High Prevalence of Depression, Anxiety and Stress Among Secondary School Students During COVID-19 Lockdown and Social Distancing and Its Associated Factors: An Online Cross-Sectional Survey


 Background: Stressors introduced to adolescents by COVID-19 social distancing measures may cause mental health problems to (re)surface. We studied depression, anxiety and stress among adolescents experiencing lockdown. Methods: From May-June 2020, secondary school students were enrolled in an online cross-sectional survey through social media. We assessed presence and severity of depression (PHQ-9), anxiety (GAD-7) and stress (PSS-10) in the last month, demographics, degree of social distancing, and other associated issues.Results: Of 392 respondents (56.4% male, 43.1% female), mostly from Thailand (59.2%) and UK (26.5%). We identified depressive symptoms in 58.7%, anxiety in 40.3% and high levels of stress in 9.7%. We found, by multivariate analysis, significant associations between being female and depression and anxiety, being in late secondary school years and depression, and changes in patterns of substance use and anxiety and stress.Conclusions: We propose that girl-centred mental health support platforms should be readily available and tailored to fit specific countries’ contexts. Schools must closely monitor and act upon any concerns which arise from their students and must also monitor mental health wellbeing as changes in academic routine due to COVID-19 could be drastic for some. Harm reduction services must adapt and utilise innovative telemedicine interventions, tailored towards adolescent users.

In general, lockdown and its element of social and physical distancing elicits a toll on mental health; the World Health Organization (WHO) a rms that social dysfunction will result in elevated prevalence of psychiatric illnesses (5). Hawryluck et al. showed that persons quarantined in Toronto, Canada, during the 2004 SARS outbreak displayed a high prevalence of depression (6). Jeong et al. reported higher rates of anxiety among individuals during their isolation period compared to 4-6 months after isolation due to the 2015 Middle East Respiratory Syndrome (MERS) outbreak in Korea (7). More recently, Huang and Zhao have identi ed a "major mental health burden" on the Chinese public amid the COVID-19 outbreak (8).
Since the pandemic's inception, there have been some studies conducted which have begun to assess how COVID-19 social distancing and isolation can lead to adverse mental health effects (8,9) and further consequences such as substance abuse (10)(11)(12). However, evidence and data on how large-scale public health measures affect adolescent mental health outcomes is scarce (13). Xie et al. report higher prevalence of depression and anxiety among primary school children in home con nement during a Chinese nationwide school closure (14). Zhou et al. describe similar ndings with Chinese high school students (15). Despite this, there have not been any studies examining the disparities between mental health impact from country to country, and certain associated factors such as adolescent substance use.
Thailand and the UK are two countries which, despite similar population sizes, have experienced very different trajectories regarding COVID-19 outbreak. Thailand reported the rst case of COVID-19 outside of China on 13 January 2020 (16), with the virus reaching the UK shortly after later in the month (17). In response, social distancing measures were implemented by both governments. On 21 March 2020, the Bangkok Metropolitan Administration authority declared widespread shutdown of various businesses. A national public state of emergency was declared on 25 March, with a general lockdown and social distancing requirements instituted on 26 March. In the UK, governmental response was initially in the form of guidance. As the situation escalated, legislation was enacted in the form of statutory instruments, which included implementing closures of schools, businesses and non-essential services, restrictions on movement and gatherings, and enforcement. A stay-at-home order came into effect on 26 March. Despite taking action at around similar times, the two countries currently nd themselves in dissimilar situations. Since then, as of 7 September 2020, Thailand has had 3,445 COVID-19 cases, compared to 347,152 cases in the UK. Their death rates per million people differ substantially: 0.8 for Thailand, but 611 for the UK (making it the sixth-highest death rate per million people globally among major countries) (18). Thus, it would be interesting to examine the differences in adolescent mental health amid a worldwide pandemic, but in differing COVID-19 situations.
We therefore aimed to pilot assess the impact of social distancing on the mental health of secondary school students in Thailand and UK, including the degree and prevalence of depression, anxiety and stress, as well as how lockdown-speci c associated factors can impact this. However, there will be no geographical boundaries due to the use of online survey.

Study participants
We advertised a study survey link launched to students in Thailand and UK via snowball sampling on social media popular with youths, including Instagram, Snapchat, WhatsApp and LINE. The location of study had no physical space, and participants instead accessed the digital platform of Google Forms on an online system. Further distribution of the survey link was done by earlier participants via instant messaging as well as 'story reposts'. In order to answer the questions, participants had to be enrolled in school from Year 8 (Grade 7) to Year 13 (Grade 12) and be able to understand, read and write (type) English.
Consent by action was obtained via a digitalised consent form, explaining the objectives and contents of the survey as well as potential risks and intended bene ts. We designed the online survey layout such that no study procedures would occur prior to the participant giving informed consent. Despite most participants being under 18, parental consent was waived due to the anonymous nature of the survey.
The study was approved by the Institutional Review Board of the Faculty of Medicine, Chulalongkorn University.

