Interventions to improve children's access to mental health care: a systematic review and meta-analysis.

AIMS: Mental disorders in children are a significant and growing cause of morbidity worldwide. Although interventions to help overcome barriers along the pathway to accessing health care for children with mental disorders exist, there is no overview of randomised controlled trials (RCTs) on these interventions as yet. This study aimed to systematically identify RCTs of interventions to improve access to mental health care for children and synthesise them using a conceptual framework of access to health care.
METHODS: This systematic review was performed following a predefined protocol registered with PROSPERO (ID: CRD42018081714). We searched the databases MEDLINE, EMBASE, PsycINFO and CENTRAL for RCTs up to 15 May 2019 using terms related to the concepts 'young people,' 'mental disorders' and 'help-seeking interventions' and scanned reference lists from relevant studies. Two reviewers independently screened all identified articles in a two-stage process, extracted results on outcomes of interest (knowledge, attitudes, intentions, help-seeking, accessing care, mental health outcomes and satisfaction), assessed the risk of bias and conducted meta-analyses where deemed appropriate.
RESULTS: After screening 5641 identified articles, 34 RCTs were eligible for inclusion. Eighty per cent of universal school-based interventions measuring knowledge (n = 5) and 67% measuring attitudes (n = 6) reported significantly better results compared with controls on those outcomes, whereas 20% measuring access to care (n = 5) and none measuring mental health outcomes (n = 7) did. In contrast, 71% of interventions targeting at-risk individuals (n = 21) reported better access to care compared with controls, while just 33% (n = 6) did for mental health outcomes. For satisfaction with care, this proportion was 80% (n = 5). Meta-analyses of interventions measuring initial appointment attendance yielded combined odds ratios of 3.11 (2.07-4.67) for appointment reminder interventions and 3.51 (2.02-6.11) for treatment engagement interventions. The outcomes for universal school-based interventions were heterogeneous and could not be summarised quantitatively through meta-analysis.
CONCLUSIONS: To have a population-level effect on improving children's access to mental health care, two-stage interventions that identify those in need and then engage them in the health-care system may be necessary. We need more evidence on interventions to target contextual factors such as affordability and infrastructural barriers.

Introduction

Mental disorders are one of the most significant causes of disability-adjusted life-years worldwide, and they continue to grow in importance as a major contributor to the global burden of disease (GBD 2015 DALYs and HALE Collaborators, 2016). Because mental disorders usually first occur early in life (Kessler et al., 2005) and are characterised by recurrent episodes and symptoms that strongly affect work capacity (Simon et al., 2001), they have a significant impact on public health and society.

Childhood and adolescence are particularly critical periods for the identification and treatment of mental disorders. At 45% of the overall burden of disease in 15–19 year-olds, mental health issues are the leading cause of disability in adolescents (The Lancet, 2017). In addition, young patients with a mental disorder have a lower probability of receiving treatment and a longer delay between disease onset and first treatment compared with adults (Christiana et al., 2000; Wang et al., 2005; Iza et al., 2013). Despite the magnitude and importance of mental health problems in childhood and adolescence, international studies have consistently revealed a treatment gap: estimates of the gap between those in need of mental health care and those who access it exceed 50% (Saxena et al., 2007).

Levesque et al. (2013) define access to health care as ‘the opportunity to reach and obtain appropriate health-care services in situations of perceived need for care’ (Levesque et al., 2013). They have proposed a comprehensive conceptual framework describing accessing health care as a series of steps beginning with the opportunity to perceive health-care needs that can lead to opportunities to seek health care, reach health-care services, utilise health-care services and ultimately have health-care needs fulfilled (Levesque et al., 2013). At each stage, supply-side dimensions of accessibility of services (e.g., approachability, availability or affordability) interact with demand-side abilities of persons (e.g., abilities to perceive, pay or engage) to determine access to health care (see Appendix 1) (Levesque et al., 2013). In other words, the care that is obtained depends on the interplay of characteristics of individuals, such as their socio-economic status or where they live, and those of services and the environment, such as how much services cost and where they are located. Potential barriers that could explain the treatment gap can be found at each transition from step to step along this pathway to accessing care (Levesque et al., 2013). Barriers to mental health help-seeking in young people include lack of knowledge about services and stigma about mental health problems (Gulliver et al., 2010). As an example of barriers on the supply side, paediatricians perceive a wide variety of organizational hindrances, including inadequate reimbursement and lack of time and space, and many feel they lack the training and confidence to treat mental disorders (Horwitz et al., 2007).

To close the treatment gap, interventions targeting one or more dimensions of accessibility of services and/or abilities of persons have been designed to address the barriers along the pathway to accessing care (e.g., screenings, health literacy promotion); however, there is little high-quality evidence on these interventions (National Institute for Health and Clinical Excellence, 2011). Moreover, systematic reviews conducted in the past on interventions to improve access to mental health care for children and adolescents have limited searches to specific types of interventions and disorders (Ingoldsby, 2010; Gulliver et al., 2012; Lindsey et al., 2014; Anderson et al., 2017; Dunne et al., 2017; Richardson et al., 2017). This study thus aimed to systematically identify randomised controlled trials (RCTs) of all interventions designed to improve access to mental health care for children along the entire pathway to accessing care, describe them using Levesque et al. (2013)'s conceptual framework of access to health care (Levesque et al., 2013) and conduct meta-analyses for intervention types with comparable outcomes.

Methods

The methods used for this systematic review are based on the Centre for Reviews and Dissemination's guidance for undertaking reviews in health care (Centre for Reviews and Dissemination, 2009), and our reporting follows the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) (Moher et al., 2009). A PRISMA checklist can be found in Appendix 2. We registered our systematic review protocol with the International Prospective Register of Systematic Reviews (PROSPERO, ID: CRD42018081714).

Types of participants

We included interventions designed for children and adolescents <19 years old, both from the general population and vulnerable groups. If the age range exceeded 18 years old, the intervention was only included if more than 50% of the ages considered were under 19. Interventions that addressed the following disorders from the International Classification of Diseases, 10th Revision (ICD-10) (World Health Organization, 1992) as well as suicidal ideation were considered: F10–F59 and F90–99 (all mental disorders except for mental disorders due to known physiological conditions, disorders of adult personality and behaviour, intellectual disabilities and pervasive and specific developmental disorders including autism spectrum disorders). We also included studies that targeted children with emotional or behavioural problems since children are not always given a specific diagnosis.

Types of interventions

Any intervention designed to improve access to mental health was included; thus, the intervention could target any one of the five supply-side dimensions or five demand-side abilities included within the conceptual framework. Examples of specific intervention targets are listed next to each dimension or ability in Appendix 1. For example, an intervention could change where services are offered or deliver services via the Internet (National Institute for Health and Clinical Excellence, 2011). The interventions could target the child or adolescent directly or others, including parents/caregivers, teachers, friends or health-care professionals (potential helpers).

Types of outcome measures

We defined outcomes using the conceptual framework and expanded upon these using conceptualisations from previous systematic reviews on help-seeking and treatment engagement interventions (Gulliver et al., 2012; Lindsey et al., 2014). Outcomes at all steps in the process of accessing health care were included in the review: knowledge about accessing mental health care, changed attitudes or beliefs about seeking care, intentions to seek care, help-seeking attempts to access health-care services (successful or not) or action taken by a potential helper, mental health outcomes and satisfaction with health-care services. For a study with outcomes on health measures and satisfaction with care to be included in the analysis, the study also had to measure access to care as an outcome. We excluded studies for which it was not possible to calculate any effect sizes.

