.499, adjusted p < 0.001; Table 3).
We performed logistic regression to determine the factors affecting total CRIES-13 scores and stress responses. Our results showed that stress response was in uenced by the sex of the participant(p = 0.024), school grade (p = 0.001), past history of psychological counseling (p < 0.001), exposure to infection via relatives (p = 0.009), and a recent diagnosis of COVID-19 (p = 0.006; Table 4).Individuals suffering from cold, fever, cough, nasal congestion, runny nose, sore throat, and diarrhea within 30 days of taking part in the survey also had a heightened stress response (p = 0.002).

Discussion
In this study, we examined the early effects of the COVID-19 pandemic on the mental and psychological health of 7769 school students in China using the CRIES-13. Based on total CRIES-13 scores, 1639students (21.1%) experienced symptoms of severe psychological stress, indicating an urgent need to understand the impact of such events on the mental health of children and adolescents.
Women are more likely to experience acute stress reactions and to be at higher risk of PTSD than men [24][25][26][27][28][29][30].In addition, women often show higher scores than men on the invasion and avoidance factors of the CRIES-13 [31,32]. These sex differences are associated with age, suggesting that older individuals respond differently to stressful events than younger ones [31][32][33][34][35][36][37]. Consistent with these results, we found that the largest proportion of students experiencing severe psychological stress were in senior high school. Similarly, studies of children exposed to war violence found older children to be more vulnerable to stress [38]. However, a survey of 8236 US children in grades 4-12 at 6 months after the 9/11 attacks found that primary school students (grades 4-5) were at higher risk of post-traumatic stress symptoms than junior and senior high school students [39]. This discrepancy may re ect that different grades of students may have different degrees of stress disorder under the in uence of different events. Future research should focus on more different events.
We found that senior high school students had higher scores on arousal and invasion factors on the CRIES-13, but primary school students had higher avoidance factor scores. This suggests that senior high school students are more likely to feel frightened or anxious, experience ashback reactions associated with the event, and manifest symptoms of arousal. The immaturity of the cognitive process in younger children can make them less susceptible to recurring intrusive thoughts and other cognitive impacts of trauma [40,41]. A maladaptive cognitive style in adolescents and older children may compromise their ability to regulate emotions, rendering them more vulnerable to PTSD [42].
Based on the regression analysis, we found that the occurrence of cold-related symptoms within one month of participating in the survey signi cantly in uenced stress response. Based on studies of the spread of various viruses, psychosocial factors are related to experimental exposure and infection rates. Creactive protein (CRP) is an acute-phase reactant downstream of the pro-in ammatory cytokines released during in uenza infection [43].Studies have shown that a marker of peripheral in ammation, plasma CRP, may be prospectively associated with PTSD symptom emergence, suggesting that in ammation may predispose to PTSD [44].On the other hand, the increasing number of patients and suspected cases, and the increasing number of outbreak affected provinces and countries have elicited public worry about becoming infected [45]. As we know, the most common symptoms associated with COVID-19 are fever, cough, dyspnea, expectoration, headache, and myalgia or fatigue [46]. This is similar to the symptoms of the common cold [47].Particularly, the relevance of perceived threat for health and life and the experienced feelings of vulnerability as mediating factors [48].It was repored that mental health symptoms may have been common during the COVID-19 outbreak among the general population in China, especially among infected individuals, people with suspected infection, and people who might have contact with patients with COVID-19 [49].This is consistent with our research results.
Although previous studies have explored the impact of the SARS epidemic on mental health, this is the rst study addressing the psychological impact of COVID-19 on children and adolescents. Using a relatively large sample ranging widely in age, we were able to conduct a cross-sectional study of the mental and emotional status of students at one month after the outbreak began in China. There were no participants from Hubei province, which were subsequently identi ed as being caused by a novel coronavirus termed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) [19].However, this may have caused a bias since the participants were selected from schools in certain regions in China, resulting in ndings that may not be generalizable across all children and adolescents. In addition, the survey involved substantially more high school students than primary school students. Even though the timing of the survey may help identify participants who require psychological and clinical intervention, the cross-sectional design meant that we could not assess how persistent the post-traumatic stress symptoms are.

Conclusions
In conclusion, our results showed that COVID-19 has placed psychological stresses on primary and secondary school students in China. These stresses are more likely to reach severe levels among female students and senior high school students.

Availability of data and material
The data that support the ndings of this study are available on request from the corresponding author (Li Yin, yli009@163.com). The data are not publicly available due to privacy or ethical restrictions.

Competing interests
The authors declare that they have no competing interests. WW helped collect the data. HM X, HZ analyzed the data. HM X, HZ and LY wrote and revised the manuscript. All authors have read and approved the manuscript.