The study was a cluster randomized trial with schools as clusters and individual teachers the participants. A cluster design was used because it was not feasible to randomly assign individual teachers who were working in the same school because: (1) there may have been contamination of information provided across groups within the same school, and (2) schools may have responded to the training with changes in policy or procedures which would affect all teachers. Schools were randomly assigned to either receive training immediately or be placed on a wait list to receive training once the trial had finished. The trial has been registered with the Australian and New Zealand Clinical Trials Registry (ACTRN12608000561381).
Eligible participants were teachers of the middle years in school (i.e. Years 8-10, ages 12-15 years) at schools willing to participate in the study. Students taught by these teachers were also surveyed.
Eligible clusters were all schools in the government, Catholic or independent systems in South Australia with Year 8-10 classes. These schools were sent a letter from the South Australian Department of Education and Children's Services explaining the study and inviting participation. Schools had to be willing to be randomized to do the training either in Terms 1 or 2 of 2008 (intervention schools) or Terms 3 or 4 of 2008 (wait-list control schools).
Teachers received a modified version of the Youth Mental Health First Aid course. To meet the scheduling needs of schools, the course was organized into two one-day parts of seven hours each. Part 1 was designed for all education staff and covered departmental policy on mental health issues, common mental disorders in adolescents (depressive and anxiety disorders, suicidal thoughts and behaviours, and non-suicidal self-injury) and how to apply the mental health action plan to help a student with such a problem. Part 2 was for teachers who had a particular responsibility for student welfare. It provided information about first aid approaches for crises that require a more comprehensive response and information about responses for less common mental health problems. Topics included how to give initial help to students who are experiencing a psychotic or eating disorder or substance misuse. Training was administered at the participants' school, with all available staff participating.
As documentation of the intervention, there was a lesson plan for each session, the existing Youth Mental Health First Aid manual  and a set of mental health factsheets. Lesson plans were developed by two Mental Health First Aid trainers of instructors who had previously worked as teachers. Additional material was added by staff of the Department of Education and Children's Services. Each course was conducted by two instructors, one from the Department of Education and Children's Services and the other from the Child and Adolescent Mental Health Service. These instructors received a one-week training program in how to conduct this modified Youth Mental Health First Aid course. They were trained by two experienced trainers, including Betty Kitchener who devised the Mental Health First Aid course.
For teachers, the hypotheses tested were that mental health first aid training improves the following: mental health knowledge, stigmatizing attitudes, confidence in helping students, helping behaviours towards their students, knowledge of school policies and procedures for dealing with student mental health problems, support given to colleagues with mental health problems, seeking information about mental health problems and their own mental health. The primary outcome measure for the trial was teacher knowledge.
For students, the hypotheses tested were that the mental health first aid training of their teachers would lead to an increase in the information they receive about mental health problems from their teachers, and that their mental health would improve.
All hypotheses pertained to the individual rather than the cluster level.
The following teacher outcomes were measured at the individual level:
Knowledge about mental health problems
Teachers were administered 21 questions assessing information taught in both day 1 and day 2 of the course. Questions consisted of statements rated as "Agree", "Disagree" or "Unsure". The score was the number of questions answered correctly. Examples of items are: "Most adolescents with mental health problems get some sort of professional help", "It is not a good idea to ask someone if they are feeling suicidal in case you put the idea in their head" and "Depression can increase a young person's risk taking behaviour, e.g. reckless driving, risky sexual involvements".
Recognition of depression in a vignette
Teachers were given a vignette describing a 15-year old ('Jenny') with major depressive episode  and asked an open-ended question about what they thought was wrong with the person. Responses which mentioned "depression" were scored as correct.
Stigma towards depressed students
Teachers answered personal and perceived stigma items in relation to 'Jenny' . Examples of personal stigma items are: "A problem like 'Jenny's' is a sign of personal weakness", "People with a problem like 'Jenny's' are dangerous", and "If I had a problem like 'Jenny's', I would not tell anyone". Perceived stigma items were the same except that they asked about what "most other people believe". These items were intended to be analyzed as scales based on a previous principal components analysis . However, because the principal components could not be replicated in the teacher data, the responses to these questions were analyzed as individual items.
Beliefs about treatment of depression which are like those of health professionals
Teachers were given a list of 36 categories of people, medicines or other interventions and asked whether each of them is likely to be helpful, harmful or neither for 'Jenny'. Eleven of these interventions have been previously assessed by a consensus of clinicians as likely to be helpful . The score was the number of these 11 interventions that teachers rated as likely to be helpful.
Confidence in providing help
Teachers were asked "How confident do you feel in helping a student with a mental health problem?" (Not at all, A little bit, Moderately, Quite a bit, Extremely). A parallel question was asked about confidence in providing help to a work colleague with a mental health problem.
Intentions to provide help to a depressed student
Teachers were asked "If you had regular contact with a student like 'Jenny', how likely are you to immediately: contact the family; discuss your concerns with another teacher; discuss your concerns with the counsellors; discuss your concerns with a member of the admin team; have a conversation with the student; talk to peers of the student; do nothing". Each item was rated on a 5-point scale from Never to Always.
Help provided to students
Teachers were asked in relation to the past month "Did you talk with a student about their mental health problem? (Never, Once, Occasionally, Frequently)". If yes, did you do any of the following: spent time listening to their problem, helped to calm them down, talked to them about suicidal thoughts, recommended they seek professional help, anything else".