Search methods for identification of studies

We performed the literature search on 15 May 2019 in the following electronic databases: MEDLINE, EMBASE, PsycINFO and the Cochrane Central Register of Controlled Trials (CENTRAL). The search strategy included terms relating to the concepts ‘young people,’ ‘mental disorders’ and ‘help-seeking interventions.’ The full search strategy can be found in Appendix 3. Publications not originally published in English were excluded from the search. We enhanced our search by scanning the reference lists of papers (both primary studies and reviews) that were identified by the database search. Duplicates were removed during the title and abstract screening.

Selection of studies and data extraction

Two reviewers (LW, DG) independently assessed the title and abstract of all identified papers, recorded their decision about whether the paper should be included for full-text assessment and discussed discrepant decisions until a consensus was reached. All papers deemed potentially eligible by the reviewers were included in the full-text assessment, in which the two reviewers decided on study inclusion based on the inclusion criteria and discussed any discrepant decisions until they reached a consensus.

The two reviewers independently extracted data on the following study characteristics: title, first author, year, country, study design, age range, intervention setting, condition in focus, sample size, response rate, intervention condition, control condition, length of intervention, evaluation time points, method of outcome assessment and results.

Assessment of risk of bias in included studies

Two reviewers (LW, DG) assessed the risk of bias of each article using the Cochrane Collaboration's tool for assessing risk of bias in randomised trials (Higgins et al., 2011) and discussed discrepant evaluations until they reached a consensus. Because our review included a large variety of interventions and outcomes, we could rarely assess the heterogeneity, imprecision and indirectness beyond a single or a few studies and therefore decided against using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach (Guyatt et al., 2011) to judge the overall quality of evidence. Instead, we used the risk of bias assessment as an indicator of the quality of evidence.

Data synthesis and measures of effect

We mapped the study results using the conceptual framework by Levesque et al. (2013) by target of intervention (Fig. 2) and by outcome (Fig. 3). For dichotomous outcomes, we extracted or calculated the odds ratio and 95% confidence interval, whereas, for continuous outcomes, we calculated the standardised mean difference and 95% confidence interval using Cohen's d with the package ‘esc’: Effect Size Computation for Meta Analysis in R (Lüdecke, 2017).

Fig. 2.

Target of interventions.

Fig. 3.

Significance of interventions' effect on targeted outcomes.

For intervention types with comparable outcomes, we conducted meta-analyses using the inverse variance method. We calculated a fixed-effects model if I2 was <30% and both fixed and random effects models if I2 was >30% using the package ‘meta’: General Package for Meta-Analysis in R (Schwarzer, 2007).

Results

Results of the search and excluded studies

The electronic search yielded 5688 articles, and an additional 43 records were identified through hand searching. Of these 5731 records, 5641 unique studies remained after duplicates were removed. A total of 71 articles were considered eligible for full-text screening following the title and abstract screening. During the full-text screening process, 37 articles were excluded; the full list of articles excluded along with reason for exclusion can be found in Appendix 4. The remaining 34 articles were included in the systematic review. For an overview of the search and screening process, please see the study flow diagram (Fig. 1).

Fig. 1.

Study flow diagram.

Included studies

A summary of the characteristics of the 34 RCTs identified through the two-stage screening process can be found in Appendix 5. These studies fell into two main categories: (1) universal school-based interventions targeting the general population (13 studies) and (2) interventions to engage at-risk individuals who had already been identified by the health-care system (21 studies). The vast majority of these studies were conducted in the USA (22 studies); the rest were conducted in Australia (five studies), UK (three studies), Canada (two studies), Portugal (one study) and Israel (one study).

The interventions in the first study category were designed to improve outcomes for general mental health problems, mental distress, suicide, depression and attention-deficit hyperactivity disorder. All studies in the second category took place in health-care settings (e.g., primary care, emergency department, mental health agency) and targeted general mental health problems, behavioural health problems, suicide, depression, substance abuse and conduct disorder. Interventions designed to help younger children access care tended to be addressed towards caretakers, whereas interventions targeting older age groups tended to address the adolescent directly.

Figure 2 provides an overview of the step or steps along the pathway to accessing care that each intervention targeted. Interventions within the first category exclusively targeted service providers' approachability (i.e., service providers making their existence known to individuals) and the abilities of individuals to perceive a need for and to seek care. These interventions included educational curricula, live or virtual contact with a mentally ill person, screenings and helper training programs. The vast majority of engagement interventions from the second category mostly targeted service providers' appropriateness or individuals' ability to engage. Forty-eight per cent (10/21) of these interventions consisted of programs to engage and motivate patients or to improve service providers' communication skills (henceforth called treatment engagement interventions), while 24% (5/21) involved using a telephone or letter reminder mechanism to improve first appointment attendance (henceforth called appointment reminder interventions). Just one intervention was infrastructural in nature and involved providing onsite mental health services for primary care patients. None of the identified studies targeted the acceptability (cultural and social factors that make it possible for individuals to accept services) of service providers, affordability of care, or individuals' personal ability to reach (e.g., their personal mobility or support from their social network) or pay for care.

Risk of bias in included studies

The results of the risk of bias assessment can be found in Table 1. The randomisation procedure was not described in half of the studies, and two studies described a non-random sequence generation procedure. Details on allocation concealment were only provided in 21% of the studies. In all studies except for one, it was unclear whether a lack of blinding of participants and personnel would influence the outcome. However, we judged that a lack of blinding of outcome assessment would not have an impact on the outcome since most outcomes were evaluated either by questionnaire or service use records. All but one study had a low risk of bias for incomplete outcome data. Three studies did not report all outcomes and three studies had other sources of potential bias.

Table 1.

Risk of bias of included studies

	a.	b.	c.	d.	e.	f.	g.*
1. Aseltine et al. (2007)
2. Campos et al. (2018)
3. Hart et al. (2018)
4. Howard et al. (2018)
5. Husky et al. (2011)
6. Jorm et al. (2010)
7. Klingman and Hochdorf (1993)
8. Morgan et al. (2019)
9. Painter et al. (2017)
10. Perry et al. (2014)
11. Saporito et al. (2011)
12. Sayal et al. (2010)
13. Sharpe et al. (2017)
14. Asarnow et al. (2005)
15. Asarnow et al. (2011)
16. Coker et al. (2019)
17. Donohue et al. (1998)
18. Fristad et al. (2003)
19. Gadomski et al. (2010)
20. Grupp-Phelan et al. (2012)
21. Gully et al. (2008)
22. Kourany et al. (1990)
23. Lieberman et al. (2006)
24. MacLean et al. (1989)
25. McKay et al. (1996a)
26. McKay et al. (1996b)
27. McKay et al. (1998)
28. Parrish et al. (1986)
29. Planos and Glenwich (1986)
30. Richardson et al. (2014)
31. Stern et al. (2015)
32. Stevens et al. (2009)
33. Szapocznik et al. (1988)
34. Wiseman and McBride (1998)

a. Random sequence generation; b. Allocation concealment; c. Blinding of participants and personnel; d. Blinding of outcome assessment; e. Incomplete outcome data; f. Selective reporting; g. Other bias; Low risk of bias; High risk of bias; Unclear risk of bias.

*Reasons for assessment of high risk of bias: Husky et al. (2011): Consent obtained after randomisation; Jorm et al. (2010): Some schools switched into another group and randomisation of schools did not occur after baseline assessment; Lieberman et al. (2006): procedure for outcome assessment was different for intervention and control groups.

Although we did not formally grade the quality of evidence using the GRADE approach (Guyatt et al., 2011), we considered the criteria heterogeneity, risk of bias and precision where appropriate when reporting the effects of interventions below.

