Abstract
Stress among adolescents is a widely discussed topic. This study examined stress levels, stress-related factors, and the possible correlation between stress and depression in adolescents at high schools in Thailand. The survey measuring stress (T-PSS-10) and depression (PHQ-9) was conducted on 15- to 19-year-olds in three public urban schools (n = 168, response rate 90%). The data were analysed with descriptive statistics followed by the analysis of the background factors and their associations with adolescent stress levels using χ 2 tests, or Pearson’s correlation coefficient, while the mean differences between groups were tested with a T-test or analysis of variance. Adolescent stress levels ranged from 6 to 34 points, 17 being the most typical score (mean 15.95, SD 4.95, n = 164); the higher the score, the more the respondents perceived their lives to be stressful. There were no significant differences in stress levels among adolescents relating to age, gender, regular school attendance or which school attended. However, adolescents’ high stress levels were associated with having a high number of depressive symptoms (r = 0.69, p = < 0.001). Effective mechanisms and more studies need to be carried out in the school environment to monitor, identify and support adolescents’ health and well-being.
Introduction
Well-being and mental health among adolescents constitute a global concern (WHO, 2009). The adolescent years include developmental, environmental and contextual stressors (Garcia, 2010), adolescents may experience stress when something is difficult or painful, or if they do not have the resources needed to cope. Overloading with stress may lead to anxiety, withdrawal, aggression, or physical illness (AACAP, 2012). Stress is related to depression (Stroud et al., 2008) and environmental and genetic factors can lead to stress (Casey et al., 2010). Stress in adolescents is also associated with suicide attempts (Sandin et al., 1998). Supportive interventions, for example, cognitive behavioural therapy, should therefore be used actively to help adolescents deal with difficulties in their daily lives and prevent mental health problems (Corrieri et al., 2014).
According to Suldo et al. (2009), students in some high school programmes experience more stress related to academic demands than the more typical adolescent stressors (e.g. conflicts with family and peers). Students in higher grades who have taken a student loan have been found to feel more physical/mental, school-related, and emotional stress than students in lower grades who have not taken a student loan (Cheng, 2009), although contradictory results have also been found (Chernoma and Shapiro, 2013). Stress may result from taking on too many activities or having too high expectations, and it may include negative thoughts and feelings about oneself (AACAP, 2012). Taiwanese research suggests that male students feel family-related stress more strongly than female students do (Cheng, 2009).
Stress is a widely discussed topic, even though stress-related factors and the impact of stress on adolescents’ mental well-being is less often studied. Stress from romantic breakups is associated with mental health and substance use, and various sources of personal stress has been linked to depression symptoms (Low et al., 2012). Stress levels have been found to significantly moderate the relationship between depression and negative life events. For those with a low perceived stress level, negative life changes have only a minimal impact on depression level (Kuiper et al., 1986). Higher depression scores are associated with ineffective coping, higher pre-faculty stress and current faculty stress, and those who cannot cope effectively often have higher stress scores (Chernoma and Shapiro, 2013). Strategies attempting to damage, disrupt, and dissolve a stressful relationship are associated with high levels of depressive symptoms (Kato, 2014).
Identifying factors associated with adolescent mental health is important because problems tend to continue throughout life, if they are left untreated (Casey et al., 2010). Schools are places where stress symptoms should be identified and preventive interventions should be initiated (Powers et al., 2010). However, there is still a lack of knowledge regarding the association between adolescents’ stress levels and depressive symptoms in developing countries. Thus, we aim to examine stress levels among adolescents, the factors associated with adolescent stress, and the possible correlation between stress and depression in adolescents at high schools in Thailand. The study is part of the EduMental project (1547/31/2012), intended to support adolescents’ self-management abilities. Baseline data are reported here. As far as we are aware, this is the first study conducted in Southern Thailand concerning adolescents’ stress and mental well-being in the school environment. Previous studies have been conducted in Tsunami-affected areas and have related to post-traumatic stress (Sitdhiraksa et al., 2014).
Methods
Study design
A descriptive survey with convenience sampling.
