Abstract
Background
Military personnel face more stresses and challenges, and they are at greater risk of insomnia compared to the general population. Mental health is one of the primary ways of managing insomnia. However, there are few studies regarding the mediator in the two variables among this population. This study aimed to investigate the insomnia, mental health literacy, and mental health in young soldiers, to explore the correlation of the three variables and to verify the mediating role of mental health literacy between mental health and insomnia.
Methods
The cross-sectional study was conducted from March 2023 to March 2024. A total of 2375 soldiers was surveyed using the General Information Questionnaire, Insomnia Severity Index (ISI), 12-Item General Health Questionnaire (GHQ-12), and National Mental Health Literacy Questionnaire (NMHLQ). The data were processed using descriptive analysis, Mann-Whitney U test, Kruskal-Wallis H test, Spearman’s correlation analysis, stepwise regression analysis, and a mediation analysis.
Results
The questionnaire of 2297 participants was valid with an effective rate of 96.72%. The majority of participants were male (2281, 99.30%). The mean age of participants was 23.49 ± 2.51years (range 18–35). The total score of ISI was 1 (0, 5), with a high occurrence rate of insomnia at 14.85%. The mental health displayed a significant positive correlation with insomnia (r = 0.333, P<0.001). Furthermore, the mental health literacy and its two dimensions—NMHLQ-mental health awareness (NMHLQ-A) and NMHLQ-identification and response to mental illness (NMHLQ-I) exhibited significant negative correlations with both mental health and insomnia (r=-0.346∽-0.074, P<0.001). Before and after adjusted control variables, the NMHLQ-A and NMHLQ-I played partial mediating role between mental health and insomnia, and the mediating effect ratios attributable to the NMHLQ-A were 17.79% and 17.41%, whereas to the NMHLQ-I were 2.33% and 2.20%.
Conclusions
Our findings highlight the potential negative impacts of mental health literacy on the insomnia of young soldiers directly and indirectly. Especially, NMHLQ-A and NMHLQ-I play partial mediating role between mental health and insomnia. According to these findings, Psychological service workers can develop and implement highly individualized effective interventions to improve young soldiers’ mental health and sleep quality.
Keywords: Insomnia, Mental health, Mental health literacy, Young soldiers
Introduction
Insomnia is a disorder characterized by difficulty in falling or maintaining sleep [1]. Over one-third of the world’s population reportedly suffers from insomnia [2, 3]. In China, it is reported that 15.0-29.2% of the general population and 11.36-67.6% of military personnel suffer from insomnia, respectively [4–10]. Despite variations in measures, target populations, and screen criteria employed, the assessment of insomnia consistently exhibited a notably high prevalence of the disorder [2–10]. If insomnia becomes chronic, it can result in a lack of concentration, declined quality of life, reduction in productivity at work, as well as mental and physical health issues, with potentially severe ramifications [11–13]. For example, the individuals with severe insomnia are more prone to anxiety [14], depression [15], and suicidal ideation [16]. Particularly for military, these consequences can have adverse effects on morale and military preparedness, leading to premature discharge intention from service [17]. Further, insomnia may serve as an indicator of compromised health, potentially leading to higher medical costs and more economic losses [1, 17]. As the foundation of the military, young soldiers face a variety of unique occupational stressors and challenges that impact their sleep quality [13, 18, 19]. These include finding a delicate equilibrium between family commitments and the demanding nature of their careers, enduring rigorous training regimens, and grappling with the prolonged separation and dangers inherent in their line of work [13]. While numerous mental health assessments and educational initiatives are currently being conducted to provide services for this population, resources specifically designed to enhance their sleep quality through mental health literacy are limited. Therefore, it is necessary to verify the potential intervenable factor between mental health and insomnia in young soldiers as yet unexplored.
Mental health is a significant predictor of insomnia, to a large extent, it determines sleep quality [8, 13, 20–22]. Compared with the general population, military personnel, facing challenges including but not limited to round-the-clock shifts, high-lever alertness, and high-risk working environment, confront distinctive hurdles in preserving good mental well-being [13]. Studies showed that anxiety, depression, and stress represented prevalent mental health issues within the armed forces, substantially heightening the risk of developing insomnia [10, 17–20]. Considering the dynamic changes of military mental health, difficulty of regular monitor covering all staff, and challenges of addressing occupational mental health problems within short time, it is imperative to pinpoint a protective factor that connect mental health and insomnia among young soldiers, and formulate effective interventions aimed at preventive treatment of insomnia in this population.
