COVID-19-associated impact and post-traumatic stress symptoms 39 days after pandemic in a sample of home-quarantined Chinese college students: the mediating effecting of past stressful events, psychological resilience, and social support

The COVID-19 pandemic has been one of the most stressful events in recent times worldwide. Throughout the world, the main method of preventing the spread of COVID-19 has been isolation and social distancing [1]. Many countries began enforcing regional and national containment or lockdown measures starting in January 2020, to prevent the spread of the virus. In China, the implementation of the strict home quarantine measures has kept a large number of people in isolation, particularly Chinese college students who have been unable to return to school due to the pandemic. This situation also raises a number of concerns, including post-traumatic stress disorder (PTSD), which is considered a common adverse outcome in this situation [2, 3]. PTSD is a mental health condition that can occur after experiencing or witnessing at traumatic event, and it can cause symptoms like flashbacks, anxiety, and avoidance behaviors [4]. One such study reported that the prevalence of PTSD in home-quarantined college students was found to be 2.9% [5].

Some studies have suggested that traumatic stress may be due to people's past events [6]. Posttraumatic stress disorder models(pathogenic event models) and the DSM-5 diagnostic criteria [7] also suggest that traumatic stress is a response to past and largely direct exposure to specific life-threatening events, and thus do not readily account for the emerging evidence that COVID-19 is associated with PTSD symptomology. Specifically, Ikizer et al. [8] found that higher levels of perceived stress predicted PTSD symptoms, and that financial stressors, social media use, and time spent at home were associated with higher levels of posttraumatic stress. Therefore, past stressful events may be a driver of PTSD.

Several theories have been proposed to explain how past stressful events may mediate the development of PTSD [9]. One theory is that individuals who have experienced past trauma may have a heightened sensitivity to stress, such that they are more likely to perceive current stressors as threatening and experience greater distress in response to them [10]. Another theory is that past trauma may result in changes in the brain and body that make individuals more reactive to stress and less able to cope effectively with stressors [11]. In the case of COVID-19, past stressful events such as a history of trauma or adverse childhood experiences may increase an individual's vulnerability to developing PTSD symptoms in response to the stressors associated with the pandemic, such as social isolation, financial stress, and fear of illness or death [12]. By understanding the mediate role of past stressful events, mental health professionals can better assess and treat PTSD during the pandemic in individuals who have experienced traumatic events in the past.

The COVID-19 pandemic has had a significant impact on individuals daily lives, including the implementation of social distancing, quarantine, and isolation measures, which may disrupt social support networks [13] and increase the risk of developing psychological symptoms [14]. The Stress and Coping Model explain that individuals rely on coping strategies [15], such as social support, to manage stress during a crisis. However, the pandemic has presented unprecedented challenges that have made traditional coping strategies, including social support, less available, leading to increased stress [16]. Moreover, the pandemic can also impact individuals psychological resilience [17] as it presents significant stressors that challenge an individuals psychological resilience, including fear of infection, financial stress, and uncertainty about future. The Transactional Model of Stress and Coping suggests [18] that an individuals appraisal of stressful situation influences their coping response, and the COVID-19 pandemic may be perceived as a significant stressors that challenges an individuals coping resources, leading to decreased psychological resilience [19].

Psychological resilience can play a mediating role in the relationship between COVID-19 impact and PTSD [20]. Psychological resilience is defined as a multidimensional and dynamic process of successful adaptation to adversity, trauma or significant sources of stress [21]. Ruiz [22] demonstrated that individuals with high psychological resilience can use their coping skills to quickly "bounce back" from distress, while those with low psychological resilience are more susceptible to depressed and feeling overwhelmed. Studies consistently demonstrate that resilience acts as a protective factor against negative psychological outcomes [23], especially during stressful events such as pandemics [24]. For example, research has shown that people with high level of psychological resilience are less prone to depression when faced with stressful events [25] and that it is protective against PTSD [26]. Furthermore, resilience has been found to partially mediate the relationship between mental health and pandemic fatigue, as well as between emotion-oriented coping strategies and general well-being [27, 28]. Overall, psychological resilience is crucial buffer that mitigates the impact of the COVID-19 pandemic on the emotional, psychological, and mental health of individuals [29]. Mental health professionals can use this knowledge to inform the development of effective interventions that promote psychological resilience in individuals affected by the COVID-19 pandemic.

