Adverse childhood experiences (ACEs) refer to negative events that an individual experiences in childhood that cause harm or threat to their mental and physical health [1,2]. There are three categories of ACEs: abuses (physical, emotional, sexual), neglects (physical, emotional), and household dysfunctions (family history of mental illness, incarceration, substance abuse, divorce, or domestic violence) [3,4]. Adults with a history of ACEs tend to have more short-term and long-term health problems and higher premature deaths than those without such a history [5] through differences in physiological development and health-damaging behaviors [6]. History of ACEs is also associated with depression [7] among children [8], university students [9,10], as well as homosexual men [11].

However, individuals who experienced ACEs can also undergo positive changes [12]. These positive changes are referred to as positive growth [13,14]. Similarly, those who have experienced trauma can undergo Posttraumatic growth, and those who have faced adversity can undergo adversarial growth [15,16].

Positive growth is associated with environmental conditions (type and severity of adverse event, elapsed time since event, previous life stressors), social factors (social support, religious involvement), psychological processes (rumination, coping), and positive mental health resources (hope, optimism, and self-esteem) [17,18].

The OTHERS(S) model for personal development suggests that promoting 8 core resources (i.e., the namesake of the acronym) can help promote Posttraumatic growth: Optimism, True meaning, Humor, Emotional intelligence, Resilience, Spirituality, and Self-confidence [19]. Relatedly, character strengths refer to the positive, trait-like capacities for thinking, feeling, and behaving in ways that benefit oneself and others [20]. Nearly all of the 24 types of character strengths include core resources mentioned in the OTHERS(S) model, and thus can be used as the model’s substitute measures. Previous studies have found positive associations between character strengths and Posttraumatic growth and valued outcomes (e.g., thriving, well-being, life satisfaction) [21]. Character strengths also helped to moderate the association between trauma and mental health issues such as depression [22–26].

University years (generally, when a person is 18 to 22 years of age) are a developmentally crucial period and a turbulent time whence the first onset of a broad range of mental disorders generally appears [27], especially among those with ACEs [28]. Approximately one-fourth of students in the People’s Republic of China experience anxiety [29]. However, mental health care for Chinese university students is complicated by misconceptions, stigma, low mental health literacy, and difficulty in accessing care [30]. Although a previous study found that Chinese cultural values of collectivism, deference to authority, and familyism influenced character strengths among health facility patients [31], Chinese cultural values, particularly those centered on Confucianism (e.g., deference to authority, modesty, harmony, and collectivism) also limit the ability to generalize findings from studies conducted in Western countries [32]. For example, youths who experienced abuse may regard their experience not as a traumatic experience but as a regular part of their family’s dynamics [33]. Growth from such experiences could be considered not as Posttraumatic or post-adversity growth but rather as part of a normal developmental process.

However, despite the vast literature on ACEs in high-income countries [6,34], few such studies have been conducted in China. Moreover, existing research in China tends to explore ACEs from the perspective of trauma [28–30]. Thus, there exists a knowledge gap on the association between ACEs, character strengths, positive growth, well-being, and depressive symptoms among university students in China. Such findings can provide empirical evidence for stakeholders in undergraduate mental health.

The objectives of this study are 1) to estimate the prevalence of ACEs among undergraduate students in Southern China; and 2) to assess the extent which mental health outcomes (positive growth, well-being, and depression) are associated with ACEs and character strengths among undergraduate students in Southern China.

After receiving the questionnaires, the research assistant examined their completion and validity. Investigators considered questionnaires with less than two-thirds of the questions answered to be incomplete. Investigators excluded 5 participants (0.6%) who did not finish the ACE questionnaire and 28 participants (3.6%) who did not meet the other sections. The research assistant entered data from the remaining questionnaires into an electronic dataset.

We used descriptive statistics to describe the prevalence of ACEs and their co-occurrence among the study participants. We used the chi-square test of independence to compare the socio-demographic characteristics between participants with ACE(s) and those with no ACE. To assess the extent which ACEs and character strengths were associated with positive growth, well-being, and depressive symptoms, we used univariate (presence or absence of history of ACEs was the independent variable; positive growth, well-being, depressive symptoms were the dependent variables) and multivariate linear regressions (six domains of character strengths were the independent variables; positive growth, well-being, and depressive symptoms were the dependent variables). We identified confounders for multivariate linear regression based on factors associated with adverse childhood experiences as identified using the chi-square test of independence, as mentioned previously.

We sent invitations to 1400 students, with 588 (42%) males and 812 (58%) females. Then, 1103 students answered the invitation, 784 agreed to fill out the questionnaire, and 779 students finished the questionnaires. Among the 779 students who completed the questionnaire, 283 (36.3%) were males, 439 (56.4%) were females, and 57 (7.3%) did not indicate their gender. Participants who reported ACEs were more likely than participants who did not report ACEs to be female, to come from families with income of less than $700 per month, and to document a history of having received counseling (Table 1).

Of the 779 students who finished the questionnaire on ACEs, 250 students (32.1%) reported having experienced one or more ACEs, and approximately 13% of the participants said having experienced two or more ACEs. Among participants who reported ACEs, the most popular ACE was emotional abuse, followed by emotional neglect and parental divorce. The most common co-occurring ACE was also emotional abuse (Table 2). The number of experienced ACEs ranged from 1 to 5, and the most common age range when ACE was first experienced was 7 to 12 years old.

