Community trauma exposure and post-traumatic stress disorder in Chinese children and adolescents

Background An increasing number of studies have shown the association between traumatic events occurring in childhood and adolescence and post-traumatic stress disorder (PTSD). A gap remains in the literature on the epidemiology and influencing factors of traumatic events and post-traumatic stress disorder in communities in northern China. This study aimed to determine the prevalence of traumatic events and PTSD in communities in northern China, to explore the types of stressful traumatic events and the impact of these traumatic events on children and adolescents, and to investigate the effect of sociodemographic factors on PTSD. Methods A cross-sectional survey study was conducted among 6,027 students (7–17 years old) from 6 cities in Liaoning Province, China. The sample consisted of 2,853 males (47.34%) and 3,174 females (52.66%). The Essen Trauma-Inventory for Children and Adolescents (ETI-CA) Scale was used. The ETI-CA has 5 sections, which include type of traumatic events, worst traumatic event, post-traumatic symptoms, onset, duration, burden of PTSD, and present difficulties in different areas of life. PTSD symptoms were assessed with 23 items in Part 3 of the ETI-CA. Results We found that 2,068 (34.3%) of 6,027 participants experienced trauma events and 686 (33.2%) of 2,068 reported PTSD. Among trauma-exposed youth (2,068), the sudden death of close relatives (33.9%), serious accidents (20.9%), and parental divorce (15.5%) were reported as the worst traumatic events. Studies have shown that after exposure to stressful life events, more than 30% of people feel nervous or upset (39.8%), scared (33.4%), helpless (32.6%), and about 10% have headaches (15.5%), rapid heartbeat (13.3%), and dizziness (11.8%). Multivariable logistic regression analyses showed that students in middle school [OR = 1.29 (1.016, 1.637)], not a student leader [OR = 0.738 (0.618, 0.881)], and their parents in single marital status significantly predicted higher PTSD prevalence the remarried [OR = 0.474 (0.252, 0.893)], married [OR = 0.42 (0.227, 0.778)]. Conclusion The present study suggests the government to train psychological counselors in schools and communities to provide emotional and psychological support, as well as the school leaders and parents to elevate adolescents' psychological suzhi. Particularly, counseling and professional support should be given to those students whose parents are single.