Mental health literacy is considered a potential mental health resource according to resource conservation theory [23, 24], with the capacity to shield individuals from stressors and adversities, as well as mitigate and avert detrimental psychological issues [25]. The concept of mental health literacy was first introduced by Jorn in Australia involved not only the knowledge and beliefs of individual identification, management and prevention of mental problems, but also the appropriate help in those with mental disorders, and the formation of mental health promotion skills and behaviors [26, 27]. Studies found that high mental health literacy enhanced one’s comprehension and ability to cope with psychological issues [28]. Additionally, it aided individuals in overcoming undesirable behaviors, fostering healthy lifestyles, and enhancing their mental well-being [29]. Numerous studies have shown that improving mental health literacy can reap valuable benefits for individuals’ mental health in a short period of time [30–32]. The mental health literacy as a mediating variable in the correlation between mental health and insomnia, especially considering the accessible, shareable, and intervenable of mental health resources, might offer novel perspectives and strategies for preventive treatment of insomnia.
However, there is currently a limited amount of research on the relationship between mental health literacy, mental health, and sleep quality. Studies on college students has shown that low mental health literacy was significantly associated with high occurrence of psychological problems such as anxiety and depression [33, 34]. Furthermore, a study focused on adolescents indicated a significant negative relationship between mental health literacy and the occurrence of depressive symptoms [35]. Moreover, there was a positive correlation between mental health literacy and COVID-19 related stress [29]. Similarly, a study involving medical students revealed that sleep problems mediated both the direct and indirect effects on the association between low mental health literacy and depressive symptoms [36]. Nevertheless, the unique occupational attributes inherent to young soldiers, characterized by qualities like obedience, preparedness, and vigilance, suggest that conclusions drawn from studies involving other populations may not suit the military context. According to the cognitive model of insomnia, incorrect sleep-related cognitions, attitudes, and negative emotions can cause insomnia, which can gradually be improved through cognitive behavior and form a good sleep habit [37]. Based on the existing studies and the model of insomnia, it was hypothesized in this study that mental health may improve sleep quality by enhancing mental health literacy. Therefore, we proposed that mental health literacy can serve as a mediator of the association between mental health and insomnia in young soldiers.
Methods
Ethical approval and informed consent
This study was approved by the Ethics Committee of Chinese PLA No.991 Hospital (991YJ-202206), and informed consent was obtained from all the subjects involved in the study.
Study subjects and design
We conducted the cross-sectional study between March 2023 and March 2024. A total of 2375 young soldiers were included by the convenience sampling method. The inclusion criteria were: (1) informed consent and voluntary participation in this survey; (2) age ranging from 18 to 35 years old; and (3) without previous history of mental illness. The exclusion criteria were as follows: (1) with previous or current mental illness diagnosed by doctors; (2)with inconsistent or missing answers; (3) duplicate IP addresses; and (4) completion time of less than 3 min or more than 50 min. Prior to commencement of the study, all investigators underwent a standard training to ensure participants were provided with a unified explanation regarding the purpose and procedures of the survey. The QR code was printed and distributed to all participants who uniformly centralized and completed the online questionnaire via WeChat. After collecting the completed questionnaires, a quality control check was made on the same day to ensure that all participants met the inclusion criteria and none of the exclusion criteria.
Estimation of sample size
According to Kendall’s sample size estimation method, a sample size should be 5 to 10 times the number of independent variables [38]. This study encompassed a total of 16 independent variables, including 11 general information questionnaire indicators, an insomnia severity index, a 12-item general health questionnaire, and 3 national mental health literacy questionnaire dimensions. We calculated the sample size with 10 times the number of variables and taking into account 20% invalid questionnaires, the study required at least 192 samples. Based on this calculation, the size of our sample was deemed adequate.
