Editorial: Child and adolescent mental health research in a digital age: missed opportunities and overlooked threats

Digital technologies are central to child and adolescent mental health research and intervention delivery. Online platforms expand access, reduce logistical barriers and create new opportunities for young people to engage directly with research and care. At the same time, digital methods introduce threats to research integrity and validity, particularly in randomised controlled trials and large observational studies relying on self‐selected samples. In this editorial, we argue that digital child and adolescent mental health research has missed opportunities and overlooked threats across three interconnected domains: young people's agency to participate in research and provide self‐reported data, representation of the populations targeted by digital interventions and inclusion of marginalised or underserved groups. We highlight how unusual patterns of participation – ranging from symptom misinterpretation to deliberate fraudulent enrolment – intersect with these domains and challenge a study's internal and external validity. Addressing these issues is essential for digitally enabled mental health research to translate into trustworthy and generalisable evidence.