Effects of interventions

Figure 3 provides a graphical overview of which outcomes were measured by which studies and whether or not the interventions had a significant effect on the outcome measures. The full report of intervention effects can be found in Table 2, and details on how outcomes were defined in each study can be found in Appendix 6.

Table 2.

Summary of findings

Universal school-based interventions targeting the general population
	Author(s) (year)	Intervention description	Outcomes studied and effect sizes*
			Knowledge	Attitudes	Intensions	Help-seeking	Action taken	Accessing care	Health outcomes
1	Aseltine et al. (2007)	Two-part suicide prevention program: (1) curriculum via video with dramatisations, interviews and guidelines including discussion guide over half of the school year; (2) screening on depression and suicidality symptoms				OR: 0.96 (0.82–1.12)		OR: 0.99 (0.78–1.25)	OR: 0.84 (0.69–1.02)
2	Campos et al. (2018)	Interactive two-session educational curriculum that explored students' knowledge and beliefs about physical and mental health and illness, identified risk factors and symptoms of mental disorders as well as help-seeking options, promoted non-stigmatised behaviours and inadequate beliefs related to mental disorders and addressed self-help strategies and mental health-promoting behaviour	ES: −0.06 (−0.26–0.14)
3	Hart et al. (2018)	Three standardised pyschoeducation sessions via program booklet, presentations, videos, role-plays, group and workbook activities and final certificate for peer training to help adolescents with a mental health problem	ES: 0.35 (0.23–0.47)	ES: 0.27 (0.15–0.38)		ES: 0.68 (0.56–0.80)
4	Howard et al. (2018)	Two brief online educational interventions consisting of one page of a vignette about a person with depression: a biological condition describing the biological causes of depression and a psychosocial condition describing the psychosocial causes of depression			Biological intervention ES: 0.25 (−0.26–0.76) Psychosocial intervention ES: 0.30 (−0.26–0.85)
5	Husky et al. (2011)	Brief, two-stage mental health screening via questionnaire and structured interview; referrals to mental health care were provided for those who screened positive				OR: 21.64 (6.66–70.36)		OR: 11.34 (3.41–37.69)
6	Jorm et al. (2010)	Two day-long teacher training sessions on common mental health disorders, school policy on mental health issues and how to assist students in need	ES: 0.36 (0.14–0.58)a	OR: 2.56 (1.44–4.57)a		OR: 1.27 (0.89–1.79)b	OR: 1.30 (0.82–2.08)a		OR: 1.08 (0.78–1.51)
7	Klingman and Hochdorf (1993)	Twelve weekly sessions delivering an educational curriculum on mental distress and disorders, help-seeking and prevention via theoretical component, role-playing and rehearsing new skills	ES: 0.96 (0.48–1.43)
8	Morgan et al. (2019)	A 14-h standardised pyschoeducation and training program for parents of adolescents to learn to recognise early signs of a mental health problem or crisis and to assist adolescents to access appropriate professional help as early as possible		ES: 0.23 (−0.06–0.53)b	ES: −0.15 (−0.48–0.18)b	OR: 4.52 (0.57–35.75)	ES: 0.16 (−0.41–0.73)b		OR: 0.62 (0.16–2.34)
9	Painter et al. (2017)	Three-hour educational curriculum on stigma, mental illness and barriers to help-seeking via presentation, class discussion and video and presentation and discussion with a mentally ill college student	ES: 0.31 (0.09–0.53)	ES: 0.42 (0.20–0.65)
10	Perry et al. (2014)	10 h of educational curriculum delivered over 5–8 weeks; resources for teachers delivering intervention included a booklet, slideshow and appendices on mental health, mood disorders and on helping others and oneself		ES: −0.02 (−0.29–0.26)					ES: −0.07 (−0.35–0.20)
11	Saporito et al. (2011)	A 35-min presentation on mental illness and its treatment plus video on an adolescent with a mental illness		ES: 0.71 (0.39–1.04)					ES: −0.31 (−0.63–0.00)
12	Sayal et al. (2010)	School-based screening to identify children with high ADHD rating scale scores and a book about ADHD and how to manage and work with affected children						OR: 1.22 (0.61–2.46)	OR: 1.12 (0.60–2.08)
13	Sharpe et al. (2017)	Booklets on mental health and disorders and help-seeking for students				ES: −0.02 (−0.01–0.05)c			ES: 0.01 (−0.03–0.04)c

Teacher.

Parent.

Estimate for older age group (12–13 years).

Among the studies on universal school-based interventions targeting the general population, 80% (4/5) of those that assessed knowledge about accessing mental health care, 67% (4/6) of those that assessed attitudes or beliefs about seeking care, 22% (2/9) of those that assessed help-seeking or intentions, 20% (1/5) of those that assessed accessing care or taking action and none (0/7) of those that assessed mental health outcomes had a significant impact on the respective outcome. Thus, universal school-based interventions targeting individuals from the general population tended to have a significant impact on steps earlier on the pathway to accessing care, especially knowledge and attitudes, but not on later steps, such as actually accessing care or mental health outcomes. The risk of bias for studies on these interventions ranged from low to high (see Table 1). The effect sizes ranged from −0.06 to 0.96 for knowledge about seeking health care, −0.02 to 2.56 for attitudes about seeking health care and −0.15 to 0.30 for intensions to seek health care or help others seek health care. Both odds ratios and effect sizes were calculated for the outcomes help-seeking, action taken and health outcomes. The odds ratios ranged from 0.96 to 21.64 for help-seeking, 0.99 to 11.34 for accessing care and 0.62 to 1.12 for health outcomes.

The pattern of significant outcomes found for universal interventions differed from that observed for interventions targeting at-risk individuals who had already been identified by the health-care system. Among studies on these interventions, all assessed accessing care (e.g., the proportion of study subjects who attended the first appointment or number of appointments attended) as an outcome, and 71% (15/21) of these interventions had a significant impact on that outcome. Eighty per cent (8/10) of studies on treatment engagement interventions (e.g., a family-based session to increase motivation during an emergency room or motivational telephone calls with trained staff) and 80% (4/5) of studies on appointment reminder interventions had a significant effect on accessing care. Just three interventions targeting at-risk individuals assessed outcomes that preceded accessing care. The effects on knowledge about accessing mental health care, attitudes or beliefs about seeking care and help-seeking were thus unclear due to the limited number of studies measuring these outcomes. Of the seven interventions that assessed the remaining two outcomes along the pathway to accessing care, 33% (2/6) of those that assessed mental health outcomes and 80% (4/5) of those that assessed satisfaction with care were significantly better as compared with controls on the respective outcome. Interventions targeting at-risk children who had already been identified by the health-care system therefore generally yielded more access to care and satisfaction with care as compared with controls, but not necessarily improved mental health outcomes. The risk of bias found for appointment reminder and treatment engagement interventions ranged from low to high (see Table 1). The most important outcome comparisons for these types of interventions are summarised in the meta-analyses below.

Meta-analyses

We conducted meta-analyses for two types of interventions that measured the same outcome (accessing care) using the binary measure first appointment attendance (yes/no): (1) appointment reminder interventions (five studies) and (2) treatment engagement interventions (10 studies). For the appointment reminder interventions, we only calculated a fixed-effects model since heterogeneity was low (I2 = 0%). For the treatment engagement interventions, heterogeneity was substantial (I2 = 70%), so we calculated fixed effects and random-effects models. Forest plots for each of these two types of interventions can be found in Fig. 4. The combined odds ratio of the appointment reminder interventions was 3.11 (2.07–4.67), and the combined odds ratio calculated using the random-effects model for the treatment engagement interventions was 3.51 (2.02–6.11). In other words, the odds of attending an initial appointment were 3.11 times higher for those who received an appointment reminder as compared with controls and 3.51 higher for those who participated in a treatment engagement intervention as compared with controls, indicating that overall, both types of interventions yielded significantly higher first appointment attendance in the target population as compared with controls.