Data sources and measurement
General Information Questionnaire
The self-designed questionnaire included social and demographic characteristics (age, gender, educational level, marital status, and whether the individual was an only child), lifestyle factors such as alcohol consumption, smoking, sedentary behavior (defined as sitting for more than two hours without movement or position change), the mean frequency of weekly late nights (defined as going to bed after 11 pm) and movements. Additionally, current illnesses were defined as “diagnosed in hospitals or outpatient clinics” and included for the assessment.
Insomnia Severity Index (ISI)
The ISI is a brief and effective instrument to evaluate the severity of insomnia symptoms in the past 2 weeks [7, 8, 13, 39]. It comprises a single dimension encompassing 7 items, each item scores on a 4-point Likert scale, with total score range from 0 to 28 points. The total score of 0–7, 8–14, 15–21, and 22–28 indicates absence of insomnia, mild insomnia, moderate insomnia, and severe insomnia, respectively [7, 8]. Notably, the Chinese version of the ISI demonstrated a Cronbach’s alpha reliability of 0.843 [39], whereas the current study indicated a higher value of 0.908.
The 12-Item General Health Questionnaire (GHQ-12)
The GHQ-12 is a suitable, reliable and valid tool to assess general mental health and well-being of non-psychotic cases around the world [40–43]. It comprises a single dimension encompassing 12 items, and each item has 4 response options. The 2 responses reflecting an improvement compared to the usual situation can be scored 0-point, while the 2 responses reflecting an aggravation will be scored 1-point. An overall cumulative score of 12 items ≥ 4 signifies poor mental health [40, 43]. The Cronbach’s alpha reliability of the Chinese version of the GHQ-12 was 0.887 [43], while it was 0.739 in the present study.
National mental health literacy questionnaire (NMHLQ)
The NMHLQ is compiled by the Institute of Psychology of the Chinese Academy of Sciences for assess the mental health literacy status of Chinese residents [44]. The 44-item survey consists of 3 dimensions of questions relating to mental health literacy: knowledge judgment questions, self-assessment questions, and case study questions. Knowledge judgment questions mainly assess mental health knowledge (hereinafter referred to as the “mental health knowledge dimension”), with a total of 20 items, each with a score of 0 or 5 points, and the total score is 100 points. Achieving a score of ≥ 80 on this dimension indicates meeting the standard. The self-assessment questions mainly assess health awareness and behavioral habits (hereinafter referred to as the “mental health awareness dimension”), with a total of 8 items, each with a score of 1 to 4 points, and the total score is 32 points. Achieving a score of ≥ 24 on this dimension indicates meeting the standard. Finally, the case study section probes into the identification and response to mental illness (hereinafter referred to as the “mental illness identification and coping dimension”), with a total of 2 cases, each with 8 items, having a score of 0 or 5 points, and the total score is 40 points. Achieving a score of ≥ 28 on this dimension indicates meeting the standard. A higher score of the questionnaire, a better level of mental health literacy. When the scores of all three dimensions simultaneously meet the standards, the mental health literacy has reached the standard. The Cronbach’s alpha of the scale in this study is 0.852.
Statistical analysis
All data were statistically analyzed using IBM SPSS Statistics version 26.0 for Windows. The enumeration data were expressed as frequency and percentage. The measurement data that conformed to the normal distribution were expressed as mean ± standard deviation (mean ± SD), whereas data that did not conform to the normal distribution were expressed as median and interquartile range [M (P25, P75)]. Given the non-normal distribution of insomnia scores among young soldiers, the Mann-Whitney U test was used to compare two independent samples, and the Kruskal-Wallis H test was used to compare multiple independent samples. Spearman’s correlation analysis was conducted to explore the correlation between insomnia, mental health, and mental health literacy. A stepwise multiple linear regression analysis was used to analyze the influencing factors of insomnia. Additionally, the bootstrap method was utilized to assess the mediating effect of mental health literacy on the relationship between mental health and insomnia among young soldiers. A statistically significant difference was defined as P < 0.05.
Results
General Information
A total of 2,375 individuals completed the questionnaire. Subsequent data screening resulted in the exclusion of 78 participants (3.28%) due to specified criteria, comprising 4 respondents who exceeded the time requirement, and 74 others with inconsistent responses. Consequently, the valid response rate was 96.72%. The final sample comprised 2,297 young soldiers aged 18 to 35 years, with a mean age of 23.49 years (SD = 2.51 years). General information of the participants is presented in Table 1.