Social support is recognized as a crucial compensatory mechanism that can buffer an individuals psychological responses when confronted with challenging environments such as the COVID-19 pandemic and post-traumatic stress disorder(PTSD) [30], for example, perceived social support was found to mediate the relationship between worry about COVID-19 and psychological health, buffering the negative impact of worry on psychological well-being [31]. It comprises two facets: availability of individuals who can provide potential or actual support in term of personal resources, also known as structural and functional support [32, 33]; and an external coping strategy that enables people to deal with stress by modifying their attitudes towards social support and help-seeking [34]. Prior research indicates that the adequacy of social support is negatively related to the severity of psychological symptoms like depression [35] and positively related to hope [36], resilience [37], post-traumatic growth [38], and has even been identified as a potent protective factor against the development of PTSD following a traumatic event [39]. Consequently, social support could potentially mitigate the stress-psychological symptom nexus during the COVID-19 pandemic.

As mentioned above, previous studies confirmed that psychological resilience and social support are protective factors, and past stressful events is a risk factor for PTSD. However, the COVID-19 pandemic has resulted in a prolonged exposure to stress that is different to the stress caused by disasters in the past. First, there was a rigid coping method such as home quarantine during COVID-19 that could have led to extended exposure to stress. Second, there is uncertainties in the long-term effect of COVID-19 on psychological problems. Therefore, it is important to investigate these mediating factors in the relationship between COVID-19 and the risk of PTSD.

Compared to other social groups, college students are more vulnerable to suffer from the the psychological effects of the COVID-19 pandemic [40]. For college students, social and peer interactions were reduced due to social distancing and stay-at-home requirements, in addition to the uncertainty of future career or academic opportunities due to the lockdown, all of which further exacerbated college students' psychological distress [41, 42]. Therefore, there is an urgent need to pay attention to the psychological problems of college students during the pandemic period. To our knowledge, less studies have investigated the mediating factors in the relationship between COVID-19 and the risk of PTSD in a large sample of the home-quarantined Chinese college students. Such a study would help to fill this gap and provide suggestions for public health management. We hypothesize that the relationship between COVID-19-associated impact and PTSD risk is mediated by past stressful events, psychological resilience, and social support. The hypothesized relationship can be seen in Fig. 1.

Our study focused on the mediating effects in the association between COVID-19-associated impact and PTSD in home-quarantined Chinese college students. A positive mediating effect of past stressful events was found between COVID-19-associated Impact and PTSD, whereas psychological resilience and social support had negative mediating effects. Path model fit indices for the path model were found to be significant (β = 0.28, p < 0.001), indicating that COVID-19-associated impact indirectly affects the risk of PTSD through mediating pathways (past stressful events → psychological resilience → social support) on PTSD. Our results are consistent with previous studies [57, 58], which found that participants experienced traumatic stress symptoms as a result of COVID-19, and this was associated with direct exposure to past events that threatened death, injury or other violation. Although the stressful event is not a diagnostic criterion for PTSD in DMS-defined traumatic stress [59, 60], it can still result in levels of traumatic stress equal to or greater than of PTSD, which may explain why exposure to events such as government lockdown was associated with traumatic stress symptoms. Therefore, we should pay more attention to the impact of past stressful events on the risk of PTSD symptoms during a pandemic.

