Competing interests: The BMJ has judged that there are no disqualifying financial ties to commercial companies. The authors declare the following other interests: TF is part of the Research Advisory Group for Place2Be, a charity providing mental health support in schools and vice-chair of the Association of Child and Adolescent Mental Health. DG is a member of the National Suicide Prevention Strategy Advisory Group (England) and Samaritans policy, partnerships, and research committee. The BMJ policy on financial interests is here: https://www.bmj.com/sites/default/files/attachments/resources/2016/03/16-current-bmj-education-coi-form.pdf.