. Introduction
The Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV), proposed traumatic events as exposure to one or more of the following events by personal experience, witnessing, repetition of distasteful details, or extreme experiences, involving actual death or threat of death, serious injury, or threat to the physical integrity of self or others, and intense fear, helplessness, or horror response (1).The second part of the definition in the DSM-V has been eliminated (2).
Exposure to traumatic events at least once was common in childhood and adolescence.It was reported that 63.0% of the children and 89.5% of the adolescents had ever experienced traumatic events in Linköping, Sweden (3), 60.0% of adolescents in the United States (4), 68.9% of adolescents in Mexican (5), 83.7% of children and adolescents in the Gaza Strip, Palestinian (6), and nearly all adolescents (99.7%) in Soweto, South Africa (7)."Children of Rural-Urban Chinese Migrants" reported that 47.1% had experienced traumatic events (8).
Most literature about traumatized children and adolescents came from disasters, violent injuries, war combat, and death.Approximately 11-72.8% of traumatized adolescents may develop Abbreviations: PTSD, Post-traumatic stress disorder; GDP, gross domestic product; Essen Trauma-Inventory for Children and Adolescents (ETI-CA); OR, odds ratio; M, mean; SD, standard deviation; CIs, confidence intervals.
PTSD as a result of natural disasters (20,22).Approximately 37-50% of adolescents who were exposed to physical abuse and sexual assault have met the criteria for a diagnosis of PTSD (30,31).The proportion of war-related traumatized adolescents who meet the diagnostic criteria for PTSD is as high as 36-53% (6,32,33).Traumatic events are prevalent in children and adolescents.However, traumatized children and adolescents lack effective skills to cope with traumatic events and are more likely to develop PTSD.The population of children in China reached 246 million in 2021, which is approximately accounted for one-tenth of the world's child population (34,35).The rate of PTSD was 6.7-9.7%,among Chinese rural children and adolescents with traumatic experiences (8,36).The epidemiological characteristics of traumatic events and PTSD among children and adolescents in communities of China are still unclear.
PTSD followed by Trauma exposures during early childhood could impair child development, disrupt attachment security and self-regulatory processes, and lead to poor physical and mental health outcomes in childhood and across the lifespan (37).It has been shown that adolescents with PTSD are at increased risk for additional mental health problems, including self-harm, suicide attempts, social isolation, loneliness, and functional impairments (38).The frontolimbic circuits of youth with PTSD exhibit developmental and overt abnormalities, which may contribute to an increase in threat reactivity and a decline in emotion regulation (39).PTSD in adolescence is a risk factor for longterm psychopathology, substance abuse, and quality of life deficits (40,41).
Demographic factors [e.g., age (42-44), female gender (45,46), not living with parents (47,48), living in a rural area (49), poor family functioning (50, 51), and trauma exposure history] and socioeconomic factors (e.g., low economic resources and low social support) play a role in the risk of PTSD (42, 52).Age was a contradictory factor.Both youth and older age were thought to be associated with an increased likelihood of presenting with symptoms of PTSD (42)(43)(44).
The study aimed to explore the types of traumatic events experienced, to evaluate the rates of probable post-traumatic stress disorder, and to investigate predictors of PTSD symptoms in a sample of 6,027 children and adolescents in Liaoning Province, China.We hypothesized that risk factors such as demographic variables (including education level, age, gender, grade level, whether living with parents, whether student leaders, living area, living city, parent's marital status, parent's education level, annual household income) might be associated with PTSD in Chinese children with traumatic experiences in Liaoning Province.

. . Sample size
Based on the pilot study, we calculated the sample size.Prior to the survey, questionnaires were randomly distributed to 400 students in an elementary school and a secondary school in Jinzhou City.In the pilot study, the prevalence of PTSD (p) was 33.3%.Using the following formula to calculate the sample size, α values were considered to be 0.01 and d was considered to be 0.10 × p.The intended sample size we needed for the study would have been 1,333.Finally, we recruited 6,027 participants (53).

. . Procedure
The research team assessed trauma exposure and PTSD in children and adolescents in Liaoning through a cross-sectional survey using questionnaires, from 1 June to 31 December 2013.Six cities were chosen to provide a diverse sample based on the gross domestic product (GDP) ranking.There were Shenyang, Dalian, Yingkou, Jinzhou, Liaoyang, and Dandong.Before starting the investigation, teachers handed out informed consent forms to students after the safety education session.The students took the informed consent forms home to their parents.Parents who agreed to the student's participation in the survey signed the informed consent form.The next day, teachers distributed questionnaires to students who volunteered to participate in the study and informed consent was obtained from parents.All children were informed that the questionnaire was anonymous, and their answers were strictly confidential.Researchers and trained teachers provided assistance to children and young people in completing the questionnaire and explaining any questions during the survey.All the researchers involved in the survey were trained by child psychologists.If a participant meets the criteria for PTSD or is highly symptomatic, the psychology teacher will provide psychological intervention services.Multistage stratified cluster random sampling was adopted to investigate the prevalence of traumatic events and post-traumatic stress disorder (PTSD) and the factors associated with PTSD in children and adolescents in northern Chinese communities.Researchers and trained teachers provide assistance to children and adolescents with problems during the survey.Participants and data collection procedure are presented in Figure 1.

. . Ethical considerations
This study was conducted according to the principles of the Declaration of Helsinki.All participants provided an informed consent form signed by their parents, giving their consent for the students to participate in the survey.(55).
The ETI-CA has five sections, which include type of traumatic event, worst traumatic event, post-traumatic symptoms, onset, duration, burden of PTSD, and present difficulties in different areas of life.PTSD symptoms were assessed with 23 items in Part 3 of the ETI-CA.