Fig. 4.

Forest plots of appointment reminder and treatment engagement interventions measuring first appointment attendance.

Discussion

Summary of main results

This systematic review identified 34 RCTs of interventions that fell into two main categories: universal school-based interventions targeting the general population and interventions to engage at-risk individuals who had already been identified by the health-care system. Interventions in the first category generally yielded significantly better knowledge and attitudes about accessing care as compared with controls, but did not have an impact on actually accessing care or on mental health outcomes. Most interventions targeting at-risk children who had already been identified by the health-care system yielded significantly better access to care and satisfaction with care as compared with controls, but did not seem to have a significant impact on mental health outcomes. Meta-analyses of appointment reminder interventions and treatment engagement interventions measuring the outcome accessing care using the binary measure first appointment attendance found that both types of interventions yielded significantly more access to care as compared with controls. We did not identify studies that targeted the domains of acceptability and affordability or individuals' ability to reach or pay for care.

Comparison with other reviews

In our study, we used Levesque et al.'s conceptual framework of access to health care to design a systematic review of RCTs of interventions to improve access to mental health care for children (Levesque et al., 2013). This approach enabled us to provide a broad overview of RCTs of interventions that was not limited to particular types of interventions or disorders by structuring our findings along the entire pathway to accessing care. Our results on the effects of universal interventions targeting individuals from the general population were similar to those from a previous systematic review on help-seeking interventions for depression, anxiety and general psychological distress in adults that found that mental health literacy content significantly improved help-seeking attitudes, but did not have an effect on help-seeking behaviour (Gulliver et al., 2012). Another systematic review on interventions to promote help-seeking for mental health problems found that interventions increased formal help-seeking behaviours when targeting affected or at-risk people with mental disorders, but not the general population (Xu et al., 2018). This is the same pattern that we found for the outcome of accessing care.

Strengths and limitations

This systematic review provided an overview of interventions to improve access to mental health care along the entire pathway to accessing care using a conceptual framework, which allowed us to assess where evidence for effective interventions lies and where evidence is missing. However, taking a broad approach to the search necessitated restricting the search to the title field and English language only. We attempted to address this by hand searching reference lists and key articles. In addition, we did not include retention in treatment as an outcome in this review since we were interested in gaining access to treatment.

Implications for practice and research

Both the results of this systematic review and previous research have shown that interventions can improve knowledge and attitudes about mental disorders and their treatment (Lo et al., 2017); however, there is evidence that such interventions do not necessarily have an impact on health behaviours, such as help-seeking (Kelly and Barker, 2016; Laverack, 2017). Interventions to engage and motivate an at-risk population, on the other hand, have been shown to significantly change health behaviours (Ingoldsby, 2010). From a public health perspective, the problem with this finding is that existing interventions do not improve access to care for people in need from the general population, leaving a large treatment gap.

In order to have a population-level effect on improving access to care, it may be necessary to introduce two-stage interventions, i.e., ones that first identify those in need from the general population and then engage them in the health-care system. In this systematic review, the only study in that targeted the general population, yet had a significant impact on accessing care was Husky et al. (2011), which tested systematic referral to mental health services using a brief mental health screening in a school setting (Husky et al., 2011). Additionally, five of the six studies targeting at-risk children that took place in a primary care setting used a screening procedure to identify these at-risk children; however, only two of these five studies had a significant effect on access to care as compared with controls. Since the evidence to recommend screening the general population of children for mental disorders is currently insufficient (Lenzer, 2017), it is imperative to rigorously test screening procedures using RCTs giving careful consideration to the benefits and harms that would result from such screenings (Wissow et al., 2013).

There is growing evidence that changing environmental factors, including policies, infrastructure and health-care financing (Hodgkinson et al., 2017; So et al., 2019), can have a larger impact on health behaviours such as help-seeking than health literacy education (Kelly and Barker, 2016). Integrating mental health services into existing service settings is considered a promising means of improving access to care (Anderson et al., 2017; Hodgkinson et al., 2017; Richardson et al., 2017); however, we identified just one infrastructural intervention that involved providing onsite mental health services for primary care patients (Lieberman et al., 2006). In light of this and the fact that our systematic review revealed gaps in the research on interventions to improve acceptability, affordability and individuals' ability to reach and pay, it seems that more research on interventions that address contextual factors such as these is warranted, although it may be difficult to test some of these interventions via RCT. In addition, targeting individual barriers in isolation, such as cost or insurance coverage, without addressing other barriers like accessibility, acceptability and availability may not improve service utilisation (So et al., 2019). It is possible that interventions that address multiple barriers simultaneously are more likely to have a population-level effect on improving children's access to mental health care, but this must be tested in future research.

Future studies on interventions to improve access to mental health care for young people should attempt to coordinate and standardise the outcomes assessed so that more quantitative comparison among studies via meta-analysis is possible. We especially need more studies testing the effects on mental health care outcomes since this is the ultimate purpose of improving access to care. In addition, longer follow-up periods are required to gain information about the longer-term effects of interventions to improve access to care (Salerno, 2016; Anderson et al., 2017). Finally, none of the studies identified in this systematic review took place in low- or middle-income countries. Due to a shortage of mental health professionals, the fact that detection rates of mental disorders are much lower in many of these countries, less developed infrastructure and potentially more stigma surrounding mental health disorders, different interventions than those that are effective in high-income countries may be required (Patel et al., 2013). More research is therefore needed to draw conclusions about improving access to care in these settings.

Conclusion

In order to bridge the existing treatment gap in mental health care for children, interventions that aim to improve knowledge and attitudes about mental health care in the general population are not sufficient. Instead, a two-stage approach that first identifies young people in need of care from the general population and then engages them in the health-care system should be tested in high quality studies. In addition, we need high quality research on the impact of interventions addressing contextual factors such as affordability and individuals' ability to reach care.