Compared to participants with no history of ACE, participants with a history of ACEs had significantly lower positive growth scores (Adjusted regression coefficient Beta = −0.20; 95% CI = −0.37, −0.02; p = 0.03*), significantly lower well-being scores (Adjusted Beta = −1.13; 95% CI = −2.04, −0.23; p = 0.014*), and marginal significantly higher depressive symptoms scores (Adjusted Beta = 0.48; 95% CI = −0.05, 1.02; p = 0.072) after adjusting for confounders (history of receiving counseling, gender, family income, and level of academic achievement) (Table 3).

Associations between domains of character strength and mental health outcomes were heterogeneous (Table 4). Positive growth was significantly associated with humanity, wisdom, vitality, and courage. Well-being was significantly associated with humanity, temperance, and vitality. Depressive symptoms were associated with vitality and courage. Vitality was the only domain that was significantly associated with all three outcomes.

In this cross-sectional study, we described the prevalence and patterns of ACEs among university students in Southern China. We also found that positive growth, well-being, and depressive symptoms were associated with ACEs and various domains of character strengths. The findings of this study provide potentially helpful basic information for stakeholders in student mental health and also have implications for future intervention development.

The prevalence of ACEs among our study participants was lower than that among college students in the United States [50,51], Zambia [52], and Eritrea [53]. However, domestic violence and family dysfunctions are not commonly reported or discussed in public in China due to the perception of being a “private matter” and the fear of “losing face”. If the influence of such social desirability was present in our study, then the prevalence of ACEs could have been underestimated.

The proportion of students with more than 4 ACEs in our study was lower than in other studies. Students with multiple ACEs might have a lower chance of attending university, as ACEs are associated with health problems [5], reduced intelligence [54], and cognitive deficits [55] during childhood and adolescence. Thus, our findings are generalizable only to university students in similar settings.

History of ACEs was negatively associated with positive growth and well-being. These findings were similar to those of previous major studies that ACEs were associated with poorer mental health [6–9,56]. However, the outcomes of our study were measured using a self-reported questionnaire with no probing. Such under-reporting could have introduced information bias to the study findings.

Domains of character strengths were associated with positive growth, well-being, and depressive symptom scores, with vitality being significantly associated with all three outcomes. The findings of our study were consistent with those of a survey among earthquake survivors in Sichuan, China [57], which found an association between character strengths and Posttraumatic growth. Vitality explained 32% of the variance in post-traumatic or positive growth among those with indirect trauma. According to our exploratory factor analysis, vitality included hope and zest. Peterson and colleagues also found that hope and zest are strongly associated with posttraumatic growth among those who have experienced at least one traumatic event [21]. It is possible that positive growth and well-being can be promoted among university students and depressive symptoms can be relieved through interventions involving hope and zest. Character strengths-based intervention (CSI) is an intervention in positive psychology that aims to identify, use, and develop character strengths [22,23]. Future studies should consider incorporating hope and zest into CSI as a way to promote growth and mental health among university students with ACEs.

Positive growth was significantly associated with humanity, wisdom, vitality, and courage. These associations indicated that identifying, using, and developing the following strengths might promote positive growth among university students with ACEs: appreciation of beauty and excellence, gratitude, kindness, spirituality, citizenship, love, prudence, social intelligence, perspective, open-mindedness, self-regulation, leadership, zest, hope, brave, creativity, love of learning, integrity, persistence, and curiosity. Well-being was significantly associated with humanity, temperance, and vitality. Thus, identifying, using and developing the following strengths might increase well-being among university students with ACEs: appreciation of beauty and excellence, gratitude, kindness, spirituality, citizenship, love, fairness, forgiveness, humility/modesty, zest, and hope. Depressive symptom was associated with vitality and courage, which suggested that identifying, using, and developing the following strengths might decrease depressive symptoms among university students with ACEs: zest, hope, bravery, creativity, love of learning, integrity, persistence, and curiosity.

All factors but humor had a significant association with one of the outcomes among positive growth, well-being, and depressive symptoms. Therefore, a long-term intervention to identify, use, and develop all 24 character strengths as a course might be a possible way to support university students with ACEs.

A number of limitations existed in our study. Firstly, the study’s cross-sectional design did not allow for causal inference. Secondly, participants might not have been able to recall adverse childhood experiences, potentially introducing information bias into the study findings. Thirdly, our survey was conducted in a classroom on campus with the instructor located at the back of the classroom, which could have invoked reactivity and social desirability bias, potentially contributing to the under-reporting of ACEs. Lastly, our participants were students at one university in Southern China. The findings of the study might have limited generalizability to other populations. These caveats should be considered in the interpretation of the study findings.

The prevalence of ACEs among university students in Southern China was relatively high. ACEs were negatively associated with positive growth, and well-being and marginally positively related to depressive symptoms. In contrast, the vitality domain of character strength was the opposite, and positively related to positive growth and well-being and negatively associated with depressive symptoms. The findings of this study contributed empirical evidence for stakeholders in university mental health and can potentially inform the development of future interventions. However, caveats regarding lack of temporality, selection bias, social desirability bias, and lack of generalizability should be considered in the interpretation of the study findings.