###### Strengths and limitations of this study

-   This is the first randomised controlled trial to examine the Youth Aware of Mental Health and the Mental Health and High School Curriculum Guide compared with the Usual Provision in England.

-   The trial is powered to detect small effects.

-   Both interventions are only compared with the control group, rather than with each other.

-   Only the trial statistician, economist and the individual conducting quantitative analysis are blinded to what intervention each school has been allocated.

Introduction {#s1}
============

Half of presenting mental health difficulties appear before the age of 14, and three-quarters before the age of 24.[@R1] Such instances are associated with poorer physical health outcomes and educational attainment.[@R1] Within the UK, a recent survey of 30 000 young people in schools found that 18.4% reported experiencing high levels of emotional distress.[@R3] The latest prevalence survey suggests that 1 in 8 of 5--19 year-olds have at least one mental health difficulty and that emotional difficulties are increasing in young people.[@R4]

Childhood and adolescence are important developmental phases for prevention and early intervention initiatives for mental health and well-being.[@R5] Seeking help for depressive symptoms at 14 decreases the risk of developing clinical depressive symptoms at 17 sevenfold.[@R7] Prevention and early intervention programmes have demonstrated a good return on investment, with a 6%--10% annual rate of return on investment spent.[@R8] However, young people report barriers to help-seeking, such as difficulty identifying that there is a problem and perceived and internalised stigma.[@R9] Improving help-seeking knowledge and the ability to recognise distress are suggested ways to improve mental health.[@R11]

Schools are often viewed as a universal point of access to children and young people, offering an important opportunity to embed mental health and well-being initiatives.[@R13] Schools can provide a non-stigmatising environment where young people and parents/carers can engage, outside of mental health services,[@R14] and can also present opportunities for pupils to develop self-management strategies.[@R15]

Universal prevention programmes {#s1-1}
-------------------------------

There is growing evidence for the role of school-based promotion and prevention programmes for mental health and well-being. A meta-analysis examining interventions aimed at social and emotional learning demonstrated that pupils who received interventions had significantly improved social and emotional skills, behaviour and academic performance.[@R16] However, impact is often highly dependent on successful implementation; interventions that are implemented well in schools can produce outcomes that are two to three times higher than those implemented poorly.[@R17] Multiple factors can influence implementation at different levels of the system, including policy, provider and intervention characteristics, and factors related to the prevention support system.[@R17] Organisational capacity and the feasibility of delivery within specific contexts are also repeatedly highlighted. Despite this, there is often an expectation that the evidence base for interventions delivered in one context will successfully transfer to other quite different settings. Relatedly, few studies tend to run implementation and process evaluations in parallel with examining effectiveness, and those that do tend to focus on fidelity.[@R18] Examining aspects such as social validity and cultural validity are important, particularly when importing interventions from other countries.[@R19]

Some universal programmes place emphasis on improving individual's mental health literacy. Such interventions traditionally focus on educating and changing beliefs about mental disorders to aid their recognition, management or prevention, and increasingly include mental health first aid.[@R20] Kutcher *et al* recently defined mental health literacy as having four main components, including the addition of mental health promotion: '(1) understanding how to obtain and maintain positive mental health, (2) understanding mental disorders and their treatments, (3) decreasing stigma related to mental disorders and (4) enhancing help-seeking efficacy (knowing when and where to seek help and developing competencies designed to improve one's mental health care and self-management capabilities.'[@R22] The Youth Aware of Mental Health (YAM) is an example of a universal intervention that aims to improve awareness and promote mental health.[@R23] As part of the Saving and Empowering Young Lives in Europe cluster randomised controlled trial, a suicide prevention programme across 12 European countries, YAM was compared with two active interventions, 'Professional screening' and 'Question, Persuade, and Refer', and a control group.[@R24] No difference between arms on suicidal ideation or attempts was found at 3-month follow-up, however YAM significantly reduced the risk of suicide attempts and suicidal ideation at 12-month follow-up compared with the control group.[@R23] Interviews with young people have found they prefer YAM to regular classroom activities, however differences were reported in how actively involved they wanted to be in YAM.[@R25]

