Helping adolescents to better support their peers with a mental health problem: A cluster-randomised crossover trial of teen Mental Health First Aid:

Background:teen Mental Health First Aid (tMHFA) is a classroom-based training programme for students aged 15–18 years to improve supportive behaviours towards peers, increase mental health literacy and reduce stigma. This research evaluated tMHFA by comparing it to a matched emergency Physical First Aid (PFA) training programme.Methods:A cluster-randomised crossover trial matched four public schools in two pairs and then randomised each to first receive tMHFA or PFA for all Year 10 students. In the subsequent calendar year, the new Year 10 cohort received the opposite intervention, giving eight cohorts. Online surveys were administered at baseline and 1 week post-training, measuring quality of first aid intentions, mental health literacy, problem recognition and stigmatising beliefs, towards fictional adolescents with depression and suicidality (John) and social anxiety (Jeanie).Results:A total of 1942 students were randomised (979 received tMHFA, 948 received PFA), 1605 (84%) analysed for the John vignet...