Other than the mediating effect of past stressful events, a large body of existing research has also revealed the mediating effects of social support, and psychological resilience on the association between traumatic experiences and psychological morbidity. The findings were consistent with previous studies. Accumulating evidence suggests that social support is an effective emotional regulator under conditions of traumatic stress and contributes to a reduced risk of or protection against PTSD [61, 62]. On the contrary, lower levels of social support are strongly associated with higher risk of PTSD [48]. There are two possible explanations for this: first, social support is an important resource for people to overcome the distress, allowing them to cope with the traumatic experience in a positive ways [63]; second, seeking social support is a way of coping with adversity and is considered a problem-focused coping strategy that has been shown to be effective in reducing stress. When stress and anxiety are elevated, adequate social support may help college students to maintain in healthy emotional states. Psychological resilience is defined as a personal resource for coping with or overcoming a variety of adversities and perceived stress [64]. Karatzias [65] reported that psychological resilience mediates the relationship between traumatic experiences and post-traumatic adjustment, and Duncan [66, 67] found that during stressful events, individuals are more likely to experienced negative mental and psychological outcomes if they are not equipped with sufficient levels of resilience and coping skills. In addition, several studies have found a positive association between social support and psychological resilience [5, 68], with social support being associated with greater psychological resilience and lower PTSD symptomology. This suggests that increasing social support may be a strategy for enhancing psychological resilience.

In our study, the mean (SD) PTSD (IES-R) score of the sample was 31.98 ± 14.39. Almost 53.87% of the respondents experienced posttraumatic distress ( 47.12% of the respondents scores were between 25 and 59, and 6.75% of the respondents' scores were ≥ 60). Compared to a previous study using a sample of 2485 Chinese college students quarantined after the outbreak of the COVID-19 epidemic, our PTSD rates were found to be much higher (6.75% vs 2.70%) [69]. A possible explanation could be the different study designs, the use of participants from different counties, and the different assessment methods. Multinomial logistic regression analyses showed that one's post-traumatic distress scores were associated with their gender, grade, professional and region (R² = 0.06, F = 80.54, p < 0.001). Female respondents reported significantly higher levels of post-traumatic distress than their male counterparts(mean(SD) = 13.53(4.70) vs 13.05(5.11), p < 0.001). This is consistent with the findings of previous research concluding that women are much more vulnerable to stress and more likely to develop post-traumatic stress disorder [70, 71]. Of all the students, the medical students had the highest scores on the IES-R mean (SD) = 32.23(13.50). A positive explanation could be that medical students have greater medical knowledge of novel coronavirus pneumonia, which means more stress on the epidemic during exposure. This is in line with previous research [70]. It is noteworthy that students from single-child families also experienced the highest level of post-traumatic distress mean (SD) = 32.11(14.38, t = 3.32, p < 0.05,). This may be due to a lack of interaction with family members of a similar age group during home-quarantine, but needs to be confirmed with further research. Meanwhile, the financial status of students' families is also an influencing factor on the IESR scores(the lower the annual income, the greater the pressure on families)(mean (SD) = 32.28(14.89), F = 2.71, p < 0.05). The financial status of the students' families can be partly attributed to the effective prevention and control measures taken by an important social support, as this social support is considered to be one of the most important protective factors in reducing PTSD symptoms in individuals after traumatic events [71].

The study has some limitations that should be noted. First and foremost, the current analysis used cross-sectional data, so no causal claims can be made. In addition, we did not examine the long-term effect of COVID-19-associated impact on the risk of PTSD. Nevertheless, we used a large sample size covering more than 30 cities in China; this convenient sampling method may have introduced a bias in the diversity of the sample and resulted in underrepresentation of respondents. Finally, this study examined the mediating effects in the association between COVID-19-associated impact and PTSD in home-quarantined Chinese college students and did not compare the situation when the participants returned to campus or the effects of the ongoing, prolonged nature of the pandemic.

Our findings highlight the impact of the past stressful events on PTSD, suggesting that assessment of stressful events in students during the pandemic is necessary to reduce the risk of PTSD. Recommendations for further interventions include: (1) more attention needs to be paid to those who have experienced past stressful or negative events in the past, medical students, female students, students from single-child families and those with lower financial status, and by providing a sense of greater emotional security, thereby reducing their stress levels and enabling them to adapt effectively during the pandemic; (2) provide more social support needs to be provided to college students suffering from psychological distress by implementing theory-tested interventions or online programme, such as online workshops and on-demand counselling. This will increase the opportunities for students to express their feelings and concerns and openly discuss their experiences and challenges with their families; (3) establish a comprehensive psychological curriculum system in universities or colleges in China should be built to develop psychological resilience and promote the level of mental health among college students.