Interventions to engage at-risk individuals in health-care system
	Author(s) (year)	Intervention description	Outcomes studied and effect sizes*
			Knowledge	Attitudes	Help-seeking	Accessing care	Health outcomes	Satisfaction
14	Asarnow et al. (2005)	6-month health service quality improvement intervention through support and training for clinicians on treatment for people with mental disorders by expert leader teams and care managers				OR: 2.17 (1.31–3.62)	ES: −0.25 (−0.46–0.03)	ES: 0.32 (0.10–0.53)1
15	Asarnow et al. (2011)	Brief family-based therapy session to increase motivation during emergency room visit by reframing the problem, educating families about the importance of treatment, obtaining commitment from youth, identifying triggers, and developing and practising a safety plan supplemented by care linkage telephone contacts within the first 48 h after discharge				OR: 3.65 (1.38–9.65)	OR: 0.88 (0.23–3.40)
16	Coker et al. (2019)	A 5-min video on community mental health clinic and scheduled visit for a telehealth eligibility screening				OR: 0.80 (0.40–1.62)	ES: −0.01 (−0.24–0.23)	ES: 0.40 (0.17–0.64)
17	Donohue et al. (1998)	Telephone call by clinical psychology doctoral students to parents about treatment, intake session for parent and youth, motivational reminder calls, and incentives to participate in treatment				OR: 5.67 (1.02–31.54)
18	Fristad et al. (2003)	Didactic and interactive multi-family psycho-education group program; parent sessions focused on providing social support, information and skills, while child sessions focused on feeling less alone, understanding symptoms and effects of treatment and building social skills		ES: 1.30 (0.45–2.16)		OR: 18.00 (2.47–131.29)	Not reported
19	Gadomski et al. (2010)	Three hour-long communication skills training sessions for primary care clinicians to engage parents and children in diagnosis and treatment and address barriers to treatment with group discussions and 10-min practice visits				ES: −0.03 (−0.23–0.16)
20	Grupp-Phelan et al. (2012)	Discussion with a study social worker about screening results, patient concerns and available resources; designed to target various barriers and increase motivation for help-seeking behaviour			OR: 2.33 (0.42–43.20)	OR: 9.62 (1.38–67.25)	ES: 0.73 (−0.10–1.56)	OR: 48.0 (3.70–622.0)
21	Gully et al. (2008)	Educational booklet for parents on expectations and perceived value of treatment reviewed together with nurses	ES: 2.18 (1.49–2.88)	ES: 0.06 (−0.49–0.61)		ES: 1.46 (0.84–2.07)		ES: 0.90 (0.32–1.47)
22	Kourany et al. (1990)	Reminder telephone call, letter describing what would happen on the first clinic visit or both the call and the letter				OR: 3.56 (1.28–9.94)
23	Lieberman et al. (2006)	Provision of on-site mental health services (usual care was a referral to an off-site mental health provider)				OR: 74.0 (8.94–612.84)
24	MacLean et al. (1989)	One of four experimental letters (systematic appointment reminders, change slips requesting if appointment time should be changed, warnings and change slips combined with warnings)				OR: 3.64 (1.40–9.48)
25	McKay et al. (1996a)	Intensive 30-min telephone intervention with a social worker to engage caretaker in help-seeking process by identifying child's problem, framing caretaker actions as having potential to impact the situation and exploring barriers to help-seeking				OR: 3.22 (1.44–7.19)
26	McKay et al. (1996b)	Telephone intake with therapists trained in specific engagement skills, i.e., informing clients about the process of obtaining mental health services, responding to concrete concerns or crisis situations and exploring potential barriers to obtaining services				OR: 4.16 (1.32–13.12)
27	McKay et al. (1998)	Thirty-minute telephone and in-person engagement intervention by master's level clinicians to clarify the need for mental health care, increase the caretaker's investment in help-seeking, identify attitudes about and previous experiences with mental health care and over concrete barriers to accessing services				OR: 8.77 (3.41–22.54)
28	Parrish et al. (1986)	Letter informing parents that children would be moved to the bottom of the waiting list if three appointments were missed or letter informing parents that attending appointments would earn a coupon for winning a prize				OR: 3.36 (1.40–8.03)
29	Planos and Glenwich (1986)	Appointment reminder (telephone or letter prompt)				OR: 3.06 (1.33–7.05)
30	Richardson et al. (2014)	A 12-month collaborative care intervention delivered by master's-level clinicians involving initial in-person education engagement session, choice of treatment and regular follow-up				OR: 1.03 (0.42–2.51)	ES: −0.57 (−1.02– −0.12)	OR: 2.1 (0.7–6.1)
31	Stern et al. (2015)	A 10–15 min enhanced engagement phone intake to develop rapport with parents, identify and address likely barriers to treatment, increase parental self-efficacy, hope and treatment motivation				OR: 2.30 (0.97–5.46)
32	Stevens et al. (2009)	Three phone calls in the first weeks after the first visit to the adolescent management clinic to assess youth's understanding of recommendations, address youth's struggles through case management and use motivational interviewing techniques if youth was ambivalent about treatment				OR: 1.10 (0.51–2.38)
33	Szapocznik et al. (1988)	Engagement intervention during intake interview to overcome family's resistance to treatment by identifying family patterns that interfere with entry into treatment				OR: 17.73 (5.58–56.34)	ES: −0.62 (−1.01– −0.24)
34	Wiseman and McBride (1998)	A letter stating that confirmation from parents was required if they still wanted an appointment				OR: 2.30 (0.94–5.61)

ES, effect size; OR, odds ratio.

Significant/not significant at 95% confidence level.

Section/topic	#	Checklist item	Reported on page #
Title
Title	1	Identify the report as a systematic review, meta-analysis or both.	1
Abstract
Structured summary	2	Provide a structured summary including as applicable: background; objectives; data sources; study eligibility criteria, participants and interventions; study appraisal and synthesis methods; results; limitations; conclusions and implications of key findings; systematic review registration number.	1
Introduction
Rationale	3	Describe the rationale for the review in the context of what is already known.	1–2
Objectives	4	Provide an explicit statement of questions being addressed with reference to participants, interventions, comparisons, outcomes and study design (PICOS).	2
Methods
Protocol and registration	5	Indicate if a review protocol exists, if and where it can be accessed (e.g., Web address) and, if available, provide registration information including registration number.	2
Eligibility criteria	6	Specify study characteristics (e.g., PICOS, length of follow-up) and report characteristics (e.g., years considered, language, publication status) used as criteria for eligibility, giving rationale.	2
Information sources	7	Describe all information sources (e.g., databases with dates of coverage, contact with study authors to identify additional studies) in the search and date last searched.	2
Search	8	Present full electronic search strategy for at least one database, including any limits used, such that it could be repeated.	Appendix 3
Study selection	9	State the process for selecting studies (i.e., screening, eligibility, included in systematic review and, if applicable, included in the meta-analysis).	2–3
Data collection process	10	Describe the method of data extraction from reports (e.g., piloted forms, independently, in duplicate) and any processes for obtaining and confirming data from investigators.	2–3
Data items	11	List and define all variables for which data were sought (e.g., PICOS, funding sources) and any assumptions and simplifications made.	2
Risk of bias in individual studies	12	Describe methods used for assessing risk of bias of individual studies (including specification of whether this was done at the study or outcome level), and how this information is to be used in any data synthesis.	3, 5
Summary measures	13	State the principal summary measures (e.g., risk ratio, difference in means).	3–4
Synthesis of results	14	Describe the methods of handling data and combining results of studies, if done, including measures of consistency (e.g., I2) for each meta-analysis.	3–4
Risk of bias across studies	15	Specify any assessment of risk of bias that may affect the cumulative evidence (e.g., publication bias, selective reporting within studies).	N/A
Additional analyses	16	Describe methods of additional analyses (e.g., sensitivity or subgroup analyses, meta-regression), if done, indicating which were pre-specified.	3–4
Results
Study selection	17	Give numbers of studies screened, assessed for eligibility and included in the review, with reasons for exclusions at each stage, ideally with a flow diagram.	4–5, Fig. 1
Study characteristics	18	For each study, present characteristics for which data were extracted (e.g., study size, PICOS, follow-up period) and provide the citations.	4–5, Table 2, Appendix 5
Risk of bias within studies	19	Present data on risk of bias of each study and, if available, any outcome level assessment (see item 12).	5, Table 1
Results of individual studies	20	For all outcomes considered (benefits or harms), present, for each study: (a) simple summary data for each intervention group (b) effect estimates and confidence intervals, ideally with a forest plot.	Table 2, Fig. 4
Synthesis of results	21	Present results of each meta-analysis done, including confidence intervals and measures of consistency.	7
Risk of bias across studies	22	Present results of any assessment of risk of bias across studies (see Item 15).	N/A
Additional analysis	23	Give results of additional analyses, if done (e.g., sensitivity or subgroup analyses, meta-regression [see Item 16]).	Figures 2 and 3
Discussion
Summary of evidence	24	Summarise the main findings including the strength of evidence for each main outcome; consider their relevance to key groups (e.g., healthcare providers, users and policymakers).	7–12
Limitations	25	Discuss limitations at study and outcome level (e.g., risk of bias), and at review-level (e.g., incomplete retrieval of identified research, reporting bias).	8
Conclusions	26	Provide a general interpretation of the results in the context of other evidence and implications for future research.	7–12
Funding
Funding	27	Describe sources of funding for the systematic review and other support (e.g., supply of data); role of funders for the systematic review.	N/A

