A rapid review investigating the potential impact of a pandemic on the mental health of young people aged 12–25 years

Objectives: In March 2020, the World Health Organization (WHO) officially declared the spread of coronavirus disease 2019 (COVID-19) as a pandemic. Adolescence and early adulthood are peak times for the onset of mental health difficulties. Exposure to a pandemic during this vulnerable developmental period places young people at significant risk of negative psychological experiences. The objective of this research was to summarise existing evidence on the potential impact of a pandemic on the mental health of 12–25 year olds. Methods: A rapid review of the published peer-reviewed literature, published between 1985 and 2020, using PsycINFO (Proquest) and Medline (Proquest) was conducted. Narrative synthesis was used across studies to identify key themes and concepts. Results: This review found 3,359 papers, which was reduced to 12 papers for data extraction. Results regarding the prevalence of psychological difficulties in youth were mixed, with some studies finding this group experience heightened distress during an infectious disease outbreak, and others finding no age differences or higher distress among adults. Gender, coping, self-reported physical health and adoption of precautionary measures appear to play a role in moderating the psychological impact of an infectious disease outbreak. Most studies were conducted after the peak of an epidemic/pandemic or in the recovery period. Conclusions: More longitudinal research with young people, particularly adolescents in the general population, before and during the early stages of an infectious disease outbreak is needed to obtain a clear understanding of how best to support young people during these events.


Introduction
A pandemic is characterised by the simultaneous worldwide spread of a novel infectious disease and typically causes widespread economic, social and political disruption (Doshi, 2011;Kelly, 2011). Although infrequent, some evidence suggests that globalisation has increased the likelihood of their occurrence (Madhav et al. 2017). Individuals affected by an infectious disease outbreak, such as a pandemic, often experience increased anxiety, particularly around contracting the illness, a higher incidence of mental health difficulties and heightened feelings of helplessness and stigma (Hall et al. 2008;Douglas et al. 2009;Rubin et al. 2010;Sim et al. 2010;Kelly, 2020). Mitigating the impact of a pandemic typically requires a large-scale, coordinated public health response [World Health Organization (WHO), 2017]. Risk-based measures including social/physical distancing, travel or movement restrictions, school/business closures and enforced quarantine to slow the spread of the disease and lessen its impact on the health system are often taken (WHO, 2018a). Thus, the negative psychological impact of a pandemic can be compounded by the public health measures introduced to contain the virus (Van Bortel et al. 2016;Holmes et al. 2020). Indeed, a series of recent reviews on the effects of quarantine and social isolation indicate they can lead to prolonged mental health difficulties (Brooks et al. 2020;Hossain et al. 2020;Loades et al. 2020).
Young people between 10 and 24 years of age account for almost a quarter of the total global population (Gupta, 2014;The World Bank, 2018). Adolescence and early adulthood are critical periods of development, which can shape the likelihood, severity and course of mental health problems (Kessler et al. 2007;Kessler et al. 2012). Many young people are attending school or university, which are among the first institutions to close as part of infection prevention measures, leaving them isolated from their peer groups as well as primary help-seeking and support facilities (Fegert & Schuzle, in press;Stevenson et al. 2009; Van et al. 2010;WHO, 2017;Holmes et al. 2020;Kelly, 2020;WHO, 2017). Additionally, family distress is often high during a pandemic and young people may find themselves coping with feelings of distress and anxiety in the face of compromised support structures (Douglas et al. 2009).
On 11th March 2020, the WHO officially declared the spread of the coronavirus disease 2019 (COVID-19) as a pandemic. At the time of writing, there were over 4.3 million confirmed cases of COVID-19 across 188 countries/regions, with over 290 000 associated deaths (John Hopkins University, 2020). Resulting public health responses have included widespread restrictions on social activity and closures of public spaces, schools and non-essential businesses (Bedford et al. 2020;Sohrabi et al. 2020). Emerging research on the COVID-19 outbreak indicates that over half (53.8%) of individuals rate the psychological impact of the pandemic as moderate to severe . Another nationwide study with 52 730 respondents across 36 provinces in China, the country at the centre of the COVID-19 outbreak, found that over one-third (35%) of individuals reported symptoms of psychological distress (Qiu et al. 2020). Others have suggested that individuals with confirmed and suspected cases of COVID-19 may experience fear of severe disease consequences and the contagion, and have increased risk of suicide (Li et al. 2020, Lin, 2020. Exposure to the COVID-19 pandemic during a vulnerable developmental stage places young people at a greater risk of the negative psychological impacts of such an event (Holmes et al. 2020). The objective of this rapid review was to summarise the information available about the potential impact of a pandemic on the mental health of young people aged 12-25 years. This age range was selected as it reflects international trends in current service provision for young people, research in this area (Hetrick et al. 2017) and the WHO definition of youth (United Nations [UN], 2013).