Study procedures
The cross-sectional survey on mental health was created using the online service Google Forms, and participants could access the survey and answer questions on it. The survey was open to responses from May to June 2020. Content included diagnostic instruments used to assess symptoms of depression, anxiety and stress, but also questions designed to identify general demographics, degree of social distancing and other associated factors. Open-ended questions were also implemented in order to allow participants to expand on certain issues or topics.
Prior to o cial deployment, 10 individuals were selected to test the questionnaire. These individuals were speci cally selected so that feedback obtained later on was based on demographically diverse opinions.

Study measurements -Depression
The 9-item Patient Health Questionnaire-9 (PHQ-9) was used to assess depressive symptoms. PHQ-9 forms the depression module of the Patient Health Questionnaire (PHQ), which is the self-administered version of the PRIME-MD diagnostic tool developed by P zer. It has been validated for adolescent use (19). Participants scored their frequency of experience with each of the nine DSM-IV criteria over the last two weeks (e.g. poor appetite or overeating, feeling tired or having little energy, with their 4-point Likertscale ratings representing frequencies ('0' is not at all, '1' is several days, '2' is more than half the days, '3' is nearly every day). Scores were then totaled, with cut off points correlating to level of perceived depression (0-4 = none, 5-9 = mild, 10-14 = moderate, 15-19 = moderately severe, 20-27 = severe).
Participants who scored above 4 were considered to exhibit depressive symptoms.

-Anxiety
The 7-item Generalized Anxiety Disorder Scale (GAD-7) was used to assess anxiety symptoms. GAD-7 forms the anxiety module of the PHQ. The GAD-7 items correspond with DSM-IV criteria and use the same 4-point Likert-scale ratings as PHQ-9 to assess frequency of experience with criteria over the last two weeks, and thus presence and severity of anxiety. Participants rated each item, and scores were then totaled. Cut-off points correlating to level of perceived anxiety were: 0-4 = none, 5-9 = mild, 10-14 = moderate, 15-21 = severe. Participants who scored above 4 were considered to exhibit anxiety symptoms.

-General information
Participants inputted general demographical information such as gender, age, school year, country currently residing in and country studying in. We also asked questions relevant to their lockdown experience, regarding topics such as substance use (previous and current uses as well as changes in patterns of use) and issues with online learning and exam cancellations (experience, and whether this was problematic). Participants were also able to report any previously diagnosed mental illnesses, and whether they experienced any change in this during lockdown.
Demographical and lockdown-related variables were compared between participants of differing levels of depression (Present/Not present), anxiety (Present/Not present) and perceived stress ('low'/'moderate to high'). Chi-square test was used for categorical variables, while Student's t-test was used for continuous variables. Logistic (nominal) regression analysis was used to evaluate signi cant associations between predictive variables and presence of depression, anxiety and severity of perceived stress. Odds ratios (ORs) of predictive factors were reported, together with 95% con dence intervals (CIs). Statistical signi cance was set at p < 0.05. SPSS software (version 22) was used to perform statistical analysis.
Since their physical school closure, 82.9% reported not having used public transport at all, while 52.3% had not talked face-to-face with someone not in their household. Around half (46.4%) found not being able to go out to shops problematic. Alcohol use was reported in 37.2% (11.0% increased usage, 14.0% reduced usage while 12.2% stayed the same). Use of cigarettes, e-cigarettes and vapes was reported in 17.6% (6.6% increased usage, 7.7% reduced usage while 3.3% stayed the same). Cannabis use was reported in 13.1% (3.6% increased usage, 6.4% reduced usage while 3.1% stayed the same). Having undergone mandatory self-quarantine was reported by 49.7%. 92.1% reported quarantining with their parents, 1.8% with family but without parents, and 5.5% with others.
Factors associated with depressive symptoms -Univariate analysis Depression was higher in those who reported previous depression, anxiety, and stress (p < 0.001). Higher levels of depression were also reported in those who had undergone mandatory self-quarantine, felt COVID-19 had affected their daily life, reported not using public transport since school closure, believed that they would have low chance of contracting COVID-19 themselves, and had no worries about going outside (p < 0.05). In addition, those who perceived problems with the consequences of social distancing, including not being able to meet friends, inability to eat out, inability to go shopping and online learning, all displayed higher levels of depression (p < 0.05) ( Table 1).
Those who reported use of alcohol, cigarettes/e-cigarettes/vapes, cannabis, and/or other drugs experienced higher levels of depression than those who never used them. Furthermore, those who experienced unchanged or increased use of alcohol, cigarettes/e-cigarettes/vapes and cannabis during lockdown experienced higher levels of depression than those who experienced reduced use of these substances (p < 0.001) (    (Table 3).
Anxiety was higher in those who reported previous depression, anxiety, and stress (p < 0.001). Higher levels of anxiety were also reported in those who reported not using public transport since school closure, and 'sometimes or regularly' had sleep problems due to thinking about COVID-19 (p < 0.05). In addition, those who perceived problems with the consequences of social distancing, including online learning, inability to eat out and inability to go shopping, all displayed higher levels of anxiety (p < 0.05). Conversely, the lowest levels of anxiety were found in those who were the most worried about going outside (p = 0.004) ( Table 3).
Those who reported use of alcohol, cigarettes/e-cigarettes/vapes, cannabis, and/or other drugs experienced higher levels of anxiety than those who never used them. Additionally, those who experienced unchanged or increased use of all four substance categories during lockdown experienced higher levels of anxiety than those who experienced reduced use (p < 0.05) ( Table 3).