Setting
Three urban public high schools located in Southern Thailand in a province with 1,394,915 inhabitants (45 public high schools; 18,571 children). In these three schools, there were altogether 4,894 adolescents from 15 to 18 years old. Education in Thailand is provided mainly by the Thai government through its Ministry of Education (MOE). Free basic 12-year education is guaranteed by the constitution, and a minimum of nine years of school attendance is compulsory (MOE, 2008).
Recruitment and population
To obtain homogenous data regarding school size, type (public schools), location (city) and curricula, the purposive convenience sampling method was used, based on the previous knowledge of the researcher on our team from Thailand. The schools and study systems vary greatly in Thailand depending on the geographic area, and therefore the schools were recruited based on information gathered from available sources.
Three school principals were contacted, and a general idea of the study was introduced to them. An information letter about the study and its aims was sent to the principals. A meeting with the researcher was organized at each school to offer more detailed information. The three school principals agreed that their schools would participate in the study and proceeded to inform each respective school staff about it.
The study population was formed by school-aged adolescents from 15 to 19 years old. Certain procedures apply to ethical approaches among children and adolescents in international settings (Schenk and Williamson, 2005). Local qualified authorities from the Faculty of Humanities and Social Sciences at Prince of Songkla University in Thailand were consulted about the proposal and its attachments, and ethical assessment was approved in Finland. According to medical research on children, adolescents who are 15 years or older should be given a possibility to provide individual written consent for participation (Lötjönen et al., 2000). In each school, a few classes were selected using the purposive sampling method with the help of the school principal, guidance teachers and a school nurse, according to the availability of the students at the time of data collection. Besides age, other inclusion criteria were ability to read, write and speak Thai, voluntary participation and ability to give informed written consent.
Instruments
The data were collected using a survey. First, adolescent stress was measured by the Perceived Stress Scale (PSS) by Cohen et al. (1983). It assesses the degree to which people perceive their lives as stressful. It has been designed for use with community samples with a minimum of junior high school education. Subjects indicate how often they have found their lives unpredictable, uncontrollable, and overloaded in the last month. A five-point scale is used (0 = Never, 4 = Very often), and the total score ranges between 0 and 40. The PSS has adequate internal and test–retest reliability, and it is correlated with a range of self-reporting and behavioural criteria (Cohen et al., 1983). Cronbach’s α of the PSS-10 was evaluated at >.70, and its test–retest reliability met the criterion of >.70 (Lee, 2012). The Thai version, T-PSS-10, was used with the permission of the Thai authors. Its psychometric properties have been examined with a clinical and non-clinical sample, and it has been demonstrated to be a reliable and valid instrument within the Thai culture (Wongpakaran and Wongpakaran, 2010).
Second, the Quick Depression Assessment (PHQ-9) was used to measure signs of depression (APA, 2014). It includes nine items where respondents indicate on a four-point scale how often they have been bothered by any of the problems over the last two weeks (0 = Not at all; 3 = Nearly every day). Based on the individual items, a total score is formed; the higher the score, the more severe the depression symptoms (range 0–27). According to Kroenke et al. (2001), the instrument has been evaluated to be reliable. Its diagnostic validity was established in studies involving primary care and obstetrics clinics. PHQ scores ≥ 10 had a sensitivity of 88% and a specificity of 88% for major depression. The Thai version of the instrument has satisfactory internal consistency (Cronbach’s α = 0.79) and high specificity (0.98) (Lotrakul et al., 2008). It was used with the permission of the copyright holder.
Background information of the adolescents was collected: age, gender, information on regular school attendance (yes, no), school.
Data collection
An information session was organized to invite adolescents in each of the three schools to participate in the study. All 188 adolescents received oral and written information about the study. They were informed that their participation is voluntary, confidential and that they could withdraw from the study at any time without any consequences. The students received written information to read, consent forms to sign and a parental information sheet to take home.
After that, they completed the questionnaires (15–30 minutes), had an opportunity to ask questions and returned the questionnaires to the researchers. Nine students did not complete consent forms and the questionnaires, and seven additional students were recruited. However, out of those 186 students, 90% (n = 168) ultimately completed the questionnaires.
