Data collection
Outcomes were assessed at baseline, 9 months and 15 months using structured interviews (by research assistants not blinded to group membership) and self-reported measures (online Supplementary Table S3). Data were collected via a web-based, secure, data capture system (HealthTracker™). Interviews to complete the Health of the Nation Outcome Scale for Child and Adolescents (HoNOSCA) were held at the CAMHS, the participant's home, or an alternative location (according to the participant's preference). Participants were asked to complete other measures within 2 weeks of the HoNOSCA interview but were allowed a 3-month window.