Rapid review methods
A rapid review was conducted to capture relevant studies related to the research question. Rapid reviews condense the systematic review process to provide robust evidence-informed decisions in a cost-effective manner. This method is particularly appropriate when information and evidence is required quickly and in times of crisis (Tricco et al. 2017). The review was documented using the Preferred Reporting items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. The protocol was registered with PROSPERO (CRD42020177796).
This review included all types of studies that explored how the mental health (outcome) of young people aged 12-25 years (population) could be affected by an exposure to a pandemic (exposure). This review was limited to studies relating to exposure to an infectious disease outbreak classified as either an 'epidemic' or 'pandemic', as these terms are often used interchangeably in the literature. This includes infectious disease outbreaks such as COVID-19, H1N1/swine flu, severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), Ebola and HIV/AIDS. Studies examining treatments or risk factors for infectious diseases or exclusively focusing on populations such as healthcare workers were excluded. The focus was on studies where the majority of participants were aged 12-25 years, or where a sub-group of participants was clearly identified as being within this age range. For the purposes of the review, the WHO (2018b, para. 2) definition of mental health as 'a state of well-being in which every individual realises his or her own potential, can cope with the normal stresses of life, can work productively and fruitfully and is able to make a contribution to his or her own community'. There was no geographical restriction on papers. The search was restricted to English, peerreviewed abstracts and titles in PsycINFO (Proquest) and Medline (Proquest) from January 1985 to March 2020. Further details on the rapid review method and our search and selection strategy are provided in Appendix A.

Consultation with experts
In keeping with recommendations from the Cochrane Rapid Reviews Methods Group (Garritty et al. 2020), the research team sought input from N = 30 youth mental health professionals working in a large youth mental health organisation based in Ireland in refining our research question. Respondents provided positive feedback to the research team and highlighted the potential application of the findings in the field.

Data synthesis
A quantitative synthesis proved to be inappropriate due to the heterogeneity of study designs, contexts and outcomes in the literature. Thus, a narrative synthesis across studies was used to identify key themes and concepts. Narrative synthesis refers to an approach to that relies chiefly on the use of words and text to summarise and explain the findings of the synthesis (Popay et al. 2006). First, the characteristics and findings of individual studies were tabulated, eligible studies were read and re-read independently by members of the research team and initial themes were generated (i.e. preliminary synthesis). As per Popay et al's. (2006) guidelines on narrative synthesis, variations in outcomes, study design, populations and content were noted, and relationships within and across studies were documented. Themes were then discussed and reviewed by the whole research group and against the full data set. As themes emerged from a review of the primary data, this remains an inductive approach (Atkins et al. 2008).

Search results
Initial searches yielded 3,359 search results, which was reduced to 3,127 after duplicates were removed. The screening review process is illustrated in Fig. 1. Initially, two members of the research team (MT, BMcK) reviewed the titles and abstracts of approximately half the papers each to make an initial assessment of relevance. Similar to Brown et al. (2020), following the initial search, papers that related to the HIV/AIDS pandemic were excluded as the mode of transmission is different (i.e. it is not an airborne transmission). A random sample of 10% of titles/ abstracts were examined by two additional reviewers (AB, AOR). Discrepancies (N = 17) were resolved through discussion. After this initial screening, 3,096 papers failed to meet the inclusion criteria, leaving 31 papers for full screening by two members of the research team (MT, BMcK). Forward and backward reference checking of key articles yielded a further six studies, leaving 37 papers for full screening.
After full screening, a further 25 papers failed to meet the inclusion criteria, leaving a final list of 12 papers for data extraction. Data were extracted onto a template by two researchers (MT, BMcK). Variables to be extracted comprised of the following: country of origin, study design, aims, method, participant characteristics, method of data analysis and key findings. This information was stored on a Microsoft Excel database. The remaining papers were examined using the appropriate Joanna Briggs critical appraisal checklist Rapid review of youth mental health during a pandemic 3 (Aromataris et al. 2015). These checklists have been widely used in rapid reviews and allow for the quick evaluation of study quality.

