This study used a descriptive correlation design and structured questionnaire to explore the relationship between mental health literacy level and perceived social support and subjective well-being of middle-aged and young urban and rural residents.

In January–February 2022, 620 people from Henan, Jiangsu and Zhejiang provinces of China were selected for the survey using convenience sampling. Inclusion criteria were as follows: (1) 18–60 years old; (2) free from any psychiatric disorders; (3) reading comprehension literacy skills; (4) able to use smartphones for simple operations; (5) informed consent. Exclusion criteria were residents who frequently switch between urban and rural residences.

To facilitate sample collection, we selected residents from three provinces in central and eastern China by convenience sampling, which can well represent the regions with relatively concentrated population in China. This study used the online “Questionnaire STAR” method, where all questionnaires were completed anonymously. The researcher set up the questionnaire on “Questionnaire STAR”, created a QR code and a link to the website, and distributed the survey to the residents, who used their mobile phones and other devices to answer the questions online. To avoid missing questions, the researcher set each item as a compulsory question to ensure the quality of the questionnaire. The Mental Health Literacy scale (MHL) includes 22 entries, and we calculated a sample size of 660 based on a 25:1 ratio sample size, taking into account a 20% missing visit rate. Ultimately, we deleted 40 invalid questionnaires, and a total of 620 questionnaires were retained for analysis for a valid return rate of 94.0%.

SPSS 25.0 and AMOS 22.0 statistical software were used for data processing. The statistical data were described by percentages; the measurement data were normally distributed and described by means ± standard deviations (x ± s); independent samples t test and one-way ANOVA were used to analyze the differences between urban and rural middle-aged youth. Pearson correlation analysis was used to explore the relationship between mental health literacy, perceived social support and subjective well-being of middle-aged youth, and structural equation modeling was used to explore the role of perceived social support. A structural equation model was used to explore the mediating role of perceived social support in the relationship between mental health literacy and subjective well-being [24]. The bias-corrected bootstrap method was used to test the significance of the mediating effect.

The Harman single-factor test was used to statistically control for common method biases. The results showed that the variance explained by the first factor was 37.542% (<40%). Therefore, there was no serious common methodological bias in this study.

Young and middle-aged residents differed in their mental health literacy, social support, and subjective well-being scores by urban vs. rural residence (P < 0.001). See Table 1 for details.

Table 1 shows that there are differences in mental health literacy scores between young and middle-aged residents in rural and urban areas, and a comparative analysis using different demographic variables as independent variables and mental health literacy scores of young and middle-aged residents in rural areas and urban areas as dependent variables shows that among young and middle-aged residents in rural areas, there are statistically significant differences in mental health literacy by gender, age, education, marital status, monthly income, and interpersonal relationships (P < 0.001). Among young and middle-aged urban residents, there were statistically significant differences in mental health literacy in terms of gender, age, education level, marital status, monthly income, and interpersonal relationships (P < 0.001). See Table 2 for details.

The total mental health literacy score and each dimension were positively correlated with the total PSSS score and each dimension, the total mental health literacy score and each dimension were positively correlated with the total SWB score and each dimension, and the total PSSS score and each dimension were positively correlated with the total SWB score and each dimension among young and middle-aged residents in rural and urban areas (P < 0.01) (Table 3).

Using the total mental health literacy score as the dependent variable, the factors that were statistically significant after univariate analysis of different demographic variables of rural and urban young and middle-aged residents were included as independent variables in the regression equation, and multiple linear regression analysis was conducted. The results showed that gender, age, education level and interpersonal relationships were the influencing factors of the mental health literacy of rural residents; education level, monthly income and interpersonal relationships were the influencing factors of mental health. The details are shown in Tables 4 and 5.

To test the mediating role of perceived social support in the relationship between residents’ mental health literacy and subjective well-being, the hypothetical model was tested using structural equation modelling, and the model fit indices are shown in Table 6.

The bias-corrected bootstrap method (5,000 draws) was used to test the significance of the mediating effects of the model. The direct effect of mental health literacy, perceived social support and subjective well-being for rural middle-aged youth c’ = 0.16 (P < 0.05), the mediating effect value a * b = 0.63 (P < 0.01), 95% confidence interval (0.502–0.732) excluding 0 and (P < 0.01), direct effect c’ = 260 (P > 0.05), mediated effect value a * b = 0.74 (P < 0. 01), 95% confidence interval (0.354–0.591) and (P < 0.01), indicating that the mediating effect was statistically significant, with middle-aged and young rural residents’ perceived social support partially mediating the effect between mental health literacy and subjective well-being, with an effect ratio of 0.80, middle-aged and young urban residents’ perceived social support partially mediating the effect between mental health literacy and subjective well-being, with an effect ratio of 0.74, and mental health literacy positively predicted perceived social support (rural β = 0.896, urban β = 0.823, P < 0.01); perceived social support positively predicted subjective well-being (rural β = 0.706, urban β = 0.895, P < 0.01). The specific structural equation models are shown in Figs. 2 and 3.

A comparative analysis shows that urban residents have higher mental health literacy scores than rural residents, and there is a correlation between mental health literacy and occupation and education level [25]. Urban areas have more comprehensive and advanced medical and internet facilities than rural areas, so urban residents have more access to mental health knowledge and this may account for their higher mental health literacy scores. In contrast, rural areas are more populated by farmers, whose knowledge of mental health is weaker [26]. Therefore, the popularity of mental health knowledge in rural areas should be increased to increase farmers’ willingness to seek help and further improve their mental health literacy level.