Table 1.
General Information and univariate analysis of insomnia score (n = 2297)
| Variables | N(%) | Score(Mean rank) | Z/H | P | |
|---|---|---|---|---|---|
| Age (years) | -2.722** | 0.006 | |||
| 18∽23 | 1228(53.46) | 871.05 | |||
| 24∽35 | 1069(46.54) | 951.96 | |||
| Gender | -0.498 | 0.618 | |||
| Male | 2281(99.30) | 1179.56 | |||
| Female | 16(0.70) | 1069.56 | |||
| Education level | -2.966** | 0.003 | |||
| ≤Junior college | 1941(84.50) | 1132.05 | |||
| ≥Bachelor degree | 356(15.50) | 1241.44 | |||
| Marital status | -0.554 | 0.580 | |||
| No | 1257(54.72) | 1155.72 | |||
| Yes | 1040(45.28) | 1170.88 | |||
| Whether the individual was an only child | -1.301 | 0.193 | |||
| No | 1527(66.48) | 1136.66 | |||
| Yes | 770(33.52) | 1173.46 | |||
| Smoking habit | -3.310** | 0.001 | |||
| No | 961(41.84) | 1096.90 | |||
| Yes | 1336(58.16) | 1186.47 | |||
| Alcohol consumption habit | -4.665*** | <0.001 | |||
| No | 2085(90.77) | 1129.17 | |||
| Yes | 212(9.23) | 1344.30 | |||
| Sedentary behavior | -10.650*** | <0.001 | |||
| No | 1310(57.03) | 1025.59 | |||
| Yes | 987(42.97) | 1312.79 | |||
| Mean frequency of weekly late nights | 195.419*** | <0.001 | |||
| Few | 1082(47.10) | 964.58 | |||
| 1∽3 times | 737(32.09) | 1238.67 | |||
| >3 times | 478(20.81) | 1728.21 | |||
| Mean frequency of weekly movements | 53.513*** | <0.001 | |||
| Few | 74(3.22) | 1766.13 | |||
| 1∽3 times | 521(22.68) | 1282.97 | |||
| >3 times | 1702(74.10) | 1094.20 | |||
| Suffering from illness | |||||
| No | 1733(75.45) | 1061.47 | -11.494*** | <0.001 | |
| Yes | 564(24.55) | 1717.96 | |||
| Respiratory infection | 217(9.45) | ||||
| Training injury | 182(7.92) | ||||
| Oral disease | 113(4.92) | ||||
| Others | 52(2.26) | ||||
*p < 0.05, **p < 0.01, *** p < 0.001
Scores of insomnia
The total score of ISI was 1 (0, 5), revealing that 341 individuals (14.85%) experienced at least mild insomnia. Out of the total participants, 290 (12.63%) displayed mild insomnia (8–14), 42 (1.83%) had moderate insomnia (15–21), and 9 (0.39%) exhibited severe insomnia (22–28). There was a statistically significant difference for the insomnia score in age (Z=-2.722, P = 0.006), education level (Z=-2.966, P = 0.003), alcohol consumption (Z=-4.665, P = 0.000), smoking (Z=-3.310, P = 0.001), sedentary behavior (Z=-10.650, P = 0.000), mean frequencies of weekly late nights (H = 195.419, P = 0.000) and weekly movements (H = 53.513, P = 0.000), and suffering from illness or not (Z=-11.494, P = 0.000).
Data of mental health and mental health literacy
Table 2 presents the status of mental health and mental health literacy. The GHQ-12 had a score of 0 (0, 0), and 1% of the participants were identified as poor mental health. The NMHLQ had a total score of 117 (103, 129), with 5.05% of the individuals meeting the standard; the mental health knowledge dimension achieved a score of 55 (45, 65), with 175 individuals meeting the standard, representing 6.31% of the total; in the mental health awareness dimension, a score of 32 (27, 32) was attained, with 2,104 individuals meeting the standard, accounting for 91.60%; regarding mental illness identification and coping, a score of 30 (25, 34) was recorded, with 1,445 persons meeting the standard, constituting 62.91% of the sample.
Table 2.