. . . . Types of traumatic events
This section mainly consists of identifying the type of trauma experienced by the student and whether they have ever experienced a traumatic event personally or as a witness.The types of trauma reported are categorized as follows: natural disaster, severe accident, severe illness or injury, assault by a stranger or a familiar person, sudden death of a close family member, imprisonment, sexual abuse, war trauma, neglect, and other stressful events.It contains 12 items.

. . . . The worst traumatic event
On the Traumatic Events Checklist listed in Section 1, which event was their worst experience?If the event is not included, they can override another event.The timing and subjective perception of the most severe traumatic event were also recorded.These are reported by items 13-15.

. . . . The post-traumatic symptoms
This part of the instrument consists of 23 items investigating participants' post-traumatic symptoms over the past 4 weeks, each item using a 4-point Likert scale ranging from "not at all" (0 points) to "very often" (3 points).The total score ranged from 0 to 69, with 16-26 and ≥27 representing suspected and confirmed PTSD, respectively.Higher scores indicate more severe symptoms.The Cronbach's alpha coefficient of this scale is 0.904.These items correspond to the DSM-IV criteria for Post-Traumatic Stress Disorder.
In addition, the 24th item asked respondents to identify which physical complaints they had experienced.These included stomach aches, headaches, sickness, diarrhea, tremor, dizziness, racing heartbeat, breathlessness, and seizures.The fourth part consists of 3 items.The questions were about the onset, duration, and burden of their post-traumatic symptoms under the influence of the most severe traumatic event.How burdensome this event is to you right now, on a 6-point Likert scale ranging from 0 = "not at all" to 6 = "extremely." . . . .The impact of traumatic events in di erent areas of life This section asked how difficult the student is currently in different areas.These areas include school/employment, household chores and duties, hobbies, and leisure activities, relationships with friends, relationships with family members, and sexuality.The answers to these questions are based on a 4-point Likert scale ranging from 0 = "none" to 3 = "strong".

. . Statistical analysis
Data were analyzed by IBM SPSS version 21.0 (Chicago, IL, United States).Frequencies and percentages were calculated for the categorical data.T-tests and one-way ANOVA were used to investigate the difference in the continuous variables between groups.The chi-square test was used to verify differences in the categorical variables between groups.Univariate and multivariate logistic regression analyses were used to explore the impact of factors on post-traumatic stress disorders.A two-sided P-value <0.05 was considered statistically significant.

. . Demographic characteristics
The sample size of the survey was 6,027, which consisted of 52.7% (n = 3,174) girls and had a mean age of 12.3 years (range from 7 to 17 years, SD = 1.62).Most of the students were living in rural (76.9%, n = 4,637) and lived with their parents (90.1%, n = 5,430).The demographics of the study are presented in Table 1.

. . Prevalence of traumatic events and levels of total PTSD
Of the 6,027 samples, the number of people who experienced different traumatic events was 2,068 (34.3%) during their life.The mean PTSD score for the sample that had experienced a traumatic event was 20.30 ± 13.86.
T-tests indicated that middle school students reported higher PTSD scores than elementary school students (P < 0.001).Students who lived with their parents scored significantly lower on PTSD than those who did not live with them (P < 0.05).Compared to those who were student leaders, students who were not student leaders scored higher on PTSD (P < 0.05).Those living in rural areas reported higher PTSD scores than those living in urban areas (P < 0.001) (Table 2).
One-way ANOVA indicated that students in Yingkou and Dandong reported higher PTSD scores than in other cities (P < 0.001).The oldest age group (14 to 17 years) scored significantly higher on PTSD than the older age group (P< 0.001).Compared to students in the lower grades, those in the upper grades (Grades 7-9) scored higher on PTSD (P < 0.001).Students whose parents were single reported higher PTSD scores than those whose parents were remarried and married (P < 0.01) (Table 2).