The Mental Health and High School Curriculum Guide (The Guide)[@R26] also aims to increase awareness of mental disorders and their treatments, as well as increasing understanding of how to obtain and maintain mental health, reduce stigma and improve help-seeking efficacy. Delivery of The Guide in Canada was found to increase student and staff knowledge, reduce stigma and increase help-seeking in students.[@R26] In Tanzania, The Guide has been shown to increase teacher knowledge and reduce stigma,[@R30] teacher reports also highlighted positive changes to knowledge, attitude and behaviour in their pupils.[@R31] Significantly improved mental health knowledge, reduced stigma, more adaptive coping, better lifestyle choices and lower perceived stress were also found for students who received The Guide in Nicaragua.[@R33]

While YAM and The Guide have a developing evidence base in multiple countries, evidence for the effectiveness of such approaches in the UK is sparse. A scoping exercise conducted by the Department for Education in England concluded that both should be tested to contribute to the UK evidence base for effective interventions to improve mental health in children and young people. As the interventions were developed in other countries, undertaking a process and implementation evaluation to understand factors beyond fidelity and effectiveness is important.[@R19] Thus, alongside this randomised controlled trial examining effectiveness, a process and implementation evaluation will be undertaken to investigate YAM and The Guide compared with Usual Provision in English schools.

Aims and hypothesis {#s1-2}
-------------------

### Effectiveness measurement {#s1-2-1}

Primary aims:

1.  To examine whether YAM is more effective than the usual school-based provision in reducing emotional difficulties in young people.

2.  To examine whether The Guide is more effective than the usual school-based provision in increasing intended help-seeking of young people around mental health.

Primary hypotheses:

H~1~: Young people receiving YAM will report lower emotional difficulties between 3--6 and 9--12 months' follow-up than those who receive the usual school curriculum.

H~2~: Young people receiving The Guide will report increased intended help-seeking of mental health at 3--6 and 9--12 months' follow-up than those who receive the usual school curriculum.

### Implementation and process evaluation research questions {#s1-2-2}

1.  What is the state of participating schools' existing provision for supporting mental health and well-being, and their relationship with local mental health services, and does the nature of provision change over the course of the trial?

2.  To what extent does implementation follow the guidelines of the specified interventions, for example, in terms of fidelity and dosage?

3.  What is the relationship between implementation variability (eg, in terms of different levels of fidelity) and intervention outcomes?

4.  What are the experiences of schools (pupils and staff) and instructors/teachers in delivering/receiving YAM and The Guide?

5.  To what extent are interventions sustained after the mandated delivery period, and what do sustained interventions look like?

Methods and analysis {#s2}
====================

Design {#s2-1}
------

AWARE (Approaches for Well-being and Mental Health Literacy: Research in Education) is a three-arm, parallel group cluster randomised controlled trial: YAM or The Guide versus usual school provision (control). Interventions are delivered to whole school classes as part of the school curriculum. Assessment is undertaken at baseline (prior to intervention randomisation), and at 3--6 and 9--12 months after interventions have been delivered. See the [online supplementary material](#SP1){ref-type="supplementary-material"} for a detailed timeline of all measures and assessments.

10.1136/bmjopen-2019-029044.supp1

Site recruitment {#s2-2}
----------------

The study opened for school recruitment in March 2018 and will finish in July 2019. This study aims to recruit 144 secondary schools across England. Within each school, three Year 9 classes will be required to take part, resulting in participation of approximately 8600 young people.

Schools will be recruited via a variety of sources, including a paid-for school database (school mailings), the Schools in Mind network hosted by the Anna Freud National Centre for Children and Families (AFNCCF), AFNCCF collaborators, Public Health England, the National Institute for Health Research, local authorities and school commissioners. The project will also be advertised on social media platforms and in education publications and resources.

Participant recruitment {#s2-3}
-----------------------

Following school recruitment, participants are recruited via a two-stage process. First, schools select delivery groups who will receive an intervention (if allocated). Second, letters are sent out to parents/guardians of these delivery groups informing them of the study, as well as their right to opt out. The letter also explains that all children will only be involved in the project if they assent in class prior to completion of the baseline survey. Finally, assent is provided by young people reading through the information sheet and ticking boxes online agreeing to take part. If they do not assent, they cannot be part of the trial. The first young person joined the trial on 17 September 2018.

Inclusion/exclusion criteria {#s2-4}
----------------------------

Schools are eligible to participate if:

1.  They are willing to deliver/have an intervention delivered to around 60 Year 9 pupils in three delivery classes.

2.  They are able to allocate 1 hour per week to deliver the intervention for 6 weeks in the spring term of 2019 or 2020.