Search in EMBASE Date of search: 15 May 2019
No.	Query	Results
# 1	‘mental disease'/exp OR 'mental health’/exp OR (((mental OR mentally OR psychiatric OR psychological OR psychosocial OR behavioural OR behavioural OR emotional) NEAR/3 (health OR disease OR diseases OR disorder OR disorders OR ill OR illness OR illnesses OR insanity OR insanities OR abnormality OR abnormalities OR disturbance OR disturbances OR confusion OR confusions OR symptom OR symptoms OR health OR problem OR problems)):ti) OR depression:ti OR depressive:ti	2269428
# 2	‘adolescent’/exp OR ‘child’/exp OR child:ti OR children:ti OR adolescent:ti OR adolescents:ti OR juvenile:ti OR juveniles:ti OR young:ti OR youth:ti OR pediatric*:ti OR paediatric*:ti OR teen*:ti OR ‘young people’:ti OR ‘young person*’:ti OR minor*:ti	3820655
# 3	‘help seeking behavior’/exp OR (((help OR treatment OR treatments) NEAR/5 (seek* OR behavior OR behaviour)):ti) OR helpseeking:ti OR ‘mental health literacy’:ti OR (((screening* OR intervention* OR communica* OR utili?ation OR access OR attitude*) NEAR/5 (mental OR psych*)):ti)	31782
# 4	#1 AND #2 AND #3	4583
# 5	#1 AND #2 AND #3 NOT ([animals]/lim NOT [humans]/lim) AND [english]/lim NOT [conference abstract]/lim	3676

Note: This search strategy was adapted to search MEDLINE, PsycINFO and the Cochrane Central Register of Controlled Trials (CENTRAL)

Universal school-based interventions targeting the general population
No.	First author, year/country	N enrolled/analysed	Age	Setting	Targeted population	Target condition	Intervention description	Intervention duration	Assessment time point(s)	Outcomes studied
1	Aseltine, 2007/USA	4491/3837–3899	14–18	School	Students	Suicide	Two-part suicide prevention program: (1) curriculum via video with dramatisations, interviews and guidelines including discussion guide over half of the school year; (2) screening on depression and suicidality symptoms	2 days	3 months	– Help-seeking – Accessing care – Health outcomes
2	Campos, 2018/Portugal	543/387	12–14	School	Students	General mental health problems	Interactive two-session educational curriculum that explored students' knowledge and beliefs about physical and mental health and illness, identified risk factors and symptoms of mental disorders as well as help-seeking options, promoted non-stigmatised behaviours and inadequate beliefs related to mental disorders and addressed self-help strategies and mental health-promoting behaviour	Two 90-min sessions (1 week apart)	– 1 week (post-intervention) – 6 months	Knowledge
3	Hart, 2018/Australia	1942/1116	15–18	School	Student peers, parents and teachers	General mental health problems	Three standardised pyschoeducation sessions via program booklet, presentations, videos, role-plays, group and workbook activities and final certificate for peer training to help adolescents with a mental health problem	3 weeks	1 week	– Knowledge – Attitudes – Intentions
4	Howard, 2018/Australia	350/327	16–19	School	Students	Depression	Two brief online educational interventions consisting of one page of a vignette about a person with depression: a biological condition describing the biological causes of depression and a psychosocial condition describing the psychosocial causes of depression	Single time point	Directly post-intervention	Intensions
5	Husky, 2011/USA	890/656	14–15	School	Students	General mental health problems	Brief, two-stage mental health screening via questionnaire and structured interview; referrals to mental health care were provided for those who screened positive	Single time point	3–5 months	– Help-seeking – Accessing care
6	Jorm, 2010/Australia	423/327	12–15	School	Teachers	General mental health problems	Two day-long teacher training sessions on common mental health disorders, school policy on mental health issues and how to assist students in need	Two days	– Directly post-intervention – 6 months	– Knowledge – Attitudes – Intentions – Action taken – Health outcomes
7	Klingman, 1993/Israel	237/76	12–13	School	Student peers	Mental distress and suicide	Twelve weekly sessions delivering an educational curriculum on mental distress and disorders, help-seeking and prevention via theoretical component, role-playing and rehearsing new skills	12 weeks	2 weeks	Knowledge
8	Morgan, 2019/Australia	384/322	12–15	School	Parents of adolescents	General mental health problems	A 14-h standardised pyschoeducation and training program for parents of adolescents to learn to recognise early signs of a mental health problem or crisis and to assist adolescents to access appropriate professional help as early as possible	Two sessions over four months	– 1 year – 2 years	– Attitudes – Intensions – Action taken – Help-seeking – Health outcomes
9	Painter, 2017/USA	751/721	10–13	School	Students	General mental health problems	Three-hour educational curriculum on stigma, mental illness and barriers to help-seeking via presentation, class discussion and video and presentation and discussion with a mentally ill college student	⩽1 week	1 week	– Knowledge – Attitudes
10	Perry, 2014/Australia	380/208	13–16	School	Students	General mental health problems	Ten hour of educational curriculum delivered over 5–8 weeks; resources for teachers delivering intervention included a booklet, slideshow and appendices on mental health, mood disorders and on helping others and oneself	5–8 weeks	– Post-intervention – 6 months	– Attitudes – Health outcomes
11	Saporito, 2011/USA	159/156	15–19	School	Students	General mental health problems	A35-min presentation on mental illness and its treatment plus video on an adolescent with a mental illness	Single time point	Directly post-intervention	– Attitudes – Health outcomes
12	Sayal, 2010/UK	1662/487	4–5	School	Students and teachers	Attention-deficit hyperactivity disorder	School-based screening to identify children with high ADHD rating scale scores and a book about ADHD and how to manage and work with affected children	Single time point	5 years	– Accessing care – Health outcomes
13	Sharpe, 2017/UK	27▫885/ 14▫690	10–13	School	Students	General mental health problems	Booklets on mental health and disorders and help-seeking for students	Single time point	12 months	– Help-seeking – Health outcomes