The results of the multiple regression analysis showed that the mental health literacy scores of rural middle-aged youths were statistically significant in terms of gender, age, literacy and interpersonal relationships, while the mental health literacy scores of urban middle-aged youths were statistically significant in terms of literacy, monthly income and interpersonal relationships. The mental health literacy scores of both rural and urban young people were significant in terms of literacy and interpersonal relationships, and those with higher literacy levels had higher levels of mental health literacy: this may be because with the continuous improvement in the economic and educational levels of society, young people are generally more educated and have more opportunities to receive education than in the past, thus becoming more knowledgeable about mental health. Further, the higher the literacy level is, the greater the education and awareness of the importance of mental health and the more positive they are about seeking professional help [27]. Research suggests that better interpersonal relationships are associated with higher levels of mental health literacy, which may be related to higher levels of social support positively associated with mental health literacy [28].

Further comparisons revealed that the differences in gender and age were more pronounced among rural residents than urban residents. The gender difference from Lee et al.’ study [29] may be because the social status of Chinese women has increased significantly compared to the past. Because urban women are now able to work and socialize in the same way as men, the difference in mental health literacy levels is not significant. However, due to the limited economic development in rural areas, the number of available jobs is insufficient, and the social custom of “men taking care of the outside world and women taking care of the inside” is often followed in rural areas. So, compared to urban women, rural women are more likely to stay at home and have less contact with the outside world and are therefore more prone to mental health problems and have lower mental health literacy than men [30]. In terms of age, as rural residents grow older, their ability to work decreases, and their ability to care for themselves decreases to varying degrees, requiring the care of their children. In contrast, urban residents have more social security and a higher rate of medical insurance reimbursement than their rural counterparts. In addition, in cities where parents and children usually live together, urban residents receive more social support and care, thus improving their mental health literacy levels. In addition, the monthly income of urban residents is significantly higher than that of rural residents. In rural areas, the income level is not very different, as most of the residents are mainly engaged in agriculture, while in cities, the difference in income is greater due to the difference in occupation, and the residents have a different sense of access, which leads to a different level of mental health literacy. In summary, residents in different places of residence are affected differently, and it is necessary for the relevant government departments to develop mental health first aid for different groups of people [31].

The results of this study show that mental health literacy is closely related to both perceived social support and subjective well-being among young and middle-aged rural and urban residents, and comparing the R-values of the two groups intuitively reveals that rural residents score higher than urban residents. The positive correlation between mental health literacy and subjective well-being among urban and rural residents is in line with the findings of Liu et al. [32] on the elderly population. The study suggests that when individuals have positive attitudes and behaviors in the face of their illness, their satisfaction with quality of life improves and that positive mental health literacy improves an individual’s subjective well-being [33,34]. Mental health literacy is positively correlated with perceived social support, which is a common mediating variable in psychological research and plays an important protective role for individuals’ mental health; studies have found that individuals with lower perceived social support are more likely to experience physical and psychological symptoms such as anxiety and depression and thus have better levels of mental health literacy [35,36]. Although this survey has had a stimulating effect on mental health literacy, the results suggest that there is still a need for a range of activities to improve mental health literacy in the population [37]. At the same time, the positive correlation between perceived social support and subjective well-being is consistent with the findings of Liu et al. [38] study on university students, which found that young and middle-aged people who obtain support from family, friends and other social sources have a greater sense of well-being, and individuals with higher perceived social support are usually able to navigate life more positively, set clear goals, and enhance their subjective well-being. High levels of social support play an important role in maintaining their psychological well-being, enhancing their professional identity and sense of professional fulfilment, and increasing their level of well-being.

This study further investigated the mediating role of perceived social support in the relationship between mental health literacy and the subjective well-being of young and middle-aged urban and rural residents and found that perceived social support partially mediated the relationship. This suggests that mental health literacy not only directly influences the subjective well-being of young and middle-aged urban and rural residents but also indirectly influences subjective well-being through perceived social support, which is an ability to obtain support from the outside world and can contribute to the growth of individual mental health and well-being [39]. Comparing the rural and urban structural equation models, we found that the total effect of mental health literacy on subjective well-being was intuitively 0.80 for rural residents compared to 0.74 for urban residents, probably because rural residents, compared to urban residents, have a greater need to translate social support into a positive state in response to various events, thus being able to better predict the level of well-being. Thus, residents with a high level of mental health literacy will have a more positive mindset, and this positive mindset will help individuals feel more respected, supported and understood in social interactions, giving them a higher level of social support, which will expand their individual and social resources increase their level of well-being [40]. The survey found that improving the mental health literacy of farmers and parents helped them better seek social help [41,42], When individuals have adequate social support for their needs, their subjective well-being is enhanced. The current level of mental health literacy among Chinese residents is not high, and its direct prediction of well-being is not significant. The prediction of mental health literacy on subjective well-being will be greatly enhanced with the mediation of comprehending social support, which suggests that researchers should focus on the role of social support on individuals’ mental health literacy to improve their subjective well-being.

This study mainly selects urban and rural residents in three regions of China, and the sample size is not large enough. The differences between urban and rural residents in mental health literacy and perceived social support in mental health literacy and subjective well-being need to be further explored and analyzed by enlarging the sample size. In addition, the populations selected in this study all live on the plains, and future studies can include residents living in mountainous areas to explore whether there are corresponding differences.