-Multivariate analysis
We found that females (compared to males, OR = 3.075, 95% CI = 1.60-5.92) and participants who had not used public transport at all since the physical closure of their school (compared to those who sometimes used it, OR = 8.31, 95% CI = 2.49-27.755) had signi cantly increased risk of anxiety (Table 4). OR, odds ratio; CI, con dence interval.
Higher levels of anxiety were found to be signi cantly associated with an increase in levels of previous anxiety (OR = 4.61, 95% CI = 1.54-13.795), and previous stress (OR = 3.89, 95% CI = 1.52-9.92) during lockdown, compared to those who reported never having previous anxiety or stress. Those who reported decreased or equal levels of previous depression during lockdown still had higher levels of anxiety than those who never had previous depression before the lockdown (OR = 6.585, 95% CI = 2.14-20.30).
Factors associated with perceived stress -Univariate analysis Univariate analysis was conducted using chi-square test and t-test. p < 0.05 was considered signi cant.
df, degrees of freedom; SD, standard deviation; UK, United Kingdom.
Higher levels of high stress were found in Years 11 and higher (14.7% vs 3.0%, p < 0.001), females (17.2% vs 3.6%, p < 0.001) ( High stress levels were greater in those who reported previous depression, anxiety, and stress which had increased/worsened due to lockdown (p < 0.001). Higher levels of high stress were also reported in those who lived in rural areas, reported not using public transport since school closure, 'sometimes or regularly' had sleep problems due to thinking about COVID-19, had undergone mandatory self-quarantine, and perceived problems with online learning (p < 0.05) ( Table 6.1).
Those who reported use of cigarettes/e-cigarettes/vapes and cannabis experienced higher levels of high stress than those who never used them. Additionally, those who experienced unchanged or increased use of the two substances experienced higher levels of high stress than those who experienced reduced use (p < 0.05) ( Participants who experienced increased or unchanged alcohol use during lockdown were found to not have as high levels of high stress as those who had never used alcohol (OR = 0.27, 95% CI = 0.11-0.69) ( Table 6).