. .Distribution of di erent types of traumatic events
Table 3 shows different types of traumatic events students experience during their life.Of the 2,068 sample, the three worst traumatic events reported were the sudden death of close relatives (33.9%), serious accidents (20.9%), and parental divorce (15.5%).The three types of traumatic events witnessed by all students with the highest frequency were serious accidents (31.6%), the sudden death of close relatives (16.9%), and severe illness (14.0%).Regarding personally experienced trauma, the three types of traumatic events that all students experienced most were the sudden death of close relatives (19.3%), parental divorce (10.0%), and neglect (9.3%).The most severe interpersonal trauma experienced by girls was the same as the overall sample.The frequency of traumatic events in the three most severe personal  experiences reported by boys was the sudden death of a close family member (14.3%), other stressful events (9.9%), and severe illness/injury (9.5%).Among personally experienced traumatic events, there were statistically significant differences between boys and girls mainly in natural disasters, serious accidents, sudden death, or loss of a close person (P < 0.05).Among the traumatic events witnessed, a significant gender difference was found between boys and girls for traumatic events in natural disasters and assault by a stranger (P < 0.05).There were significant gender differences in the following worst traumatic events experienced: natural disasters, assault by a stranger, assault by a family member or someone you know, sudden death or loss of a close person, imprisonment, and sexual abuse by a stranger (P < 0.05).Details are shown in Table 3 and Figures 2-4.

. . Distribution of feelings-physical complaints-burden in the worst event
In the worst event, more than 30 % of respondents reported feeling very tense or restless (39.8%), scared (33.4%), helpless (32.6%), and physically injured themselves (31.5%).The main physical discomfort experienced by the participants was headache (15.5%), rapid heartbeat (13.3%), and dizziness (11.8%).After a stressful life event, approximately 5 % of adolescents felt strongly extremely or strongly burdened whereas 20% felt little or no impact from the traumatic event (Table 4).

. . Current di culties in di erent areas of life
Adolescents with a history of trauma seemed to be more prone to experience difficulties at school and in doing household chores, compared to hobbies and leisure activities, relationships with friends, relationships with family members, and sexuality.The fewest students reported having difficulties with sexuality ( A significant gender difference was found for personally experienced traumatic events 1, 2, 6.A significant gender difference was found for witnessed traumatic events 1, 4. A significant gender difference was found for the worst experiences of trauma 1, 4, 5, 6, 7, 8.

FIGURE
Gender di erences in personally experienced traumatic events.

FIGURE
Gender di erences in witnessed traumatic events.

FIGURE
The worst experience of traumatic events in di erent genders. .

. Traumatic events and frequency of PTSD
A chi-square analysis was performed to explore demographic differences between participants with total PTSD and those without PTSD.In the overall sample, the prevalence of confirmed PTSD was 11.4% (686 of 6,027) and the prevalence of suspected PTSD was 8.5% (511 of 6,027).Among traumatized participants, the prevalence of confirmed PTSD was 33.2% (686 out of 2,068) and the prevalence of suspected PTSD was 24.7% (511 out of 2,068) (Table 6 and Figure 5).
The differences among students with total PTSD and without PTSD were observed in the distribution of cities (χ 2 = 14.331,P = 0.014).Students in Dandong and Yingkou reported more PTSD than those in Shenyang, Dalian, Jingzhou, and Liaoyang.The frequency of PTSD diagnoses also differed significantly among students with different levels of education (χ 2 = 20.368,P < 0.001).Middle school students were more likely to meet the PTSD criteria  than primary school students.Significant differences were also found between age and PTSD (χ 2 = 23.461,P < 0.001).Students in the 14-17 age group were more likely to meet the criteria for PTSD than children in the 7-10 and 11-13 age groups.The grade is a significant influence on PTSD (χ 2 = 26.303,P < 0.001).Students in grades 7-9 were more often diagnosed with PTSD than students in grades 3-6.The difference in the living area was found to have a significant effect on PTSD (χ 2 = 7.604, P = 0.006), and students who lived in rural were more likely to develop PTSD than those who lived in urban.Furthermore, student leaders were associated with PTSD (χ 2 = 10.231,P < 0.001).Students who were not student leaders had a PTSD diagnosis more often than those who were student leaders.The marital status of parents was observed to have an effect on PTSD (χ 2 = 11.309,P = 0.004), and students with single parents were more likely to suffer from PTSD than students with remarried and married parents.