Data analysis
For the PSS-10 scale, four negative scores were recoded. The items were reversed as follows: 0 = Never to 4 = Very often; 1 = Almost never to 3 = Fairly often, and vice versa. The items in the instrument were to be scored in the reverse direction. The total score was then formed by calculating a value for each of the 10 questions. Due to the small sample size in some subcategories, background information was recoded (age groups 15, 16, 17 years old or older). Descriptive statistics were analysed (frequencies, percentages, mean, SD).
For the PHQ-9 scale, a total score was formed by summing the values of all items (APA, 2014). Differences between adolescents’ stress scores related to their background information and depression scores were tested with χ 2 in case of categorical groups. The mean differences between groups were tested with a T-test (two comparative groups) or with ANOVA (three comparative groups).
Correlations between numeric variables were analysed with Pearson’s correlation coefficient test.
Ethics
Ethical guidelines (WMA Declaration of Helsinki, 2013) were followed throughout the study. Qualified authorities at the local university and the principals evaluated whether the study fulfilled the ethical requirements. The principals were informed about the procedures for data collection, were aware that the results would eventually be provided to the school and granted permission to conduct the study. Ethical assessment was approved (17/2016) by the ethics committee of the University of Turku. The procedure conforms to standards currently applied in Thailand.
Parents or guardians were informed through information sheets provided, while teachers and students were also informed about the study content orally. Adolescents’ participation was based on their own free will. In case of refusal, they were able to return an empty instrument without anyone knowing it. The data were transferred, analysed and reported in a way that individual respondents could not be identified.
Results
Description of the participants
Of the participants (n = 166), half (51%) were 16 years old, less than one-third (28%) were 15 years old, and one-fifth were 17 years old or older (21%). The mean age of the students was 16 (mean 15.94, SD 0.74). About two-thirds were females (68%, n = 167) and 98% had attended school regularly. The three schools were represented by the participants in the study (n = 168) evenly: 35% of the participants (n = 58) attended school A, 32% (n = 54) attended school B, and 33% (n = 56) attended school C.
Perceived stress among adolescents
The adolescents’ stress levels ranged from 6 to 34 points. The most common score was 17 (19 students); the higher the score, the more the respondents perceived their lives to be stressful (see Table 1). The mean score of students’ stress levels was 15.95 (SD 4.95, n = 164).
Adolescents’ stress levels (n = 164).
Factors associated with adolescents’ stress levels
We looked for a relationship between stress factors and participants’ backgrounds. For the mean comparisons between groups, there were no significant differences in stress level by age, gender, regularity of school attendance or which school was attended.
Correlation of stress levels and depressive symptoms
The possible correlation of adolescents’ stress levels (T-PSS-10; range 6-34, mean 15.95, SD 4.95, n = 164) and depressive symptom scores (PHQ-9; range 0-22 points, mean 7.90, SD 3.95, n = 159) was analysed with Pearson correlation coefficient. The analysis showed a strong statistically significant and positive correlation between adolescents’ stress levels and depressive symptoms: the more stress adolescents perceived, the more depressive symptoms they reported (r = 0.69, p = < 0.001).
Discussion
Our study examined adolescents’ stress levels, stress-related factors, and the possible correlation between perceived stress and depression in adolescents at high schools in southern Thailand, a politically unstable area. Our study showed that if adolescents are stressed, they also have more depressive symptoms. The result may be due to their living conditions or other areas of life.
In contrast to earlier studies, no group difference was found in our study regarding age (Chernoma and Shapiro, 2013), gender, regularity of school attendance or schools, for example, schoolwork (Low et al., 2012). However, there was a strong positive and statistically significant correlation between adolescents’ stress and symptoms of depression (r = 0.69, p = < 0.001). Adolescents also reported a variety of problems, concerns, and feelings in a digital support system developed for their use (Välimäki et al., 2016). This supports the earlier findings demonstrating a relationship between stress and depression (Kuiper et al., 1986; Low et al., 2012; Stroud et al., 2008). Stress levels were higher than in the data previously collected in Thailand: adolescents’ mean stress level score (15.95, SD 4.95) was higher than in a study involving medical students (13.53, SD 4.56) and research involving patients from two hospitals in Northern Thailand (13.99, SD 4.27) (Wongpakaran and Wongpakaran, 2010) but lower than that reported in a global study by the PSS-10 developers (Cohen et al., 1983).
