Purpose Although youth participation is oft-acknowledged as underpinning mental health policy and service reform, little robust evidence exists about the participation of children and youth in mental health policymaking.Method A scoping review based on Arksey and O'Malley's framework was conducted to identify and synthesize available information on children and youth's participation in mental health policymaking. Published studies up to November 30, 2020 were searched in Medline (OVID), PsycINFO (OVID), Scopus, and Applied Social Sciences Index and Abstracts (PROQUEST). Unpublished studies were identified through Google Scholar and targeted web searches October to December, 2020. Three reviewers performed screening and data extraction relevant to the review objective, followed by an online consultation. ResultsFrom 2,981 records, 25 publications were included. A lack of diversity among the youth involved was found. Youth were often involved in situational analysis and policy design, but seldom in policy implementation and evaluation. Both the facilitators of and barriers to participation were multifaceted and interconnected. Despite a range of expected outcomes of participation for youth, adults, organizations, and communities, perceived and actual effects were neither substantially explored nor reported.

Indeed, policymaking is one of the most challenging areas in which children's participation rights are implemented (Perry-Hazan, 2016).The global movement for youth mental health is gaining momentum. Worldwide, one in seven adolescents is estimated to experience mental health problems (UNI-CEF, 2019). About 50% of these problems start by the age of 14 and 75% start by the age of 24 (Fusar-Poli, 2019). Depressive disorders are the third cause of adolescent disability-adjusted life years (DALYs) lost globally, while anxiety disorders are the fifth cause of DALYs lost among adolescent girls (World Health Organization, 2017). The COVID-19 pandemic and ongoing social, economic, and BackgroundYoung people's participation in making decisions that affect their life has been recognized as a human right since the adoption of the United Nations Convention on the Rights of the Child (UNCRC) in 1989 (UNGA, 1989). Despite the advancement of child and youth participation in the past 30 years, challenges persist, ranging from concerns about tokenism and the lack of impact on decision-making to the lack of sustainability of participation (McMellon & Tisdall, 2020). A lack of diversity when children and young people participate is an ongoing familiar challenge in the Extended author information available on the last page of the article