. . Factors associated with PTSD
To investigate the predictors of total PTSD, univariate logistic regression analyses were first performed by entering each demographic variable individually into the regression model (Step 1).The results showed that approximately 33.2% of the sample (n = 2,068) met the diagnostic criteria for PTSD; seven items were significantly associated with PTSD among students, including education, age, grade, student leaders, living area, remarried, married, and education status of parents (P < 0.05).Middle school students were more vulnerable to suffering from PTSD than primary school students (OR = 1.497, 95%CI: 4.363-6.422).Adolescents were more likely to suffer from PTSD with age (OR = 1.143, 95%CI: 1.081-1.209).Compared to lower grades, adolescents with a traumatic history were more likely to develop PTSD at higher grades (OR = 1.102, 95% CI: 1.051-1.156).Student leaders tend to be less likely to have symptoms of PTSD than the general student (OR = 0.752, 95% CI: 0.631-0.896).Students living in urban areas were less likely to develop PTSD than those living in rural areas (OR = 0.742, 95% CI: 0.599-0.918).Students with remarried (OR = 0.493, 95%CI: 0.263-0.921)or married parents (OR = 0.407, 95% CI: 0.221-0.750)were less susceptible to PTSD than those with single parents.Participants with parents with a master's degree or above were found to have a lower risk of PTSD than participants with parents with less than a high school education (OR = 0.500, 95% CI: 0.273-0.913).There was no significant difference in cities of different socioeconomic levels, sex, and parental annual income (P > 0.05) (Table 7).
All univariate variables that showed a relationship with the results were entered into the multivariate regression model (Step 2).Backward stepwise logistic regression was used to analyze the association between total PTSD and demographic variables.There were three variables associated with PTSD (P < 0.05), such as education, student leaders, and the marital

FIGURE
Frequencies of traumatic events and PTSD.
status of parents.Compared with elementary school students, middle school students were more inclined to have PTSD (OR = 1.290, 95% CI: 1.016-1.637).Compared with the general students, student leaders were less inclined to have PTSD (OR = 0.738, 95% CI: 0.618-0.881).The parenting marital status had a significant effect on PTSD.Compared with the students with single parents, students with remarried or married parents were less inclined to have PTSD (the remarried: OR = 0.474, 95% CI: 0.252-0.893;the married: OR = 0.420, 95% CI: 0.227-0.778).

. Prevalence of traumatic events
The first aim of the study was to offer information on the prevalence of different types of traumatic events and the associated impact of traumatic events on children and adolescents.The results showed that nearly one-third of children or adolescents (34.3%) in Liaoning, China, had experienced at least one traumatic event, which is lower than 40.1% reported in the Chinese rural sample, 60.0% reported in the U.S. national sample, and 68.9% reported in the Mexican sample (4,5,8).The result was also lower than the Swedish study (63.0% of children and 89.5% of adolescents experienced a traumatic event) (3).The highest levels of traumatic events experienced by adolescents were found in the Palestinian (83.7%) and South African (99.7%) studies (6,7).These differences in findings may be due in part to transcultural differences, natural conditions, and data collection.The reported rates of witnessed trauma exceeded the rate of personally experienced trauma.Over 30 % of boys and girls had seen an industrial fire, explosion, or serious traffic accident (such as a car, airplane, or boat), which was the most traumatic experience witnessed by individuals in the sample.Approximately 20 % of students were exposed to the loss or sudden death of relatives, which was the most traumatic experience for the individuals in the sample, with more girls than boys experiencing such traumatic events.The sudden death of a relative, industrial fire, explosion or serious traffic accident, and parental divorce were the three worst experiences reported by the participants.To our knowledge, 17.8% of the participants who were exposed to the worst traumatic event could cause a moderate and above burden.In addition, exposure to the most severe traumatic events was associated with impairment of somatic symptoms.Approximately 15.5-11.8% of the sample reported headache, dizziness, and rapid heartbeat, while diarrhea, tremors, and seizures were reported at lower rates.Over 30 % of the participants felt helpless, extremely fearful, and very tense or restless.