3.  They are able to send staff to one of the training sessions, if required.

4.  They sign a Memorandum of Understanding, data sharing agreement, and provide pupil lists to the research team.

Young people are eligible to take part if:

1.  Their parents/guardians provide consent.

2.  They provide written assent.

Interventions {#s2-5}
-------------

### Youth Aware of Mental Health {#s2-5-1}

YAM is a five-session structured programme to improve awareness via discussions on risk, protective factors and knowledge around mental health. Developed by researchers in Columbia University, New York, and the National Prevention of Suicide and Mental Ill-Health, Karolinska Institute Sweden, it aims to provide young people aged 14--16 years with a non-judgemental platform to explore topics such as depression, anxiety and suicidal thoughts. It also encourages young people to reflect on problem-solving in emotionally charged situations and dilemmas and incorporates methods used in suicide prevention programmes. It covers six main themes: (1) what is mental health?, (2) self-help advice, (3) stress and crisis, (4) depression and suicidal thoughts, (5) helping a friend in need, and (6) who can I ask for advice?

In the original intervention the 5-hour programme spans 3 weeks, but this has been adapted to 5 consecutive weeks in English schools to account for how the curriculum is structured. Sessions are delivered by instructors in a classroom setting with the support of a trained helper. Instructors completed a 5-day workshop delivered by YAM developers; instructors and helpers are professionals with a background in education, psychology, nursing, social work or youth work.

The sessions are supported by learning materials including posters (reflecting the six themes mentioned above) which are displayed in classrooms for the duration of YAM. Pupils are also provided with tailored booklets which address the same key themes and contain information on local support services that pupils can access. Pupils who think they may need support are encouraged to talk to YAM instructors, helpers or school staff and use the local and national support networks provided in the booklets and on the posters.

Role plays are a key component of YAM, allowing pupils the opportunity to explore and act out relevant issues from their everyday lives (eg, in relation to parents, peers, teachers, and so on) in a safe and confidential environment. The role play sessions comprise three themes: awareness about choices; depression and suicidal thoughts and feelings; and how to manage stress and crisis situations. However, the exact content can be adapted to the cultural needs of the group.

### Mental Health and High School Curriculum Guide {#s2-5-2}

The Guide was developed in Canada by Dr Kutcher in collaboration with the Canadian Mental Health Association in recognition of the increasing awareness of the importance of health literacy as a necessary foundation for improving health, extrapolated into the area of youth mental health. Originally a web-based curriculum, it aims to increase mental health literacy in both young people and school staff. The Guide is made up of six modules: (1) stigma of mental illness, (2) understanding the relationship between mental health and mental illness, (3) understanding specific mental illnesses, (4) adolescents' experiences of mental illness, (5) seeking help and finding support, and (6) the importance of positive mental health. It was originally developed to be delivered over 10--12 hours.

Adapted for a UK setting, The Guide is delivered over six consecutive 1-hour lessons by school staff. Modules remain the same; however, content has been modified to include more resources from England and less emphasis on PowerPoint presentations in favour of interactive discussions. The sessions in the first 4 weeks focus on a specific disorder or specific disorders and cover: bipolar disorder (week 1), panic disorder (week 2), schizophrenia and eating disorders (week 3), and depression, obsessive-compulsive disorder and attention deficit hyperactivity disorder (week 4). Week 5 covers support and where to get help, while week 6 focuses on stress. Homework exercises, such as a task on famous people with mental illness, are included as part of The Guide. All adaptations to The Guide for an English school setting have been approved by Dr Kutcher and were informed by a pilot study conducted prior to the parallel group cluster randomised controlled trial. School staff who deliver The Guide attend a 1-day face-to-face training delivered by an individual from the AFNCCF. The training aims to improve teachers' knowledge of mental health and mental illness and reduce stigma, as well as familiarise teachers with the adapted Guide materials so they are able to deliver the content.

### Usual Practice {#s2-5-3}

Schools allocated to the usual practice group are not required to deliver a specific mental health intervention during the programme (June 2018 to January 2021).

Outcome measures {#s2-6}
----------------

### Pupil measures {#s2-6-1}

All primary and secondary measures for pupils will be completed prior to the intervention and follow-up will take place at 3--6 and 9--12 months after the intervention has started. All questionnaires will be completed online.

