Background and Aims: Digital media have become a fundamental aspect of daily life for children and adolescents, influencing cognitive, emotional, and social development. The present work explores the dual nature of digital media use, identifying both positive and negative impacts on well-being and development. Methods: A comprehensive review of existing literature was conducted to explore the interplay between digital media use and its effects on child and adolescent well-being. The study employs the Digital Mediause Effects (d-MUsE) model to analyze psychological mechanisms and contextual factors mediating these effects. Results: Functional media use promotes positive mental, physical, and social outcomes, while dysfunctional use is linked to negative psychological consequences, such as increased anxiety, depression, and social isolation. The proposed d-MUsE model highlights the interplay of psychological mechanisms and contextual factors-both proximal and distal-that mediate the effects of digital media on short- and long-term well-being. Discussion: The present work endeavours to refine our existing comprehension of the intricate interplay of elements and mechanisms underpinning functional and dysfunctional employment of digital media. Prospective research trajectories, which spotlight factors that hitherto remained at the periphery of investigative scrutiny, find discourse in this synthesis.  Kulcsszavak: digital media, adolescents, development, well-being, mental health, smartphone use, social media use