. . Prevalence of PTSD
The second aim of the study was to screen positive PTSD cases among children and adolescents who had experienced one or more traumatic events in their lifetimes.The findings revealed PTSD in 33.2% of children and adolescents exposed to traumatic events, which was 11.4% of the total sample.The prevalence of PTSD in our research was lower than participants who had experienced natural disasters.A meta-analysis study showed that 19.2, 30, 24.4, and 17.7% of children and adolescents suffered PTSD after earthquakes and floods over the first, second, third, and fourth 6-month periods (56).Exposure to natural disasters is associated with increased susceptibility to post-traumatic stress disorder in adolescents.This may be due to the fact that devastating natural disasters can have a devastating impact on individuals and communities, including those who are displaced, injured, or have lost loved ones or personal property (57,58).In addition, several studies report a higher prevalence of PTSD (37.0-50.0%) in victims of interpersonal trauma (e.g., sexual violence and physical abuse) than in our study (30,31).The excessive perception of life-threatening situations in children that result from interpersonal violence increases their risk of developing PTSD (48).Also, the prevalence of PTSD is even higher among children and adolescents who experienced war in Palestine (36%) and Syria (53%) (33, 59).This was probably because, children and adolescents may be exposed to challenges created by direct violence and non-violent impact due to war, such as seeing civilians killed, injured, or terrorized; being abducted, arrested, imprisoned; witnessing fierce conflicts by armed forces, artillery fire; and being forced to flee from their homes and lose their families.The wide range of results could be attributed to the type and degree of trauma exposure and the devastation of the event.
In a general community sample, our study reported a higher prevalence of PTSD (11.4%) than South African samples (4%) (32), US samples (4.7-8%) (48, 60), Malaysian samples (9.5%) and Indian samples (6.4%) (61).Many factors may contribute to crossnational differences in PTSD prevalence.One possibility to note is the psychiatric assessment instruments used.Participants in South Africa were evaluated and diagnosed according to DSM-IV criteria.
A modified version of the Composite International Diagnostic Interview (CIDI) was administered by trained lay interviewers to US adolescents to assess their PTSD prevalence.The Harvard Trauma Scale was used to assess Malaysian and Indian students' PTSD prevalence.The second possibility is that there is increased awareness of PTSD among the general public and mental health services.Many students with PTSD may be afraid to recall or report traumatic events for fear of being stigmatized, and thus, the prevalence of PTSD is more likely to decrease (62).Also, differences in methodological approaches may account for this variability, including sample size, the use of different diagnostic criteria for PTSD, and the timing of the assessment after people have been exposed to a traumatic event (63).