Interventions to engage at-risk individuals within health-care system
No.	First author, year/country	N enrolled/analysed	Age	Setting	Targeted population	Target condition	Intervention description	Intervention duration	Assessment time point(s)	Outcomes studied
14	Asarnow, 2005/USA	418/344	13–21	Primary care	Patients with depressive symptoms and their parents (when appropriate)	Depression	6-month health service quality improvement intervention through support and training for clinicians on treatment for people with mental disorders by expert leader teams and care managers	6 months	6 months	– Accessing care – Health outcomes – Satisfaction
15	Asarnow, 2011/USA	181/160	10–18	Emergency department	Suicidal youths and their families	Suicide	Brief family-based therapy session to increase motivation during emergency room visit by reframing the problem, educating families about the importance of treatment, obtaining commitment from youth, identifying triggers and developing and practising a safety plan supplemented by care linkage telephone contacts within the first 48 h after discharge	Single time point with follow-up phone calls after 48 h and additional contacts as needed (usually 1, 2 and 4 weeks post-discharge)	2 months	– Accessing care – Health outcomes
16	Coker, 2019/USA	342/342	5–12	Primary care	Parents of children referred to community mental health clinics	General mental health problems	A 5-min video on community mental health clinic and scheduled visit for a telehealth eligibility screening	Single time point	6 months	– Accessing care – Health outcomes – Satisfaction
17	Donohue, 1998/USA	39/39	Not stated (ca. 12–18)	Outpatient cognitive-behavioural treatment program specialising in adolescent substance dependence and conduct disorder	Adolescents referred as prospective clients and their parents	Conduct disorder and substance abuse	Telephone call by clinical psychology doctoral students to parents about treatment, intake session for parent and youth, motivational reminder calls and incentives to participate in treatment	Single time point	Directly post-intervention	Accessing care
18	Fristad, 2003/USA	52/42	8–11	Clinical research group	Children with mood disorders and their parents	Mood disorders	Didactic and interactive multi-family psycho-education group program; parent sessions focused on providing social support, information and skills, while child sessions focused on feeling less alone, understanding symptoms and effects of treatment and building social skills	6 sessions over 6 weeks	– 2 months – 6 months	– Attitudes – Accessing care – Health outcomes
19	Gadomski, 2010/USA	397/397	5–16	Primary care	Primary care providers who treat children with possible or probable mental health problems	General mental health problems	Three hour-long communication skills training sessions for primary care clinicians to engage parents and children in diagnosis and treatment and address barriers to treatment with group discussions and 10-min practice visits	Single time point	– 2 weeks – 3 months – 6 months	Accessing care
20	Grupp-Phelan, 2012/USA	24/24	12–17	Emergency department	Patients with suicide-related risk factors	Suicide	Discussion with a study social worker about screening results, patient concerns and available resources; designed to target various barriers and increase motivation for help-seeking behaviour	Single time point	2 months	– Help-seeking – Accessing care – Health outcomes – Satisfaction
21	Gully, 2008/USA	87/51	2–17	Child advocacy centres and outpatient program at hospital	Parents of children who are suspected victims of abuse	General mental health problems	Educational booklet for parents on expectations and perceived value of treatment reviewed together with nurses	Single time point	1 month	– Knowledge – Attitudes – Accessing care – Satisfaction
22	Kourany, 1989/USA	111/111	2–17	Outpatient child psychiatry clinic	Parents of prospective clients	General mental health problems	Reminder telephone call, letter describing what would happen on the first clinic visit, or both the call and the letter	Single time point	Directly post-intervention	Accessing care
23	Lieberman, 2006/USA	71/71	13–22	Primary care	Adolescents with psychosocial issues	General mental health problems	Provision of on-site mental health services (usual care was a referral to an off-site mental health provider)	Single time point	3 months	Accessing care
24	MacLean, 1989/Canada	327/327	<12	Child community mental health centre	Parents of prospective clients	Non-emergency general mental health problems	One of four experimental letters (systematic appointment reminders, change slips requesting if appointment time should be changed, warnings and change slips combined with warnings)	Single time point	Directly post-intervention	Accessing care
25	McKay, 1996a/USA	108/108	Not stated	Child mental health agency	Caretakers requesting mental health services	General mental health problems	Intensive 30-min telephone intervention with a social worker to engage caretaker in help-seeking process by identifying child's problem, framing caretaker actions as having potential to impact the situation, and exploring barriers to help-seeking	Single time point	Directly post-intervention	Accessing care
26	McKay, 1996b/USA	107/107	Not stated	Urban child mental health agency	Parents of prospective clients	Non-emergency general mental health problems	Telephone intake with therapists trained in specific engagement skills, i.e., informing clients about the process of obtaining mental health services, responding to concrete concerns or crisis situations and exploring potential barriers to obtaining services	Single time point	Directly post-intervention	Accessing care
27	McKay, 1998/USA	109/109	1–14	Child mental health agency	Caregivers of urban children who requested services at the mental health agency	General mental health problems	Thirty-minute telephone and in-person engagement intervention by master's level clinicians to clarify the need for mental health care, increase the caretaker's investment in help-seeking, identify attitudes about and previous experiences with mental health care, and over concrete barriers to accessing services	Single time point	18 weeks	Accessing care
28	Parrish, 1986/USA	99/99	2–20	Outpatient behavioural paediatrics clinic	Parents of children referred as prospective clients	Behavioural health problems	Letter informing parents that children would be moved to the bottom of the waiting list if three appointments were missed or letter informing parents that attending appointments would earn a coupon for winning a prize	Single time point	Directly post-intervention	Accessing care
29	Planos, 1986/USA	274/274	<18	Children's mental health centre	Parents of children referred as prospective clients	General mental health problems	Appointment reminder (telephone or letter prompt)	Single time point	1 month	Accessing care
30	Richardson, 2014/USA	101/101	13–17	Primary care	Adolescents who screened positive for depression and their parents	Depression	A 12-month collaborative care intervention delivered by master's-level clinicians involving initial in-person education engagement session, choice of treatment and regular follow-up	12 months	12 months	– Accessing care – Health outcomes – Satisfaction
31	Stern, 2015/Canada	117/99	5–12	Children's mental health centre	Parents of children with mental health problems	General mental health problems	A 10–15 min enhanced engagement phone intake to develop rapport with parents, identify and address likely barriers to treatment, increase parental self-efficacy, hope and treatment motivation	Single time point	Not standardised – several weeks to months	Accessing care
32	Stevens, 2009/USA	179/179	11–20	Primary care	Adolescents who screened positive for at least one of depressive symptoms, suicidal ideation or substance abuse	Depression, suicide and substance abuse	Three phone calls in the first weeks after the first visit to the adolescent management clinic to assess youth's understanding of recommendations, address youth's struggles through case management and use motivational interviewing techniques if youth was ambivalent about treatment	Several weeks to months	6 months	Accessing care
33	Szapocznik, 1988/USA	108/108	12–21	Mental health centre	Adolescent drug abusers and their families	Substance abuse	Engagement intervention during intake interview to overcome family's resistance to treatment by identifying family patterns that interfere with entry into treatment	As many contacts as necessary within 3-week period	3 weeks	– Accessing care – Health outcomes
34	Wiseman, 1998/UK	128/128	Not stated	Child mental health clinic	Parents of prospective clients	Non-emergency general mental health problems	Didactic and interactive multi-family psycho-education group program; parent sessions focused on providing social support, information, skills, while children sessions focused on feeling less alone, understanding symptoms and effects of treatment, and building social skills	Single time point	Directly post-intervention	Accessing care