Spearman’s correlation of the independent variables in young soldiers (n = 2297)
| Independent variables | M(P25, P75) | % | The GHQ-12 score | The ISI score | ||
|---|---|---|---|---|---|---|
| r | P | r | P | |||
| NMHLQ | 117(103, 129) | 5.05 | -0.078*** | <0.001 | -0.117*** | <0.001 |
| NMHLQ-mental health knowledge | 55(45, 65) | 6.31 | -0.035 | >0.05 | -0.019 | >0.05 |
| NMHLQ-mental health awareness | 32(27, 32) | 91.60 | -0.208*** | <0.001 | -0.346*** | <0.001 |
| NMHLQ-identification and response to mental illness | 30(25, 34) | 62.91 | -0.074*** | <0.001 | -0.119*** | <0.001 |
*** p < 0.001
Spearman’s correlation analysis of mental health, mental health literacy and insomnia
Significant positive correlation was displayed between the GHQ-12 and the ISI (r = 0.333, P<0.001). Additionally, the NMHLQ and its mental health awareness and mental illness recognition and coping dimensions exhibited significant negative correlations with both GHQ-12 and ISI (r=-0.346∽-0.074, P<0.001), as presented in Table 2.
Stepwise regression analysis of factors influencing insomnia
The study employed multiple linear stepwise regression analysis to investigate the relationship between the ISI score and a comprehensive set of independent variables. These independent variables comprised eight prominent factors identified in Table 1, as well as scores from the GHQ-12, mental health awareness, and mental illness identification and coping, as determined by Spearman’s correlation analysis. Details regarding the assignment of these independent variables are provided in Table 3. Finally, the 8 statistically significant variables that remained in the analysis as presented in Table 4, which explained 26% of the total variance of insomnia.
Table 3.
Independent variable assignment table (n = 2297)
| Independent variable | Assignment |
|---|---|
| Age | <24 = 0, ≥ 24 = 1 |
| Education level | ≤Junior college = 0, ≥Bachelor degree or above = 1 |
| Smoking habits | No = 0, Yes = 1 |
| Alcohol consumption habits | No = 0, Yes = 1 |
| Sedentary behavior | No = 0, Yes = 1 |
| Mean frequency of weekly late nights | Few = 0, 1∽2 times = 1, ≥3times = 2 |
| Mean frequency of weekly movements | Few = 0, 1∽2 times = 1, ≥3times = 2 |
| Suffering from illness | No = 0, Yes = 1 |
| The score of GHQ-12 | Original value |
| The score of NMHLQ-mental health awareness | Original value |
| The score of NMHLQ-identification and response to mental illness | Original value |
Table 4.
Stepwise regression analysis of insomnia (n = 2297)
| Independent variable | B | SE | Beta | t | P |
|---|---|---|---|---|---|
| Constant | 9.372 | 0.697 | 13.437 | 0.000 | |
| Alcohol consumption habits | 0.669 | 0.268 | 0.046 | 2.494 | 0.013 |
| Sedentary behavior | 0.878 | 0.165 | 0.103 | 5.325 | 0.000 |
| Mean frequency of weekly late nights | 0.930 | 0.106 | 0.171 | 8.808 | 0.000 |
| Mean frequency of weekly movements | -0.398 | 0.152 | -0.049 | -2.624 | 0.009 |
| Suffering from illness | 1.299 | 0.182 | 0.133 | 7.130 | 0.000 |
| Overall levels of mental health | 1.205 | 0.104 | 0.218 | 11.578 | 0.000 |
| NMHLQ-mental health awareness | -0.207 | 0.021 | -0.188 | -9.677 | 0.000 |
| NMHLQ-identification and response to mental illness | -0.045 | 0.012 | -0.068 | -3.638 | 0.001 |
R2 = 0.262, adjusted R2 = 0.260;F = 101.641, P<0.001。
Mediation effects of mental health literacy on the association between mental health and insomnia
Table 5 displays two models utilized in this research to investigate the mediating effect, one without control variables (Model 1) and the other with control variables (Model 2). Harman’s one-way test was utilized to test common method bias for all items of the questionnaire. The first common factor explained 12.86% of the variance, less than the threshold of 40% [45], indicating no significant common method bias in the data. Further, the bootstrap method was employed, involving 5000 random samples and repetitions. The findings displayed in Model 1 demonstrated that the mental health awareness dimension of mental health literacy showed a mediation effect with a value of 0.326, which decreased to 0.226 in Model 2. The corresponding mediation effect ratios were 17.79% and 17.41%, respectively. The mediation effect values of mental illness identification and coping in Model 1 and Model 2 were 0.043 and 0.034, with mediation effect ratios of 2.33% and 2.20%, respectively. In addition, five control variables played a direct and indirect mediating role between mental health and insomnia, including the alcohol consumption habits (effect = 0.769, t = 2.675), sedentary behavior (effect = 1.006, t = 5.371), mean frequency of weekly late nights (effect = 0.934, t = 7.873), mean frequency of weekly movements (effect=-0.332, t=-1.992), and suffering from illness (effect = 1.350, t = 6.489). Figures 1 and 2 demonstrate the mediating influence of mental health literacy on the relationship between mental health and insomnia in a comprehensive manner.