. . Factors of PTSD
The study showed that students in middle school had more PTSD than in elementary school.Consistent with our research, studies of children following the earthquake found that older children were more susceptible to traumatic events than younger ones (64).A similar result was also found in tornado events (65).One explanation is that junior high school students were adolescents, a time when physical and emotional changes could lead to mental and physical instability, which increased the propensity for PTSD (6).Moreover, adolescence was considered to be a period of development associated with a high risk of exposure to negative or traumatic events and vulnerability (66).Furthermore, they had to deal with more stressful (such as learning pressure) and traumatic life events (67).Most traumatized students in China were reluctant to seek professional mental health services.When they are exposed to traumatic events, they may be prone to direct their pain, sadness, and other emotions internally, which may lead to the undesirable consequence of increasing the tendency to develop PTSD (68).It is therefore necessary for the government to train psychological counselors in schools and communities to assist traumatized children and adolescents.
The study demonstrated that student leaders were found to be an important protective factor for participants' PTSD.The reason for this may be that the success of student leaders in academic and interpersonal communication contributes to positive self-perceptions and emotional experiences at school and home.As excellent student representatives, most of them have a high level of psychological suzhi, which can effectively help students cope with stressful events and promote Mental Health (11, 69).The concept of psychological suzhi is a basic, stable, and internal psychological quality formed under the influence of congenital conditions, environment, and upbringing.Psychological suzhi is an endogenous factor affecting mental health.It is negatively correlated with depression and positively correlated with life satisfaction, subjective well-being, and positive mood (69, 70).In addition, student leaders with a good sense of confidence and security predict good peer relationships, which can mitigate and prevent the effects of stressful events (71)(72)(73).Therefore, school leaders and parents need to elevate adolescents' psychological suzhi in various ways.
Another factor that can affect the level of PTSD is the parents' marital status.In line with previous studies, students with a history of trauma whose parents remain married were less likely to develop PTSD than those whose parents are single.It can be speculated that greater marital quality may be under lower parenting stress due to more household income and greater social support (74).Parents who suffer from high levels of financial stress are unable to provide coping strategies and appropriate resources for the prevention of PTSD in children and adolescents who have experienced trauma (75).As a result, single-parent families lack the time and patience to nurture their children to satisfy their basic needs (76)(77)(78).Hence, a parent raising a child alone can worsen the effects of a traumatic event on the child in different ways.Confirming findings were also found in many studies that low socioeconomic status was more likely to develop PTSD (79,80).Consequently, particularly counseling and professional support should be given to those students whose parents are single.

. . Strengths and limitations of the study
The results from the study had several limitations.First, the study relied on self-reported questionnaires, which may exist in social desirability bias and recall bias.Older students may be reluctant to disclose traumatic events that may raise sensitive issues, such as sexual abuse.Younger students may not be able to identify all traumatic experiences, such as being assaulted by a family member, especially those such as being physically attacked.Hence, face-to-face interviews and clinical assessments should be used in the future to more accurately diagnose children and adolescents with PTSD.Moreover, parental ratings may provide important information about children's functioning when young people are unreliable reporters of their behavior.Research has shown that children's PTSD is best assessed by utilizing information from multiple sources (81).Therefore, we call for more research to investigate the parents and teachers.Second, the survey used a cross-sectional design among children and adolescents in northern China.Thus, generalizations must be drawn with caution to other countries and other parts of China.Third, data were collected through the ETI-CA questionnaire and PTSD was assessed based on DSM-IV criteria.The epidemiology of children and adolescents with PTSD based on DSM-V criteria will need further investigation.In addition, the effects of traumatic event exposure may change over time due to the timing of the study endpoints, which may affect the generalizability of the findings.
Concerning the strengths, the study provides valuable evidence by using a large sample of children from families of different socioeconomic levels.Moreover, to thoroughly understand the research question, the measures of PTSD were widely applied and validated instruments.The parents may generally not be aware of all traumatic experiences, but they may also not be willing to disclose some events, particularly those such as child abuse, any mention of which may raise sensitive issues.This would result in selective underreporting of important events that could distort the results.However, both interpersonal and noninterpersonal events were reported with similar discrepancies between the samples.

. Conclusion
Our study suggested that government, schools, teachers, experts, and parents should pay more attention to trauma exposure and post-traumatic stress disorder among a community sample of children and adolescents in China and provide emotional and psychological support.It is important to design appropriate emotional and psychological support into the intervention process to prevent trauma exposure and PTSD.

FIGURE
FIGUREParticipant and data collection flow chart.
. . . .The onset, duration, and burden of PTSD The study was approved by the Ethics Committee of the Nursing Department of Liaoning Medical College (Approval Number 2013-00).
TABLE Demographic variables frequencies of the participants (N = ,).
Student leaders, usually the leaders of a class, are usually elected by the class and are also known as class representatives, peer mentors, and teacher's assistants, just like the class president, which will help them develop leadership skills.
TABLE Logistic regression analysis of the factors a ecting total PTSD among children or adolescents (N = ,).