It is possible to identify factors related to adolescents’ health and well-being. It has been estimated that each year 38% of the EU population suffers from a mental disorder (Wittchen et al., 2011), and worldwide, the main cause of years lost because of a disability for 10- to 24-year-olds has been neuropsychiatric disorders (Gore et al., 2011). In Thailand, the prevalence of high levels of depressive symptoms is around 20% (Charoensuk, 2007). Public health and well-being among adolescents should be the focus of school-based mental health prevention programmes. To the best of the authors’ knowledge, the present study is one of the first studies conducted and published for an international audience that focuses on Thai school life, where the association of adolescents’ stress levels and depression has been measured in a school environment. The study can serve as an important reference for Asian societies and other countries to look to when school and academic success is seen as essential for the future. It is important to identify factors associated with adolescent health and well-being as early as possible and to support them to avoid detrimental outcomes such as overly demanding academic competition, suicides (Nguyen et al., 2013; Snowdon et al., 2017), and self-injurious behaviour (Tresno et al., 2012). The association between suicide and stress in school life should be more carefully investigated. Stress may be one sign that should be looked for by school teachers, parents and adolescents and raise alarm if noticed. This could later help adolescents to cope with potentially overwhelming academic requirements (Suldo et al., 2009) or other stressful life events.
Limitations
First, the school recruitment was not random. The study data may be biased towards more motivated schools, which have already taken adolescents’ well-being seriously and are willing to develop it further. Second, the sample size is relatively small. Third, the area where the study was conducted is unique due to its local situation and political instability, which may have had impact on adolescents’ well-being in terms of depression, academic performance and social relationships (Sakhelashvili et al., 2016). This also inhibits generalizability in Thailand. In addition, only urban schools participated, possibly causing the results to be applicable only in similar areas. Fourth, some students showed signs of stress, but it was unclear if stress was due to depression or vice versa.
Data collection using different methods, such as interviews, could have strengthened the results. Further studies are therefore needed based on rigour research methods, larger sample sizes, and more sophisticated statistical analysis. Intervention studies with randomization are needed to test whether any preventive interventions could be useful in decreasing stress among adolescents and increasing their mental well-being. The study is still valuable to the topic because, as the systematic review showed, RCTs with at least 100 participants focusing on school-based prevention interventions on depression and anxiety disorders have not been realized in Thailand, nor in several other countries (Corrieri et al., 2014). However, because adolescent mental health is a highly sensitive research topic, conducting a wide study requires the appropriate support mechanism to identify, maintain and safeguard adolescents’ mental well-being during and after the study. This support in the school environment can minimize adverse events and make sure contact persons are available and known in case the adolescents have worries or concerns at any stage of the study.
Conclusions
Despite the limitations, it is possible to identify students who may need psychoeducation support to reduce their stress levels at school, even in Thai and other Asian cultures where emotional self-control may be expected (Park and Kim, 2008) and individuals demonstrate strength to tolerate stress. Effective mechanisms to identify, monitor and support students’ well-being in their daily lives are needed. Healthcare workers, such as nurses working at schools or in the community, have an important role. Innovative psychoeducation interventions should be developed and tested in school environments to prevent and manage stressful situations for adolescents. This age group should be given supportive coping strategies to prevent, with the help of skillful personnel, any detrimental implications of long-term stressful life situations and depressive symptoms.
It is possible to identify students at school who may need support to reduce their stress levels. From the teachers’ and organizational perspectives, the study expands the opportunities to use instruments when assessing adolescent well-being in the school environment and to consider interventions to support the positive coping skills of adolescents in need of help.
Footnotes
Declaration of conflicting interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: We acknowledge Tekes – the Finnish Funding Agency for Innovation and University of Turku of their financial support.