Table 5.
Mediating effects of NMHQ on the association between GHQ-12 and ISI (n = 2297)
| Model | Pathway | c | a*b | c’ | SE | 95%CI | Efficiency ratio(%) |
|---|---|---|---|---|---|---|---|
| Model 1 | GHQ-12→NMHLQ-A→ISI | 1.834 | 0.326 | 1.465 | 0.052 | 0.231∽0.433 | 17.79 |
| GHQ-12→NMHLQ-I→ISI | 1.834 | 0.043 | 1.465 | 0.016 | 0.016∽0.077 | 2.33 | |
| Model 2 | GHQ-12→NMHLQ-A→ISI | 1.565 | 0.226 | 1.305 | 0.044 | 0.174∽0.318 | 17.41 |
| GHQ-12→NMHLQ-I→ISI | 1.565 | 0.034 | 1.305 | 0.017 | 0.011∽0.066 | 2.20 |
Model1: Dependent variable is ISI score, independent variable is GHQ-12 score, the mediating variables were mental health awareness and identification and response to mental illness
Model 2: On the basis of model 1, 11 control variables were comprised, such as age, gender, education level, marital status, being an only child, smoking, drinking, sedentary behavior, mean frequency of weekly late nights, mean frequency of weekly movements, and suffering from disease
NMHLQ-A: NMHLQ-mental health awareness, NMHLQ-I: NMHLQ-identification and response to mental illness
C: total effect, a*b: indirect effect, c’: direct effect
Fig. 1.
NMHLQ as a mediator of the relationship between mental health and insomnia
Fig. 2.
NMHLQ and demographic variables as a mediator of the relationship between mental health and insomnia
Discussion
This study explores the relationship and a mediating mechanism between mental health and insomnia in young soldiers for the first time as far as we know. Especially, mental health literacy, as the mediator evaluate the internal mechanism by cognitive model of insomnia, which provides a new perspective for theoretical guidance to manage insomnia in young soldiers.
Analysis of factors influencing insomnia in young soldiers
This study displayed the possible main influencing factors of insomnia in young soldiers are drinking and sedentary habits, mean frequency of weekly late nights, mean frequency of weekly movements, suffering from disease, mental health status, mental health awareness, and mental illness identification and coping. Namely, young soldiers with drinking habits, sedentary behavior, frequent late nights, inadequate movements, current diseases, high mental health assessments, low awareness of mental health and insufficient mental illness identification and coping were more likely to experience insomnia.