Primary outcome measures:

-   For YAM: depressive symptoms (Short Mood and Feelings Questionnaire, SMFQ).[@R34]

-   For The Guide (intended help-seeking): General Help-Seeking Questionnaire (GHSQ).[@R35]

Secondary outcome measures:

-   Emotional difficulties: SMFQ for The Guide only.[@R34]

-   Intended help-seeking: GHSQ for YAM only.[@R35]

-   Positive well-being: Huebner Life Satisfaction Scale.[@R36]

-   Behavioural problems: Me & My Feelings Questionnaire---behavioural difficulties subscale.[@R37]

-   Support from school staff: Student Resilience Survey[@R38]---school connection subscale.[@R39]

-   Stigma (knowledge): Mental Health Knowledge Schedule---non-vignette items (items 1--6).[@R40]

-   Stigma (behaviour): Reported and Intended Behaviour Scale---intended behavioural subscale.[@R41]

-   Mental health first aid.[@R42]

-   Stigma (attitudes): Attitudes towards mental health.[@R29]

-   Paediatric Quality of Life (Child Health Utility-9D, CHU9D).[@R43]

### School staff {#s2-6-2}

Similar to pupils, school staff will complete measures around mental health literacy[@R20] prior to the intervention and follow-up will take place at 3--6 and 8--11 months after intervention has started. All questionnaires will be completed online.

### Measures for economic evaluation {#s2-6-3}

Information on service use will be completed online by pupils alongside the outcome measures. Data required to calculate cost will be collected online from both those who delivered an intervention and either a member of the school finance team (The Guide) or the AFNCCF (YAM) after intervention delivery.

-   Client Service Receipt of Inventory (CSRI; adapted for the study population).[@R47]

-   Service Information Schedule (SIS).[@R48]

Implementation and process monitoring measures {#s2-7}
----------------------------------------------

### Usual provision survey {#s2-7-1}

A member of the school's senior leadership team will be asked to complete two online surveys regarding current whole-school mental health provision. This will be prior to delivery of the intervention and approximately 9--12 months after the start of intervention delivery.

### Sustainability survey {#s2-7-2}

School staff who delivered an intervention will be asked to complete an online survey in relation to whether they, or others in the school, intend to continue delivering the intervention, and whether this has been adapted in any form. This will be administered approximately 8--11 months after the start of intervention delivery.

### Implementation surveys and outcome measures {#s2-7-3}

Intervention deliverers will complete one online implementation survey per delivery group after delivery has finished. Questions will cover six key aspects of implementation, namely fidelity, quality, dosage, participant responsiveness, reach and adaptations. Within this, three aspects relating to the social validity of the intervention (acceptability, feasibility and utility) will also be assessed using a standardised questionnaire.[@R49]

### Qualitative data and observations {#s2-7-4}

Qualitative implementation and process data will be collected towards the end of delivery of the interventions. Eight schools will be recruited from the main sample as qualitative case study schools in Year 1 of the project; one school per intervention at four of the hubs (excluding control). Case study schools will be recruited via expression of interest and sampled based on expression of interest and variation in their usual provision around mental health and well-being, drawing on data from two items in the usual provision survey:

1.  Please identify, in the last 2 years, the activities and approaches that have been used in your school and indicate who has delivered/provided these activities.

2.  How significant are the following potential barriers to providing effective mental health support within your school?

Face-to-face or telephone interviews will be conducted with two to three members of staff (including a senior leadership team member and a staff member delivering the intervention) and one to two focus groups will be conducted face to face with young people (approximately four to five young people in each focus group) at each school. Learning from the feasibility study indicated that this sample size would yield a large amount of rich qualitative data, while still being manageable in terms of the research team's capacity.

Interviews/focus groups will be semistructured, enabling the research team to guide the interviews/focus groups according to their topics of interest, but with the conversation around these topics being led by participants in terms of the issues that are most pertinent to them. The topics that the interviews/focus groups will cover include: staff experiences of delivering the interventions and receiving training; staff perceptions of barriers and facilitators to delivery; staff perceptions of impact; staff suggestions for improvement of the interventions; pupils' experiences of taking part in the interventions; pupils' perceptions of impact and helpful aspects of the interventions; and pupils' suggestions for improvement of the interventions. All interviews/focus groups will be audio recorded and transcribed verbatim.

