Seventy-five percent of mental disorders emerge before age 25. At any given time, 1 in every 8 people under the age of 18 years, living in a high-income country, has a mental disorder requiring specialised health services. Globally, mental disorders are a leading cause of disability among children and youth, with the burden increasing into young adulthood. This burden is compounded by multimorbidity (> 1 mental disorder and/or a concurrent medical diagnosis) and complexity (profound, interacting needs in other areas such as gender and structural racism, relationships, sleep, education), which are common complications. By and large, the child and youth mental health (CYMH) field lacks a suite of effective interventions personalized to individual need and informed by robust clinical trial evidence. A research network for CYMH RCTs does not yet exist in Canada unlike other high-income countries such as the UK and Australia, but would provide critical infrastructure for Canadian trialists to develop high-quality studies that reflect real-world complexities, recruit diverse and representative CYMH populations, and conduct multi-centre trials across the country Reflecting on this lack of infrastructure, as of January 2024, in, there are 25 active CYMH trials in Canada: 5 are drug trials with 3 led by Canadian PIs at single centres, and 20 are psychosocial trials with 6 being conducted across multiple sites, and of these, just 2 are being conducted in more than one province by a Canadian PI. The only way that CYMH outcomes will improve for Canada’s children and youth is to develop a national network and evidence base of interventions that work in Canadian contexts.

Our goal is to establish a pan-Canadian RCT network that is regarded as the network for conducting CYMH trials in Canada. We will develop sustainable infrastructure that optimises and supports the development, conduct, and reporting of CYMH RCTs across the country through: 1) high-quality input into trial design and planning, including feasibility, engagement (youth, family, Indigenous partners), and IDEA (inclusion, diversity, equity, accessibility); 2) efficient mobilisation of shared resources and standardised approaches; 3) collaboration with specialist networks and knowledge translation activities with decision/policy-makers; and 4) mentorship and training to build and sustain trials capacity.

The network will align with international recommendations, emerging CYMH frameworks, and trial standards to place Canadian trialists at the international forefront of robust testing of original ideas and attract investment. In accordance, the network will support: (1) Personalised and precision trials (e.g., staging and stepped care models) with adaptive designs (e.g., multi-arm, multi-stage RCTs) to address heterogeneity of treatment effect and complexity. (2) RCTs of transdiagnostic interventions (e.g., basket trials) that expand treatment generalisability by targeting symptoms that span disorders and syndromes rather than narrow diagnoses, or stratifying treatment by multimorbidity or complexity. (3) Trials with concurrent treatment and implementation evaluation (e.g., stepped wedge or hybrid RCTs) and harmonised (core) outcome measures to explore effects within and across patients and settings.