The habit of alcohol consumption can render individuals more susceptible to insomnia. The results may be related to sleep knowledge shortage, lack of awareness of alcohol for unhealthy sleep, and even drinking for sleep [46–48]. Meanwhile, challenges in falling asleep, staying asleep, and other symptoms of insomnia can exacerbate alcohol misuse and its associated consequences [49]. Hence, it is imperative to provide education and support to individuals with alcohol consumption habits who experience insomnia, encouraging them to address their drinking habits to prevent and manage insomnia effectively, especially in young soldiers. Consistent with previous studies [50–52], the present research found that those with sedentary habits had relatively poorer sleep quality. The reasons for this phenomenon may be as follows: on the one hand, individuals with sedentary habits exhibit low energy consumption and metabolism, and a weak sense of fatigue, which are more likely to cause insomnia problems [50]; on the other hand, LED-backlit displays of mobile phone or computer may cause significant suppression of melatonin, thus affecting the biological clock and possibly resulting in sleep problems [51]. Zhang et al. [52] reported that sleep disorders will increase as sedentary behavior added. Young soldiers exhibiting sedentary behaviors are advised to implement strategies such as setting time reminders, increasing standing and walking activities, and other effective measures to enhance their sleep hygiene behaviors and the cultivation of good sleep quality. The findings from this study suggested that the more often young soldiers stayed up late, the higher their ISI scores. It may be related to the decrease in total sleep duration as the frequency of late nights increases, and the lifestyle of staying up late can result in both mental and physical health issues that negatively affect the sleep quality [53, 54]. The research implied that sticking to a consistent bedtime routine would be effective in preventing insomnia. Further, young soldiers who exercised more often each week were found to be less likely to suffer from insomnia. This could be attributed to the energy expenditure and metabolic exhaustion associated with physical exercise, and regular physical activities promoted relaxation and alleviated stress, thereby enhancing overall emotional well-being and improving sleep quality [55, 56]. Taking individual differences into account, the frequency, duration, and intensity of exercise can be tailored and adjusted based on guidelines and personal circumstances and can be strategically planned to optimize sleep quality [57]. Our findings revealed that illness was a predictor of insomnia in military personnel, which was in line with previous studies [7, 13]. Individuals with medical conditions often experienced physiological discomforts, compounded by the potential side effects of medications, which can significantly affect insomnia. Therefore, it was advisable to provide thorough health education on relevant diseases and encourage those who are suffering from illness to seek timely medical treatment, so as to avoid insomnia caused by disease discomfort.
In our study, young soldiers with higher ISI scores also had higher SHQ-12 scores, and Table 4 displays the largest standardized regression coefficient of GHQ-12. It was ascertained that the mental health status of individuals in this population served as a significant predictor of insomnia. These findings are in alignment with previous research conducted by scholars [17, 20–22]. The challenges inherent in military life may contribute to the psychological stress experienced by soldiers, ultimately impacting their sleep patterns [18, 19]. Factors such as rigid regulations, fluctuating and intense work environments, as well as interpersonal conflicts with superiors and comrades can all potentially lead to disrupted sleep patterns [10, 19]. This requires individuals to possess comprehensive knowledge and skills managing their psychological well-being, thus enhancing sleep quality [21, 58]. Psychological service workers can encourage young soldiers to improve mental health literacy, engaging in self-help and aid others, and further enhancing the effectiveness of mental health promotion as well as insomnia management.
According to Table 2, NMHLQ and its mental health awareness and mental illness recognition and coping dimensions had a significant negative correlation with insomnia. Table 4 further revealed that mental health awareness and mental illness identification and coping were significant influencing factors of insomnia in young soldiers. The reasons for this phenomenon may be related to young soldiers’ heightened awareness of mental health, and increased focus on mental health knowledge and skills learning, which enabled them to recognize common mental health issues affecting insomnia and seek the appropriate solutions in time. Notably, the mental health knowledge dimension and insomnia showed no significant correlation, this probably due to the broad and scattered knowledge of this dimension. Therefore, comprehensive and structured mental health knowledge needed to be intensified, so as to enhance young soldiers’ mental health literacy as well as risk reduction in insomnia.
Mediating effects of mental health literacy between mental health and insomnia
The findings of the mediation analysis unveiled significant overall effects in the pathways from GHQ-12 to NMHLQ-A and from GHQ-12 to NMHLQ-I to ISI, supporting the hypothesis regarding the mediating influence of mental health literacy in the association between mental health and insomnia. These findings suggest that mental health can forecast insomnia in young soldiers through the mediation role of mental health literacy. Mental health literacy is identified as an intervenable, easily accessible, and efficient resource for addressing mental health challenges; therefore, enhancing mental health awareness and strengthening the ability to recognize and manage mental illnesses can effectively safeguard and manage the mental health of young soldiers, ultimately contributing to the improvement of sleep quality [23, 24].