Study characteristics and quality
The studies included seven prevalence studies, three cross-sectional studies, one longitudinal study and one case-control study (see Tables 1 through 3). Most (5/12) of the studies were undertaken in China, followed by Taiwan (2/12) and Hong Kong (2/12), with one each from Canada, Sweden and Saudi Arabia. Half of the studies (6/12) included 12-25-year-olds as part of larger studies with members of the public, 4/12 were conducted with university students, one with medical students and one with children and young people who had developed narcolepsy after receiving the H1N1 vaccine. The majority of studies were related to the SARS outbreak (9/12), and one each to H1N1, MERS and COVID-19, respectively. Sample sizes were mostly modest, and varied from N = 38 (Szakács et al. 2015) to N = 4,481 (Leung et al. 2005). Two-thirds of the studies were rated as being of moderate quality (8/12), while one-third were rated as high quality (4/12).

Narrative synthesis
Three major themes emerged from the narrative synthesis: prevalence of psychological difficulties among youth, factors moderating psychological difficulties and aspects of infectious disease outbreak causing distress.

Prevalence of psychological difficulties
There was some variation in findings regarding the prevalence of psychological difficulties among youth affected by an infectious disease outbreak. Four studies reported high anxiety or distress among young people recruited from the general population, university and health services during or following an outbreak (Bergeron & Sanchez, 2005;Peng et al. 2010;Main et al. 2011;Szakács et al. 2015), while another found student status was predictive of greater psychological distress . However, other studies found older age groups reported higher levels of distress (25-44 -year-olds; Leung et al. 2005), perceived the pandemic had a greater impact on their mental health (25-34-year-olds and those aged 50þ; Lau et al. 2005) or were more pessimistic (those aged 60þ; Peng et al. 2005). Two studies found no age differences (Ko et al. 2006;Mihashi et al. 2009). Additionally, one study with university medicine students found that participants generally reported low levels of anxiety (Al-Rabiaah et al. 2020). A final study found young people in epidemic areas, which were described as 'the eye of the storm', were less anxious than those in non-epidemic areas, although the sample size was small (Xie et al. 2011). As shown in Tables 1 through 3, there was significant variation in how mental health outcomes were measured, with some studies using author-designed measures, and others using standardised measures of anxiety [e.g. Depression Anxiety Stress Scale (DASS-21), Henry & Crawford, 2005; State-Trait Anxiety Inventory (STAI), Spielberger et al. 1983; General Anxiety Disorder (GAD-7); Spitzer et al. 2007], psychological disorder [e.g. General Health Questionnaire (GHQ-30), Goldberg & Williams, 1988] or distress [e.g. Brief Symptom Rating Scale (BSRS-5), Lung & Lee, 2008; Impact of Event Scale (IES-R), Weiss, 2007].

Factors moderating psychological difficulties
Gender was only examined in three studies among the target age group. Two studies found female university students reported significantly higher levels of psychological distress than their male peers (Bergeron & Sanchez, 2005;Al-Rabiaah et al. 2020). The results from a third study indicated male and female university students were equally affected by the SARS epidemic, although female students reported higher life satisfaction (Main et al. 2011). This study also found that, in general, all types of coping (i.e. active coping, avoidant coping and support focused coping) served as a buffer against the negative impact of stressors on perceived health, although female students reported less passive coping than their male peers. Additionally, Gan et al. (2004) reported that Chinese university students used less flexible coping strategies when dealing with SARS-related stress in comparison to daily life stresses, mirroring the coping reactions of individuals with depression.
It was notable that few studies asked participants to provide information on their physical health, given many individuals often experience physical illness during infectious disease outbreaks. Although four studies (Ko et al. 2006;Mihashi et al. 2009;Main et al. 2011;Wang et al. 2020) found self-reported health status was significantly associated with psychological difficulties, only one of these presented results for the target age group. Here, the authors observed a significant moderate positive correlation between psychological symptoms and general health among university students (Main et al. 2011). Another study looked at SARS-related vigilance among the general population, and found participants consistently thinking about whether or not they had contracted SARS was linked with higher levels of anxiety (Xie et al. 2011). Finally, two studies examined the relationship between the adoption of precautionary measures and psychological distress among young   • No significant gender difference in psychological symptoms (d = .01 a ). Females reported significantly higher levels of life satisfaction than males (d = .3 a ) • Experience of SARS-related stressors was positively associated with psychological symptoms (β = .1) • Interaction between SARS-related stressors and coping predicted perceived general health (β = .1) but not psychological symptoms (β = −.1) or life satisfaction (β = −.02) • Student status was significantly associated with higher psychological impact (β = .2), stress (β = .1), anxiety (β = .2) and depression (β = .1) compared to those who were employed • No significant difference in psychological impact, stress, anxiety or depression between age groups (β = .  people. Results from both studies indicated that the adoption of precautionary measures such as avoiding others and greater change in hygiene habits was significantly associated with higher levels of anxiety/stress (Xie et al. 2011;Al-Rabiaah et al. 2020).