Discussion
We conducted an online survey study which found a high prevalence of mental health conditions among secondary school students across a range of countries during COVID-19 lockdown in May and June 2020. Approximately 60% had depression, 40% had anxiety and 10% experienced a high level of stress.
Being female enhanced depression and anxiety. Being enrolled in the last three years of high/secondary school enhanced depression. Changes in patterns of substance use were also signi cantly associated with anxiety and stress.
Although one must take into account the environment in which adolescents live in, as it will ultimately affect their mental health, it is clear to see that our ndings demonstrate a higher prevalence of depressive, anxiety and stress symptoms. Compared to previous studies done during arguably more normal times, our prevalence of depressive symptoms was higher than 53.2% in Norwegian secondary school students (20), 55.9% in Nigerian secondary school students (21), 52.9% in Chinese adolescents (22). Similarly, our ndings indicate a higher prevalence of anxiety compared to around 10% in Canadian secondary school students (23) and higher-education students from the UK (24) from studies conducted during non-COVID19 times. High stress level was also found to be more common than the 4% among Thai students aged 15-19 years (25) before COVID-19.
Furthermore, a recent study conducted on Chinese adolescents aged 12-18 years also demonstrated similar ndings of elevated prevalence (43.7% exhibiting depressive symptoms, 37.4% exhibiting symptoms of anxiety) during COVID-19 (15). There were no reports of stress prevalence among secondary school students during COVID-19.
In our study, being female was found to be signi cantly associated with higher levels of depression and anxiety. This was found to be in accordance with previous studies concerning lockdown mental health (9,26,27), as well as during more general times (28,29). However, Cao et al. did not nd gender to be signi cantly associative with higher levels of anxiety during COVID-19 lockdown (30).
Being enrolled in senior high school (Years 11-13 or Grades 10-12) was found to be signi cantly associated with higher levels of depression, but not anxiety, in our study. Zhou et al. found similarly signi cant associations with both anxiety and depression during COVID-19 (15).
A combination of emotions such as boredom, anxiety, depression and fear may lead to increased substance use as a means of coping (31). With many countries closing down shops and public services (32), with some even enacting coronavirus alcohol bans (33), many may nd themselves in forced abstinence (12,34). Access to recreational substances normally used which have been limited, for example due to lockdown or otherwise, can exacerbate mental health effects (10,11,35). We found that reports of decreased cannabis use were signi cantly associated with higher levels of depression. Furthermore, increased or unchanged alcohol use was found to be associated with lower levels of stress.
Despite likely being a protective factor in this study, adolescent alcohol use has been found to predict development of alcohol problems into young adulthood (36), so should be treated with caution. In times of lockdown, those with substance use disorders tend to be ignored (10). This problem is further worsened due to the fact that adolescents who use substances tend to not want to disclose their use, for example to their parents. Therefore, there is a chance that those concealing their use within their household may face adverse effects. Lack of access to supervised substance use may also increase hazardous use, due to interruption of opening hours of harm reduction services as well as general fears of COVID-19 infection among clients (37). The United Nations O ce on Drugs and Crime (UNODC) reported in May 2020 that COVID-19 may have adverse effects on drug supply chains. This may lead to harmful adaptations by both producers, such as reduced street purity, and users, such as a shift towards drug injection as well as sharing paraphernalia (38).
There are some limitations in this study. This is a cross-sectional study and we were therefore not able to assess any long-term impacts or progressions of mental health conditions like a longitudinal study would be able to. Furthermore, due to our use of snowball sampling, we were unable to record or know the number of people who had been formally 'invited' to take part in the survey. Moreover, we found that other studies examining the psychological impacts of lockdown, particularly concerning past outbreaks, assessed post-traumatic stress disorder (PTSD) as well. We did not choose to assess this as the progression of the COVID-19 pandemic is far from over. Different countries will also have been affected with varying severity, which could ultimately lead to different PTSD outcomes. Almost 60% of our participants lived in Thailand, where COVID-19 has struck relatively less hard. As of 7 September 2020, Thailand has had 3,445 COVID-19 cases, compared to 347,152 cases in the UK. Their death rates per million people are also extremely different, with 0.8 for Thailand, but 611 for the UK (18). Nevertheless, it will be important to assess it once lockdown ends, as studies have demonstrated the long-lasting PTSD caused by lockdown and quarantine (31).

Conclusions
In conclusion, amidst lockdown measures, around half of adolescents exhibited depression and/or anxiety. Particular attention must be paid to females, older adolescents and substance users. Girl-centred mental health support platforms (39,40) should be readily available, and tailored to t speci c countries' contexts. Schools must closely monitor and act upon any concerns which arise from their students, especially the more senior individuals who may be particularly stressed about academic commitments such as exam cancellations (13), university preparation and work experience opportunities. However, apart from their parents, schools must also monitor the child's mental health wellbeing in general as school forms a very important aspect of their life and these changes due to COVID-19 could be drastic for some. Harm reduction services must receive support to maintain service delivery, perhaps adapting and utilising innovative interventions such as telemedicine-delivered prescription and treatment (41), as well as a focus on more tailoring towards adolescent users.

Declarations
Ethics approval and consent to participate The study was approved by the Institutional Review Board of the Faculty of Medicine, Chulalongkorn University. Consent by action was obtained via a digitalised consent form, explaining the objectives and contents of the survey as well as potential risks and intended bene ts. Despite most participants being under 18, parental consent was waived due to the anonymous nature of the survey.

Consent for publication
Not applicable Availability of data and materials The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request. All data generated or analysed during this study are included in this published article.

Competing interests
The authors declare that they have no competing interests.

Funding
This research did not receive any speci c grant from funding agencies in the public, commercial, or notfor-pro t sectors.
Authors' contributions GP conceptualized and designed the study, collected data, performed formal analysis, wrote the rst draft of manuscript, reviewed and edited the manuscript. RK designed the study, supervised data collection, performed formal analysis, reviewed and edited the manuscript. Both authors read and approved the nal manuscript.