As hypothesized, the mediating effects of mental health literacy on the relationship between mental health and insomnia remained statistically significant both before and after controlling for relevant variables. Despite the relatively small direct effects of the NMHLQ-A and NMHLQ-I, interventions aimed at improving mental health literacy at the individual level may potentially lead to substantial cumulative effects at the population level. Thus, even small improvements in young soldiers’ mental health literacy may contribute to significant positive outcomes on a larger scale. Moreover, the general data with five control variables such as drinking habits, sedentary behavior, mean frequency of weekly late nights, mean frequency of weekly movements, and suffering from illness exhibited both direct and indirect mediating effects in the model 2. Previous research had validated that boosting mental health literacy could more likely promote healthy lifestyle among individuals [29]. Lifestyle factors including drinking habits, sedentary behavior, mean frequency of weekly late nights, mean frequency of weekly movements, all four influencing factors of insomnia among young soldiers, further underscored the role of mental health literacy in preventive treatment of insomnia in this population.
Overall, the findings supported the hypothesis that young soldiers’ mental health literacy can mediate the relationship between mental health and insomnia, underscore the importance to enhance their mental health awareness and improve their ability to identify and cope with mental illnesses, and provide a perspective for the intervention of factors affecting insomnia in young soldiers from mental health literacy.
Conclusion
The study findings reveal the significant role of mental health literacy in mediating the relationship between mental health and insomnia among young soldiers. To effectively address insomnia in this demographic, interventions should prioritize individuals with high levels of alcohol consumption, sedentary behavior, frequent late nights, lack of physical activity, existing illnesses, elevated mental health assessments, and low scores in mental health literacy. Mental health professionals should recognize the impact of mental health literacy in the prevention of insomnia from a clinical perspective and should actively implement feasible and effective approaches, such as psychological counselling, psychoeducational courses, and mental wellness training to enhance mental health awareness, facilitate early identification and management of mental illness, and ultimately promote healthy sleep patterns.
Strengths and limitations
This study represents the inaugural investigation into the mental health literacy of young soldiers, elucidating the mediating function of mental health literacy in the association between mental health and insomnia, and yielding a novel approach to intervention for insomnia within this demographic. However, the study is subject to several limitations. Primarily, being a cross-sectional survey, a definitive causal relationship between variables could not be ascertained. A longitudinal study is imperative for a more comprehensive understanding of the role of mental health literacy in mental health and insomnia progression over time. Moreover, due to the survey’s limited scope, which was exclusively confined to young soldiers from a specific locality with an uneven gender distribution, there is a critical exigency for broader representation within the study population. Lastly, the current study relied on self-report questionnaires to ascertain insomnia status, as opposed to structured clinical interviews conducted by a professional sleep clinician, which can only discern symptoms of insomnia rather than offer a formal diagnosis. Consequently, future research endeavors should encompass individuals diagnosed with insomnia and incorporate both subjective and objective assessment methodologies to augment data precision.
Acknowledgements
The authors gratefully acknowledge all the young soldiers who participated in this study.
Abbreviations
- ISI
Insomnia Severity Index
- GHQ-12
The 12-Item General Health Questionnaire
- NMHLQ
National mental health literacy questionnaire
- NMHLQ-A
Mental health awareness of national mental health literacy questionnaire
- NMHLQ-I
Identification and response to mental illness of national mental health literacy questionnaire
Author contributions
MW, HN, CN, BW and SX designed the study; MW and BW involved in data collection and supervision; MW and HN conducted statistical analysis; MW, HN and CN contributed to the writing of the manuscript; PS, XL and MH provided English proofreading. All authors reviewed the final manuscript.
Funding
This study was supported by grants from Medical Science and Technology Research Project (2022ZZXM025).
Data availability
The datasets used and/or analyzed during the current study available from the corresponding author on reasonable request.
Declarations
Ethics approval and consent to participate
This study was approved by the Ethics Committee of Chinese PLA No.991 Hospital (991YJ-202206), and informed consent was obtained from all the subjects involved in the study.
Consent for publication
Not applicable.
Competing interests
The authors declare no competing interests.
Footnotes
Publisher’s note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Contributor Information
Song Xu, Email: 99043339@qq.com.
Bin Wang, Email: wangbinfmmu@163.com.
Chunping Ni, Email: pingchunni@163.com.
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Data Availability Statement
The datasets used and/or analyzed during the current study available from the corresponding author on reasonable request.