Aspects of infectious disease outbreak causing distress
The timing of data collection varied across studies. With the exception of one longitudinal study, which comprised multiple phases of data collection with members of the general population during and after a SARS outbreak (Leung et al. 2005), most studies were conducted when an outbreak had been controlled or after the resolution of this event. While the longitudinal study did show an overall decrease in anxiety in a population from the peak of an epidemic to post-epidemic, and this trend was observed among 18-24-year-olds, results were not significant for this age group (Leung et al. 2005) In addition to studies looking at general difficulties during a pandemic, others focused on events linked to an infectious disease outbreak. A small number focused on social isolation or quarantine among youth. As noted earlier, in one study, the authors found that participants in epidemic areas were generally less anxious than those in non-epidemic areas (Xie et al. 2011). A second study found exposure to more SARS stressors, including having to cancel planned activities, predicted psychological difficulties among university students (Main et al. 2011). Other studies pointed to a relationship between being quarantined or living with restrictions and psychological well-being, but results were not disaggregated by age (Ko et al. 2006;Mihashi et al. 2009;Peng et al. 2010).
Finally, there were two studies that looked at specific factors associated with a pandemic. One study examined media use and its link to mental health among university students, but found anxiety levels were not associated with the use intensity of any type of media (Bergeron & Sanchez, 2005). Another study examined psychological difficulties among children and adolescents who had developed narcolepsy after receiving a vaccine for H1N1, and found higher prevalence of psychiatric disorders among this group compared to those who had developed narcolepsy due to other reasons (Szakács et al. 2015).

Discussion
The purpose of this rapid review was to synthesise and describe the available evidence on the potential impact of a pandemic on young people's mental health. There is generally consensus in the literature that rates of anxiety and depression across countries among adolescents and young adults have increased (Collishaw, 2015;Mojtabai et al. 2016;Dooley et al. 2019;Patalay & Gage, 2019). How young people's mental health is affected by an infectious disease outbreak and the public health measures to control such an outbreak is unclear. This review revealed some studies in this area point to heightened vulnerability among youth, others suggest adults are more affectedpossibly due to increased physical health risks (Mackay & Arden, 2015) and a small number report no age differences. The research almost consistently indicates females report higher levels of distress, which mirrors the broader literature with this age group (Dooley et al. 2019;Patalay & Gage, 2019;Wiens et al. 2020).
The disparity observed may be somewhat explained by the different instruments used to assess mental health/psychological well-being. While several studies used standardised questionnaires to examine a particular aspect of distress, others used one-item authordesigned measures. It is also worth noting that most (75%) of the studies were conducted in Chinese or other Eastern cultures, where a number of recent infectious disease outbreaks have occurred. Eastern and western cultures typically respond differently to negative emotions (Furlong & Finnie, in press). Individuals from collective cultures tend to report more somatic symptoms than psychological symptoms (Ryder et al. 2008), and coping strategies are also likely to vary depending on culture (Chun et al. 2006), pointing to the need to consider the larger social and cultural context in addition to the situational context of a pandemic (Wong et al. 2006). Indeed, two studies point to the importance of adaptive coping styles in responding to adversity during an infectious disease outbreak. Maladaptive coping is a risk factor for the development of psychological difficulties after a pandemic or natural disaster (Coetzee & Spangenberg, 2003;Naushad et al. 2019).
It was surprising that the majority of the research included in this review was conducted in the latter stages or after an infectious disease outbreak. None of the studies reviewed included data collection points prior to and after an infectious disease outbreak, meaning the ability to infer changes in youth mental health as a direct result of the outbreak is significantly limited. There is a real need to conduct more longitudinal research, particularly prior to and during the peak stages of an infectious disease outbreak, when young people are most likely to be affected by public health measures or feel particularly anxious about their physical health. Although previous research has established a link between the impact of social isolation, quarantine and restricted movements and distress (Brooks et al. 2020;Hossain et al. 2020;Loades et al. 2020), we could not draw firm conclusions from this review on how young people are affected by such measures during a pandemic. The COVID-19 pandemic is much more widespread than the other infectious disease outbreaks described in many of the papers included in this review, and the long-term economic effects are likely to be more significant, particularly for young people [Oswald & Powdthavee, 2020;Institute for Fiscal Studies (ISF), 2020]. Previous research has indicated youth and parent unemployment can have a significant psychological impact on young people (Fergusson et al. 2001;Virtanen et al. 2016). Conversely, the successful recovery of national economies appears to crucially depend on the mental health of the population (WHO, 2011).
It is worth noting that most of the studies included in this review used convenience, non-representative samples. Although seven studies reported some element of random sampling, the samples were typically restricted to a particular geographic or educational setting. Only two studies reported random sampling based on a specified sampling frame, thus limiting the ability to make accurate inferences about prevalence. The studies were also typically comprised of university students, and none were conducted solely with 12-25-year-olds. Only four studies included young people under the age of 18, meaning we are limited in our ability to make inferences about prevalence particularly in terms of how adolescents may be affected by a pandemic. Additional research with young people with preexisting mental health difficulties or those experiencing challenges with regards to their personal, family or social circumstances are warranted, as this group may be disproportionally affected by the mediumand long-term social effects of COVID-19, and resource allocation for youth mental health services is generally insufficient (Brown et al. 2020;Furlong & Finnie, in press;Li et al. 2020). The voice of young people is also notably absent from the literature on this topic. Patient and public involvement is critical to understanding people's lived experiences, yet the methods adopted in the existing body of research do not actively promote youth voice. It is important any research with young people is ethically robust and researchers view COVID-19 mental health research as a sensitive topic, where attention is paid to the safeguards needed to protect the well-being of participants (Townsend et al. 2020). This is particularly salient for research with young people under the age of 18, where legal and developmental considerations limit their capacity to consent independently and parental support may be required (Hiriscau et al. 2016).