Universal school-based interventions targeting the general population
	First author (year)	Intervention description	Outcomes studied
			Knowledge	Attitudes	Intensions	Help-seeking	Action taken	Accessing care	Health outcomes
1	Aseltine (2007)	Two-part suicide prevention program: (1) curriculum via video with dramatisations, interviews and guidelines including discussion guide over half of the school year; (2) screening on depression and suicidality symptoms				Talking to an adult due to feeling depressed or suicidal		Receiving specialist care	Suicidal ideation (suicide attempts also measured as an outcome)
2	Campos (2018)	Interactive two-session educational curriculum that explored students' knowledge and beliefs about physical and mental health and illness, identified risk factors and symptoms of mental disorders as well as help-seeking options, promoted non-stigmatised behaviours and inadequate beliefs related to mental disorders and addressed self-help strategies and mental health-promoting behaviour	Knowledge about first aid skills and help-seeking
3	Hart (2018)	Three standardised pyschoeducation sessions via program booklet, presentations, videos, role-plays, group and workbook activities, and final certificate for peer training to help adolescents with a mental health problem	Knowledge about when to recommend that another person seek help	Confidence in supporting a peer	Endorsing intentions to help a peer to seek help
4	Howard (2018)	Two brief online educational interventions consisting of one page of a vignette about a person with depression: a biological condition describing the biological causes of depression and a psychosocial condition describing the psychosocial causes of depression			Help-seeking intentions
5	Husky (2011)	Brief, two-stage mental health screening via questionnaire and structured interview; referrals to mental health care were provided for those who screened positive				Any student assistance contact		Any access to community-based services (any access to school-based services also measured)
6	Jorm (2010)	Two day-long teacher training sessions on common mental health disorders, school policy on mental health issues and how to assist students in need	Beliefs about treatment for depressiona	Confidence to talk with students about mental health problemsa	Help-seeking intentionsb		Spoke to students about mental health problems occasionally or morea		Mental health (abnormal SDQ score)
7	Klingman (1993)	Twelve weekly sessions delivering an educational curriculum on mental distress and disorders, help-seeking, and prevention via theoretical component, role-playing and rehearsing new skills	Knowledge of facts about help resources
8	Morgan (2019)	A 14-h standardised pyschoeducation and training program for parents of adolescents to learn to recognise early signs of a mental health problem or crisis and to assist adolescents to access appropriate professional help as early as possible		Parental confidence to help adolescentb	Parental intensions to help adolescentb	Help-seeking by adolescent	Quality of parental supportb		Adolescent mental health
9	Painter (2017)	Three-hour educational curriculum on stigma, mental illness and barriers to help-seeking via presentation, class discussion and video and presentation and discussion with a mentally ill college student	Knowledge about when to recommend that another person seek help	Personal willingness to seek help
10	Perry (2014)	A 10 h of educational curriculum delivered over 5–8 weeks; resources for teachers delivering intervention included a booklet, slideshow and appendices on mental health, mood disorders and on helping others and oneself		Explicit attitudes toward seeking help					Psychological distress (suicidal ideation also measured as an outcome)
11	Saporito (2011)	35-min presentation on mental illness and its treatment plus video on an adolescent with a mental illness		Explicit attitudes toward seeking professional help					Emotional health (change in negative affect measured by PANAS)
12	Sayal (2010)	School-based screening to identify children with high ADHD rating scale scores and a book about ADHD and how to manage and work with affected children						Specialist service use	Symptoms of hyperactivity and inattention
13	Sharpe (2017)	Booklets on mental health and disorders and help-seeking for students				Frequency of seeking help from counsellor			Mental health (measured by Me and My School Questionnaire)

Interventions to engage individuals in health-care system
	First author (year)	Intervention description	Outcomes studied
			Knowledge	Attitudes	Help-seeking	Accessing care	Health outcomes	Satisfaction
14	Asarnow (2005)	A 6-month health service quality improvement intervention through support and training for clinicians on treatment for people with mental disorders by expert leader teams and care managers				Proportion of subjects who accessed any speciality mental health care	Depressive symptoms (measured by CES-D)	Satisfaction with mental health care
15	Asarnow (2011)	Brief family-based therapy session to increase motivation during emergency room visit by reframing the problem, educating families about the importance of treatment, obtaining commitment from youth, identifying triggers and developing and practising a safety plan supplemented by care linkage telephone contacts within the first 48 h after discharge				Outpatient mental health treatment	Suicide attempts
16	Coker (2019)	A 5-min video on community mental health clinic and scheduled visit for a telehealth eligibility screening				Community mental health clinic screening visit	Health-related quality of life (measured by the Pediatric Quality of Life Inventory)	Satisfaction with the referral process
17	Donohue (1998)	Telephone call by clinical psychology doctoral students to parents about treatment, intake session for parent and youth, motivational reminder calls and incentives to participate in treatment				Proportion of subjects who attended the first appointment
18	Fristad (2003)	Didactic and interactive multi-family psycho-education group program; parent sessions focused on providing social support, information and skills, while child sessions focused on feeling less alone, understanding symptoms and effects of treatment and building social skills		Perceived social support from parents		Ability to obtain appropriate services	Illness severity (measured by CDRS-R, MRS)
19	Gadomski (2010)	Three hour-long communication skills training sessions for primary care clinicians to engage parents and children in diagnosis and treatment and address barriers to treatment with group discussions and 10-min practice visits				Number of primary care visits
20	Grupp-Phelan (2012)	Discussion with a study social worker about screening results, patient concerns and available resources; designed to target various barriers and increase motivation for help-seeking behaviour			Proportion of subjects who scheduled the first appointment	Proportion of subjects who attended the first appointment	Depressive symptoms (measured by CES-D)	Screening found to be helpful
21	Gully (2008)	Educational booklet for parents on expectations and perceived value of treatment reviewed together with nurses	Knowledge about evidence-based treatment	Belief that evidence-based treatment is helpful		Proportion of subjects who attended the first appointment and discussed evidence-based treatment during appointment		Satisfaction with services
22	Kourany (1989)	Reminder telephone call, letter describing what would happen on the first clinic visit, or both the call and the letter				Proportion of subjects who attended the first appointment
23	Lieberman (2006)	Provision of on-site mental health services (usual care was a referral to an off-site mental health provider)				Meeting with a counsellor at least once
24	MacLean (1989)	One of four experimental letters (systematic appointment reminders, change slips requesting if appointment time should be changed, warnings and change slips combined with warnings)				Proportion of subjects who attended the first appointment
25	McKay (1996a)	Intensive 30-minute telephone intervention with a social worker to engage caretaker in help-seeking process by identifying child's problem, framing caretaker actions as having potential to impact the situation and exploring barriers to help-seeking				Proportion of subjects who attended the first appointment
26	McKay (1996b)	Telephone intake with therapists trained in specific engagement skills, i.e., informing clients about the process of obtaining mental health services, responding to concrete concerns or crisis situations and exploring potential barriers to obtaining services				Proportion of subjects who attended the first appointment
27	McKay (1998)	Thirty-minute telephone and in-person engagement intervention by master's level clinicians to clarify the need for mental health care, increase the caretaker's investment in help-seeking, identify attitudes about and previous experiences with mental health care and over concrete barriers to accessing services				Proportion of subjects who attended the first appointment (proportion of sessions attended v. scheduled was also measured)
28	Parrish (1986)	Letter informing parents that children would be moved to the bottom of the waiting list if three appointments were missed or letter informing parents that attending appointments would earn a coupon for winning a prize				Proportion of subjects who attended the first appointment
29	Planos (1986)	Appointment reminder (telephone or letter prompt)				Proportion of subjects who attended screening appointments
30	Richardson (2014)	A 12-month collaborative care intervention delivered by master's-level clinicians involving initial in-person education engagement session, choice of treatment and regular follow-up				Proportion of subjects with any specialty mental health visits according to administrative data	Depressive symptoms (measured by CDRS-R)	Satisfaction with treatment
31	Stern (2015)	A 10–15 min enhanced engagement phone intake to develop rapport with parents, identify and address likely barriers to treatment, increase parental self-efficacy, hope and treatment motivation				Attendance of first face-to-face interview
32	Stevens (2009)	Three phone calls in the first weeks after the first visit to the adolescent management clinic to assess youth's understanding of recommendations, address youth's struggles through case management and use motivational interviewing techniques if youth was ambivalent about treatment				Any mental health service use
33	Szapocznik (1988)	Engagement intervention during intake interview to overcome family's resistance to treatment by identifying family patterns that interfere with entry into treatment				Proportion of subjects visiting centre for intake appointment	Psychiatric and psychosocial functioning (measured by PSS)
34	Wiseman (1998)	Didactic and interactive multi-family psycho-education group program; parent sessions focused on providing social support, information, skills, while children sessions focused on feeling less alone, understanding symptoms and effects of treatment and building social skills				Proportion of subjects who attended the first appointment

aTeacher.

bParent.