The research team will also conduct an observation of a session of the intervention (excluding YAM) at each school to gather contextual information about what the interventions look like on the ground. No individual pupil or staff responses will be recorded, but field notes will be taken during the observation on the process of delivery, the layout of the room and the atmosphere during delivery.

Follow-up case study visits will be conducted in Year 2 of the project with a small number of schools from Year 1 who have sustained implementation of The Guide beyond the initial project delivery period, as identified through staff responses on the sustainability survey. In addition, as schools who express interest in taking part as a case study are likely to be the more engaged schools, there is also an opportunity in Year 2 of the project for a small number of telephone interviews to be conducted with staff at schools who have engaged less with the trial in Year 1. This could include schools who have dropped out of the trial, as well as those who have not sustained implementation of The Guide over time.

Randomisation of schools {#s2-8}
------------------------

To ensure approximate distribution across conditions randomisation will be carried out by Kings Clinical Trials Unit, minimising for regional representation, current mental health provision, deprivation (as indicated by free school meal eligibility) and urban/rural situation. Randomisation will take place after baseline data (staff and pupil questionnaires) have been collected. Schools (clusters) will be randomised in an equal allocation ratio (ie, 1:1:1). Only the statistician, quantitative data analyst and economist are blinded to intervention allocation. Data sets provided to these individuals will reference schools by a unique ID number (000--999).

Sample size calculation {#s2-9}
-----------------------

As described, two different outcomes will be used to evaluate the interventions in this study. The primary outcome for YAM will be depressive symptoms as measured by the SMFQ; and the primary outcome for The Guide, the GHSQ. For both interventions the primary endpoint is between 3 and 6 months after intervention. The choice of a short-term assessment as the primary endpoint seems more appropriate since we would expect effects to be observable in the short term. There is also a greater likelihood of attrition in the longer follow-up. Secondary analysis will be conducted examining long-term implementation fidelity and long-term effects.

The schools will be randomised to three groups (YAM, The Guide and Usual Provision). Due to the delivery of the intervention within classes, pupil-level data will be analysed allowing for school/class-level clustering. While cluster effects of emotional distress on *school* level are usually small[@R50] no data on *class*-level clustering were available. To our knowledge, no study has investigated school-level intraclass correlations (ICC) of help-seeking. Cluster effects for psychometric measures were evaluated in a joint feasibility study with the INSPIRE trial with n=1531 secondary students nested within 79 delivery groups at five schools at baseline. We found ICCs of 0.02 for both SMFQ and GHSQ (with upper borders of bootstrapped 95% CIs of 0.04 for the GHSQ and 0.05 for the SMFQ). Our sample size is based on an ICC of r=0.10, which is conservative given the estimates found in the literature and pilot.

The only school-level variables that will be used as predictors in the proposed analysis are the stratification variables which were assumed not to have any predictive power. Pretest values of the outcome measures will be used as predictors of within-school variance (conservative estimate of R^2^=0.20 was used). The study was planned for a minimally detectable effect size (MDES)=0.20 for the scores of the primary outcome of the respective trial arm. For the SMFQ this would translate into a group difference between 1.13 (our feasibility study) and 1.59 score points (Millennium Cohort Study at age 14[@R52]); for the GHSQ this would translate into a group difference of 0.25 (item average based on our feasibility study; no relevant external reference data identified).

Given these assumptions, an MDES=0.20 can be detected without controlling for any additional variables (significance level α=0.05; statistical power β=0.80) with a sample size of 90 schools (45 control, 45 intervention); and for an analysis taking pretest values into account an MDES=0.198 can be detected.

Since no evidence suggests that the two interventions show different effects, our sample size calculations for the YAM and The Guide trial arms are the same. The overall sample size is 135 schools (45 schools per arm; with 60 students each) of which the 45 control schools serve as comparators for both interventions. Incorporating the geographical spread, recruitment areas of the study and potential dropout both at student and school levels we plan to recruit at least 144 schools overall. To evaluate the potential impact of dropout, simulation studies were run and even under severe dropout (20% of schools and 10% of students in remaining schools) an MDES=0.22 was evaluated to be achievable, which was agreed by the research group, the funder and the advisory group as an acceptable margin.

