Introduction: In spite of adolescents' rights to be involved in decisions that concern their health and life, limited research has been published reporting on their involvement in mental health research. Therefore, we aim to present experiences and reflections based on the involvement of adolescents in mental health research, to describe the collaborative relationship between researchers and coresearchers, including the values that underpin their collaboration.Methods: An autoethnographic approach was used, combined with group reflections. The process was jointly developed, carried out and analysed by adolescent coresearchers and the project's lead researcher over a period of 2 years. The article is jointly authored by the researcher and the ten coresearchers. Results: Six themes were developed to describe our collaborative relationship, resulting in the involvement of adolescents in decisions about research priorities; in planning and carrying out the research; through to analysis, dissemination and communication of results. The themes include: (1) Commitment motivated by altruism, personal interests and a common purpose; (2) Inclusiveness and support to reduce social uncertainty and strengthen collaboration; (3) Reduced power differentials while ensuring clarity of roles and tasks; (4) Diversity in representation to expand the perspectives of 'the adolescent voice'; (5) Self-determinationsupporting adolescents' involvement in decision-making processes; and (6) Flexible and systematic project management. The themes describe the collaboration, the underlying values and motives, the challenges faced and how they were overcome.

More than one out of ten adolescents suffer from mental illness at any given time. Still, there is limited knowledge about their involvement in mental healthcare. Adolescents have the right to be involved in decisions affecting their healthcare, but limited research focuses on their engagement and decision-making. Therefore, this systematic review aims to explore the existing experiences with, the effectiveness of, and safety issues associated with user involvement for adolescents’ mental healthcare at the individual and organizational level. A systematic literature review on user involvement in adolescents’ mental healthcare was carried out. A protocol pre-determined the eligibility criteria and search strategies, and established guidelines were used for data extraction, critical appraisal, and reporting of results. Quantitative studies were analysed individually due to heterogeneity of the studies, while qualitative studies were analysed using thematic synthesis. A total of 31 studies were included in the review. The experiences with user involvement were reported in 24 studies with three themes at the individual level: unilateral clinician control versus collaborative relationship, capacity and support for active involvement, the right to be involved; and two themes at the organizational level: involvement outcomes relevant to adolescents’ needs, conditions for optimal involvement. The effectiveness of user involvement was reported in seven studies documenting fragmented evidence related to different support structures to facilitate adolescents’ involvement. The safety associated with user involvement was not reported in any studies, yet a few examples related to potential risks associated with involvement of adolescents in decision-making and as consultants were mentioned.

Introduction Despite increased focus on development of mental health services worldwide, many adolescents still hesitate to reach out to the services when they need them. This might be linked to the lack of adolescent involvement in the development of services. This study aimed to explore adolescents' perspectives on the ideal healthcare services to meet their mental health needs. Methods A two‐stage qualitative study was carried out to explore the perspectives of adolescents on the healthcare services to support their mental health. In the first stage, data from 295 adolescents attending a mental health seminar were analysed using qualitative content analysis. In the second stage, in‐depth perspectives of 10 adolescent coresearchers were gathered through self‐reflection and group discussions to further explore the categories developed in the first stage. Thematic analysis was used to develop the themes answering the research question. Ten adolescent coresearchers planned the study, collected and analysed data and authored the manuscript, with the support of a senior researcher. Results Five themes describe adolescents' perspectives on the ideal healthcare services to meet their mental health needs: (1) Culturally Sensitive and Responsive; (2) Communication of Information; (3) Easy Access; (4) Variety of Support; and (5) Consistency. Culturally Sensitive and Responsive services influenced all other themes. The themes describe suggestions for mental health service improvement, including how to manage the barriers that adolescents face to receive help from the mental health services. Discussion This study highlights the importance of culturally sensitive and responsive services. It raises the need for an expanded definition of culture going beyond nationality and ethnic background. Adolescents need flexible services that meet their individual mental health needs. This has implications for practitioners, educators, system organizers and researchers, who should also involve adolescents in planning, implementing and assessing the services. There is a need for a self‐learning system to continuously adapt to user feedback. Conclusion This study provides insight into adolescents' perspectives on the ideal mental health services. It offers suggestions for ways to improve services to better meet the individual mental health needs of adolescents. Additional research is needed to further develop and implement service changes, as well as to assess their acceptability, effectiveness, cost‐effectiveness and safety. Patient or Public Contribution This is a study lead by adolescents. Adolescent coresearchers have, with the support of a senior researcher, planned and carried out the study, collected and analysed data and authored the manuscript.

IntroductionUser involvement has become a growing importance in healthcare. The United Nations state that adolescents have a right to be heard, and user involvement in healthcare is a legal right in many countries. Some research provides an insight into the field of user involvement in somatic and mental healthcare for adults, but little is known about user involvement in adolescents’ mental healthcare, and no overview of the existing research evidence exists.Methods and analysisThe aim of this systematic review is to provide an overview of existing research reporting on experiences with and the effectiveness and safety issues associated with user involvement for adolescents’ mental healthcare at the individual and organisational level. A systematic literature search and assessment of published research in the field of user involvement in adolescents’ mental healthcare will be carried out. Established guidelines will be used for data extraction (Cochrane Collaboration guidelines, Strengthening the Reporting of Observational studies in Epidemiology and Critical Appraisal Skills Programme (CASP)), critical appraisal (Cochrane Collaboration guidelines and Pragmatic-Explanatory Continuum Indicator Summary) and reporting of results (Preferred Reporting Items for Systematic reviews and Meta-Analyses, Consolidated Standards of Reporting Trials and CASP). Confidence in the research evidence will be assessed using the Grading of Recommendations Assessment, Development and Evaluation approach. Adolescents are included as coresearchers for the planning and carrying out of this systematic review. This systematic review will provide an overview of the existing research literature and thereby fill a knowledge gap. It may provide various stakeholders, including decision-makers, professionals, individuals and their families, with an overview of existing knowledge in an underexplored field of research.Ethics and disseminationEthics approval is not required for this systematic review as we are not collecting primary data. The results will be published in a peer-reviewed journal and at conference presentations and will be shared with stakeholder groups.