Abstract
Imposter participants are dishonest participants who fake their identities or exaggerate their experiences to participate in research. This appears to be a rising problem in quantitative and qualitative research as well as lived experience groups for child and adolescent mental health research. Imposters in research present great challenges for young people's safety, privacy, and well-being, and the data integrity of affected research studies. Although strategies have been suggested to identify and address this challenge, they come with limitations. Also, there are no evidence-based guidelines or frameworks about imposter data. We discuss key issues and considerations and propose actionable steps for researchers and practitioners working with young people. We also make a call for action for robust research to improve how we prevent, identify, and address imposters in child and adolescent mental health research.