First aid provided to colleagues
Parallel questions to those above were asked about first aid provided to colleagues, using the stem question "Did you talk with a school staff member about their mental health problem?"
School practices and policies
Teachers were asked in relation to the student in the vignette: "To what extent do you agree with the following as an important long-term strategy to support this student's learning and well-being: Review curriculum options/classroom practices; Review/change school policy; Set up planned family liaison; Set up planned community liaison; External support for student and family; Improve relationships within the school (i.e. teacher-student, student-student)" (Never, Rarely, Sometimes, Often, Always). Teachers were also asked the following questions in relation to the past month: "Did you discuss mental health problems of students with other teachers? Were mental health issues raised in staff meetings? Did you talk about your own mental health to a school staff member? Did you visit any websites giving information about mental health problems? Did you read any books or other written materials about mental health problems? (Never, Once, Occasionally, Frequently). Does your school have a written policy about how to deal with student mental health problems (Yes, No, Unsure)? Over the past month, how often did you put this policy into practice? (Never, Once, Occasionally, Frequently)."
Teacher psychological distress
Teachers completed the K6 Psychological Distress Scale .
The following student outcomes were measured at the individual level:
Recognition of depression in a vignette
Students were presented with the 'Jenny' vignette and asked the same recognition question that was used with teachers.
Stigma towards a depressed peer
Students were asked questions about personal and perceived stigma in relation to 'Jenny' .
Beliefs in the helpfulness of school staff for a depressed student
Student were given a list of 28 people or services, including a teacher and a school/student counsellor, and asked to rate them as likely to be helpful, harmful or neither for 'Jenny'.
Help received from school staff members
Students were asked "Over the past month, have you talked with a school staff member about any mental health problem you may have? (Never, Once, Occasionally, Frequently). If yes, did this person do any of the following: spent time listening to your problem, helped to calm you down, talked to you about suicidal thoughts, recommended you seek professional help, anything else".
Information received from teachers
Students were asked "Over the past month, have you received any information about mental health problems from your teachers? (Yes, No). If yes, how was this information presented: class lesson from teacher; poster, pamphlet, brochure or book; referral to website; talk from person other than the teacher; other".
Student mental health
Students completed the Strengths and Difficulties Questionnaire . This is a 25 item questionnaire asking about how things have been for the young person over the last six months. The questionnaire yields subscale scores (5 items each) for emotional problems, conduct problems, hyperactivity/inattention, peer relationship problems and prosocial behaviour.
All outcomes were measured by printed questionnaires distributed by the school staff. Questionnaires to staff were administered at baseline (pre-test), immediately after training (post-test) and 6 months after (follow-up). Questionnaires were only provided to students whose parents gave consent. These questionnaires were administered at pre-test and follow-up only.
Sample size estimation
Required sample size was estimated using software for power analysis in cluster randomized trials . Likely effect sizes were taken from a randomized trial of Mental Health First Aid in a workplace setting . In this workplace trial, recognition of the disorder in a vignette improved 10% in the intervention group compared to 1% in the wait-list control group. Similarly, advising someone to seek professional help increased by 10% vs 1%. To detect this effect in an unclustered trial with 80% power at the 0.05 significance level, required n = 200. The average school was estimated to have 30 teachers, giving a cluster size of 30. The intra-class correlation (ICC) was unknown. Examining ICC values from .01 to .10, the number of required clusters varied from 10 to 28. A previous cluster randomized trial of MHFA in a rural area  found ICCs ranging from 0.002 to 0.15, with most < 0.05. We therefore assumed an ICC of 0.05, which required a minimum of 18 schools to be randomized. We managed to recruit 16 schools for the trial, 14 of which participated as randomized.
Randomization: sequence generation
The 16 schools were paired to be alike in socioeconomic characteristics. The pairing was carried out on the basis of: a scale of education disadvantage, size, location (metropolitan vs rural/remote), and gender (single vs mixed gender schools). Using the Random Integers option of Random.org, one school in each pair was randomly assigned to the immediate group and the other school to the wait-list group, by generating a 1 or a 2 for each pair (1 = immediate, 2 = wait-list).
Randomization: allocation concealment
Allocation was based on clusters rather than individuals, so that all teachers at a school received the same intervention. Schools were told about the allocation before their teachers completed the pre-test questionnaire. This was necessary so that they could schedule the staff training days.
AFJ randomly assigned the schools. Participating schools were enrolled by a staff member of the Department of Education and Children's Services (HS) who informed them of their allocation after agreement to participate had been received.
Blinding of participants was not possible. Post-test and follow-up questionnaires were self-completed by teachers who knew whether they had completed the training or not. Students were not informed about whether teachers at the school had received training, but no systematic attempt was made to blind them.
The analysis of these multilevel or nested data required that the correlation of responses by individual participants between the measurement occasions and the correlation between participant responses within schools be taken into account. For that reason, mixed-effects models for continuous and dichotomous outcome variables, with group by measurement occasion interactions, were used to analyse the data. These maximum-likelihood based methods produce unbiased estimates when a proportion of the participants drop-out before the completion of the study, provided that they are missing at random [19, 20].
In the current study, all the participants included in the analyses completed the first questionnaire. Twenty-two percent of teachers did not complete the post-test questionnaire and 28% the follow-up questionnaire. In relation to the students, 24% did not complete the follow-up questionnaire.
All analyses were performed using Stata Release 10 .
Ethical approval was given by the Youth and Women's Health Service Research Ethics Committee at the Women's and Children's Hospital.