Data management {#s2-10}
---------------

All quantitative data will be stored on the University of Manchester's secure server. The data manager (JS), along with the research assistants (EA and RM), will be responsible for cleaning and coding the data. Qualitative data will be stored at the Evidence Based Practice Unit. The qualitative data lead (ES), supported by the trials manager (DH), research officer (AM) and research assistants (RM and EA), will be responsible for storing and checking transcripts and ensuring their accuracy.

Analysis plan {#s2-11}
-------------

### Effectiveness analysis {#s2-11-1}

A detailed statistical analysis plan will be written and documented with the funder at least 3 months before the data are shared with the analyst (JRB). However, the analysis will mirror the power analysis in that a mixed model will be used to analyse the data, specifying random effects at the school (cluster) and class levels. The primary analysis will only use the intervention (dummy coded on class level) and stratification variables (on school level) as independent variables. Sensitivity analyses will be conducted for adding pretests and imputation of missing data. If subgroup analyses are to be conducted these will be defined in the statistical analysis plan as well.

### Economic evaluation {#s2-11-2}

#### Service use and costs {#s2-11-2-1}

An SIS will be designed to facilitate microcosting of the interventions. Information on services and supports used by the young people in the study will be collected using a specially adapted version of the CSRI.[@R47] From these data, we will investigate whether patterns of service use and associated costs differ between the intervention and control groups and explore whether any differences are driven by individual characteristics or baseline level of need.

#### Cost-effectiveness analysis {#s2-11-2-2}

Cost-effectiveness and cost-utility analyses will be undertaken for change in: (A) the primary outcome measure and (B) quality-adjusted life years (derived from CHU9D).[@R43] We will employ an analytical approach that allows for adjustment for confounders, the likely non-normal distribution of cost data, the joint analysis of cost and outcome measures, and subgroup analyses. Results will be presented as cost-effectiveness acceptability curves[@R53] plotting the probability that the intervention will be considered cost-effective compared with treatment as usual against different levels of willingness to pay for an improvement in outcome. Sensitivity analyses will be undertaken by varying assumptions used to calculate the intervention cost.

### Process and implementation analysis {#s2-11-3}

Descriptive statistics will be used to document usual school provision and how this changes over the course of the project, as well as to document the implementation of YAM and The Guide. Additionally, for documenting the implementation, we will compare 'implementation as delivered' from our survey data with 'intervention as planned'. Where applicable, the latter can be used to determine the proportion of participating schools who can be deemed to have achieved at least a minimum standard of intervention delivery (eg, 'on treatment' status). To assess the relationship between implementation variability and outcomes, multilevel modelling will be used, in which we fit the implementation data noted above (or on treatment status derived from said data) as explanatory variables at the school or class level, to assess the extent to which they are predictive of intervention outcomes at the pupil level.

Qualitative interview and focus group transcripts will be analysed using thematic analysis.[@R54] Up to three researchers will code or assign extracts of the transcripts to broad overarching categories, derived from the research questions (eg, perceptions of impact). The researchers will then break down the content (transcript extracts) coded within these overarching categories into themes and subthemes relevant to the categories. Finally, an additional member of the research team will recode 10% of the transcripts using the themes and subthemes for each category devised by the original researchers, suggesting additions or edits where necessary.

Patient and public involvement {#s3}
==============================

Views from school staff, pupils and experts by experience via Common Room Consulting were sought into the design and content for The Guide intervention. School staff and pupils also provided input into the finalised measures. The Anna Freud Young Champions, who are experts by experience, will be involved in dissemination of findings to school staff and young people via PDFs and reports. School staff and pupils did not provide input to the study design or recruitment and did not assess the study burden of the parallel group cluster randomised controlled trial.

Ethics and dissemination {#s4}
========================

Ethical approval and consent {#s4-1}
----------------------------

The study was approved by the University College London Research Ethics Committee (6735/009 and 6735/014). Consent/assent will be undertaken in a series of stages. Schools that have expressed an interest in the project, meet inclusion criteria and are selected for the programme will be asked to return a Memorandum of Understanding signed by a member of the senior leadership team. Further consent will then vary according to the different parts of the study. This study is congruent with General Data Protection Regulation legislation; the collection and processing of these data falls under Article 6(1)(e) (public task).

Pupil data {#s4-2}
----------

For outcome data, opt-out consent will be used for research purposes. Schools will send letters to parents/carers of participating pupils. Parents/carers can then contact the data manager if they do not want their child to take part in the evaluation. These pupils' data will be removed from the pupil lists provided by the school. For each remaining pupil, a unique password will be created to allow access to the online survey. Prior to completing online surveys, pupils will be presented with an information sheet and assent form which they must tick if they want to proceed with the survey. All information sheets outline confidentiality procedures for collecting, processing and storing data.