Strengths/limitations of study
This review is the first to focus on the mental health impacts of a pandemic on the 12-25-year-old cohort, which is a target age group for a growing number of youth mental health services internationally (Hetrick et al. 2017). Incorporating a consultation with mental health professionals to refine the research question, collaborating with a young person as an author on the rapid review team, adopting a systematic process of study selection and rigorous synthesis methods are all key strengths of the review.
However, the review conclusions are ultimately limited by the quality of the primary studies reviewed. Although all of the studies identified in this review were rated as moderate or high in terms of quality, convenience sampling, an absence of strategies to deal with confounding factors, variation in measures used to assess the primary outcome (mental health) and heterogeneity of outcome measures in the studies identified are all limitations of the review. As noted above, there is also a notable absence of studies with adolescents or incorporating youth perspectives in the reviewed studies. In addition, the predominance of crosssectional data gathered in Eastern cultures in the period before/after a pandemic limits our ability to draw conclusions about the immediate or subsequent long-term impacts of a pandemic on youth mental health. Further, slightly more than half of the studies included respondents outside the 12-25-year-old age group, most of which contained only limited, albeit valuable, information that was disaggregated for this age cohort. Additionally, in order to quickly collate the evidence available, this review employed single-reviewer screening with 10% verification by a second reviewer, which is common in rapid reviews (Abou-Setta et al. 2016). Finally, the review focused on peer-reviewed, English language publications and may not have identified all related existing and emerging published/ unpublished publications related to pandemics.

Recommendations for practice
Few studies have considered the collective impact of biological, social and psychological risk and protective factors on youth mental health, meaning our ability to make recommendations about how to effectively intervene and impact on young people's mental health during a pandemic is limited. However, some considerations for practice and policy are evident. First, this review highlights mental health should be considered as part of a holistic response to the COVID-19 outbreak. Second, while cultural context must be considered, there are indicators that adaptive coping styles can support young people's capacity to navigate through an uncontrollable event such as a pandemic, pointing to an area of intervention for mental health service providers. Psychological interventions incorporating cognitive behavioural therapy or problem-solving therapy may be valuable, and could be delivered online. Delivery of online services and the integration Rapid review of youth mental health during a pandemic 11 of e-therapy tools have begun in many countries as a result of the COVID-19 outbreak (Wind et al. 2020). Community-based workshops or health promotion campaigns could also focus on the promotion of adaptive coping styles. Finally, this review highlights the need to take factors such as age and gender into account when delivering mental health campaigns to support populations in the aftermath of COVID-19.

Conclusion
During an infectious disease outbreak, the focus of research and action is often on the medical and public health communities, where it has typically (rightly) been on the identification of the responsible agent, clinical presentation and treatment of the disease (Leung et al. 2005). However, it is important to pay attention to the ways a pandemic can impact on mental health. To the best of the author's knowledge, this is the first time the evidence on young people's mental health during a pandemic has been synthesised. On the basis of the review, we are unable to determine the extent by whichif at allyoung people's mental health is affected by a pandemic, what factors may mitigate the impact of a pandemic on mental health, and how culture/context could affect this impact. The review highlights there has been minimal consideration of how this group can been affected by a pandemic, and points to an urgent need for more research on this area, particularly with adolescents. The COVID-19 crisis has been described as 'unprecedented, prolonged and unpredictable' (Pūras, 2020) and the impact on youth well-being needs to be considered as a priority.