The WHO defined health as the state of complete physical, mental, and social well-being, and not merely the absence of disease or infirmity[5]. SHS may not always correspond to either the early stage or preclinical phase of an illness, but it is typically defined as the period preceding the onset of clinical manifestations of diseases. Individuals in the early stage or preclinical period often require interventions with specific therapies aimed at preventing or delaying the onset of the disease[28]. Modifiable risk factors, in particular, play a crucial role in implementing targeted, cost-effective prevention measures for illnesses in the population. Adolescence is a critical period of physical, psychological and social adaptation. However, China's environmental pollution and rapid changes in lifestyle have widely affected people's health conditions and greatly increased the risk of SHS[9]. At the same time, SHS is also a major challenge faced by the global public health[29, 30]. With the rapid development of the social economy, various cultures, pressures, values, lifestyle behaviors, etc., swiftly infiltrate the adolescents, significantly impacting the immature physical and mental aspects, leading to an increasing prevalence of SHS among adolescents. The research findings revealed that among 1904 middle school students, a total of 197 (10.35%) were identified SHS. Previous research on people aged 15–60 in China showed that the prevalence of SHS was 46.3%, which was higher than current study[31]. And the research conducted in Chinese universities showed the prevalence of SHS among college students was 21.0%, which was also higher than current study[32]. The SHS rate among adolescents was slightly lower compared to the general population, which may be attributed to the fact that SHS tends to increase with age[12]. However, this by no means implies that SHS in adolescents should be overlooked. Instead, we should pay more attention to SHS in adolescents. Adolescents develop rapidly physically and mentally but are immature, while simultaneously facing a series of external pressures such as academic, employment, and emotional challenges, leading to a gradual prevalence of SHS[33]. SHS may be a pathway to a
whole lifespan, determining the increased cause of health risk in old age and it is recognized that early diagnosis and timely management can prevent the occurrence of SHS[34].
Adolescents with SHS often manifests in daily life as low energy and a state of fatigue, severely impacting the academic performance and healthy growth of adolescents[6]. At the same time, SHS is associated with internalizing issues such as anxiety and depression[12], consistent with the results obtained in this study focusing on the middle school students. In the present study, the prevalence of depressive symptoms and anxiety symptoms are 34.09% and 30.72%, respectively, which is consistent with those reported by other studies[35, 36]. The PS of Chinese adolescents is not optimistic. The present study showed that compared with students without PS, the prevalence of SHS among students with depression and anxiety symptoms were 91.4% and 90.9%, respectively (Table 2), which were extremely high. And through multivariate logistic regression, it was found that as the scores of GAD-7 and BDI-Ⅱ increased, adolescents were 1.33 times and 1.08 times increased risk of developing SHS, respectively (Table 3). Another finding was that as the SHS score increased, both the GAD-7 and BDI-Ⅱ scores increased in the same direction (Table 4). In addition, the five domain scores and total score of SHS were significantly higher in the groups of students who had anxiety or depression symptom (Tables 5 and 6). According to the results of this study, a strong correlation can be identified between PS and SHS. The reasons for adolescents' susceptibility to psychological issues such as depression or anxiety are complex and involve multiple factors. Firstly, physiological changes are a significant characteristic of adolescence, and these changes during this period may have a significant impact on emotional and PS. The hormonal levels fluctuate during adolescence, with an increase in the secretion of sex hormones and growth hormones promoting rapid physical growth and development, the hormonal fluctuation may lead to emotional swings[37, 38]. In addition, heavy academic pressure is a significant challenge faced by adolescents, especially in middle school stage, which may have a huge impact on the psychological well-being of Chinese adolescents[39, 40]. Adolescents need to cope with numerous exams and academic assessments, such as high school or university entrance exams, which are extremely crucial in China and are likely result in anxiety and depression among adolescents. Meanwhile, these intense competitions mean that students must perform better academically for better prospects. This kind of competition often adds a considerable amount of anxiety and pressure to them. Furthermore, middle school students may feel overwhelmed by academic burdens, including a substantial amount of homework and extracurricular tutoring, leaving them with insufficient time for physical and mental rest. Faced with these pressures, students may experience feelings of frustration, anxiety, and even depression[41]. Psychological stress is a type of negative emotional state. Chronic social psychological stress caused by long-term psychological stress may lead to SHS by the changed profiling of serum cortisol level and glucocorticoid receptor[42, 43]. Adolescents may also experience PS due to the excessive expectations from parents[44]. The intense competitions, academic burdens, physiological changes and excessive expectations affect the physical and mental health of adolescents in China, resulting in poor health status. For example, if the symptoms of depression and anxiety are not well managed, they will increase the risk of suffering cardiovascular diseases[45, 46].
In the OPH group, the proportion of sleep time less than 6 hours was lower than that of SHS group. The results of multivariate logistic regression analysis with whether had SHS as the dependent variable also showed that compared with students sleep less than 6 hours, sleeping 6–8 hours is a significant protective factor (P = 0.012) for SHS (Table 3). In addition, with the increase in sleeping time, the scores of each dimension of SHS decreased (Table 7). The explanation to the observed finding may owe to the shared common characteristics between SHS and insufficient sleep, particularly the relevant items in the questionnaires and the common predisposing factors associated with their causes. These results indicate that adequate sleeping time helps reduce the risk of SHS. Previous studies have indicated that sufficient sleep contributes to reducing psychological stress and helps maintain both physical and mental well-being[47, 48]. Sleep is an important factor in promoting physical growth and development in adolescents and helps the maintenance of normal bodily functions[48]. Moreover, numerous studies have proven that sufficient sleep helps strengthen the immune system, enabling adolescents more resistant to disease[49], and the regular sleep pattern contributes to maintaining normal metabolic functions, preventing obesity, and other metabolic issues[50, 51]. Adequate sleep also helps improve PS. It was reported previously that sufficient sleep can alleviate anxiety and depressive feelings, contributing to emotional stability and psychological well-being[52]. This, in turn, helps adolescents better cope with the pressures and challenges of daily life. For middle school students, adequate sleep is crucial for learning, memory and attention[53]. It helps enhance learning efficiency and academic performance. The current study indicates that adolescents who get less sleep are more susceptible to SHS. The coexistence of SHS and insufficient sleep will aggravate in terms of worse life quality, higher health risks, lower study efficiency and less happiness.
This research has confirmed a significant correlation between SHS and anxiety, depression among middle school students, with inadequate sleep of less than 6 hours being identified as a predictive factor for SHS. From the perspective of public health, identifying modifiable risk factors, predicting, preventing and performing early personalized interventions are highly important for preventing and reducing the risk of disease. For middle school students, physical health is just as important as mental health. SHSQ-25 can be used to screen for SHS groups, and combined with physical examination indicators, personalized interventions can be implemented in future work to extend life expectancy.
Limitations
The cross-sectional study data were derived from self-administered questionnaires. Students surveyed need to recall information about themselves, which may lead to recall bias. Additionally, regarding certain sensitive questions, there was a possibility of exaggeration or concealment, resulting in socially desirable responses and causing reporting bias. In addition, the study was a cross-sectional study, making it difficult to infer a casual relationship between PS and SHS, further longitudinal studies were needed to infer causal relationships between variables.