All other data (staff surveys, implementation surveys, qualitative data) {#s4-3}
------------------------------------------------------------------------

All other surveys, completed online, will require opt-in consent. As with pupils, individuals will be presented with an information sheet and consent form which they must tick prior to accessing the survey.

For qualitative interviews/focus groups, opt-in consent will be required. School staff and YAM instructors will be required to read and sign an information sheet and consent form. For pupils under the age of 16, letters will be sent home to parents/carers, which require a signed consent form to be returned if they are happy for their child to take part. Prior to interviews/focus groups commencing, the young people will also be asked to read an information sheet and sign an assent form. Consent/assent will not be sought for observations of intervention sessions as no individual staff or pupil responses will be recorded.

Monitoring of adverse events {#s4-4}
----------------------------

Adverse Events (AE), defined as a negative, emotional and behavioural occurrence, or sustained deterioration in a research participant, will be captured as part of the study. This includes Serious Adverse Events (SAE) which are a threat to life: suicidal ideation, suicidal intent, hospitalisation due to psychiatric use of substances and death including suicide. Other AEs, such as violent behaviour, self-harm, or any other event that an individual feels is important to report, will also be captured. School safeguarding leads will judge whether they believe the AE is likely related to the intervention.

The ongoing conduct and progress of this study is monitored by an independently chaired Advisory Group Ethics Sub-Committee (AGESC) and advisory group. On becoming aware of SAEs, the Principal Investigator (PI)/Trials Manager (TM) will report SAEs or AEs which are likely to be related to the intervention to the AGESC within 2 working days. Other AEs will be collated and reported quarterly to the AGESC. The University College London Research Ethics Committee will also be informed of AEs and SAEs using the same mechanisms. School and research safeguarding protocols will also be followed as standard in addition to the reporting and documenting of AEs.

Dissemination plan {#s4-5}
------------------

Results will be disseminated through a report to the Department for Education, as well as at conferences and in international peer-review journals.

Trial sponsor {#s4-6}
-------------

The trial is sponsored by the University College London.

Trial status {#s4-7}
------------

Recruitment for schools opened in March 2018 and will stay open until June 2019. The last participants will be followed up at a 1-year follow-up in January/February 2021.

Supplementary Material
======================

###### Reviewer comments

###### Author\'s manuscript

**Contributors:** NH, EA, RM and ES led on decisions for the process and implementation strand of the project and contributed to the writing of this section of the protocol. EB led on decisions for the economic strand of the project and contributed to the writing of this section of the protocol. JRB led on statistical and study design elements of the project, contributed to the writing of the sample size calculation and analysis plan, and contributed to the writing of these sections of the protocol. PP led on measures and their psychometric properties as well as mediation and moderation analysis. JS led on decisions relating to data management and contributed to the writing of this section of the protocol. DH, supported by AM, led on decisions relating to trial management, wrote the first draft of the protocol and contributed to edits and amendments in subsequent drafts. DH also led on ethical procedures and contributed to writing of this section of the protocol. JD is the principal investigator, conceptualised the overall trial design, has the final decision to sign off and contributed to the writing of this protocol. A measures group consisting of PP, JD, DH, AM, NH, EA, RM, JS, EB and JRB finalised measures for the trial. All authors read and approved the final manuscript.

**Funding:** This research was commissioned and funded by the Department for Education. The Department selected the interventions to be trialled and also chairs an advisory group the researchers report to regarding the progress and quality of the research. JD was (in part) supported by the National Institute for Health Research (NIHR) Collaboration for Leadership in Applied Health Research and Care (CLAHRC) North Thames at Bart's Health NHS Trust.

**Disclaimer:** The views expressed are those of the authors and not necessarily those of the Department for Education, the NHS, the NIHR or the Department of Health and Social Care. The Department for Education had no role in the design of this study and will not have any role in the analyses, interpretation of data or decision to submit results.

**Competing interests:** None declared.

**Patient consent for publication:** Not required.

**Ethics approval:** University College London Research Ethics Committee (6735/009 and 6735/014).

**Provenance and peer review:** Not commissioned; externally peer reviewed.
