In Australia and elsewhere, popular critics, moral entrepreneurs and psy-professionals continue to champion ever-evolving concerns about social media or digital technology provoking and spreading psychopathology in young people. What continues to garner attention is the presumed potential that social media participation—especially when pseudonymous, unsurveilled and ‘uncontained’—risks social contagion: the spontaneous spread of ideas or feelings through collective engagement online. Young people are positioned as highly suggestible to self-diagnosis and psychopathologisation via digital media content and participation. Yet, I argue, the concept and metaphor of contagion is unhelpful for understanding digital media and mental health; simple theories of contagion merely replicate psychiatric and psychological assumptions about sociality and ignore more complex and productive ways of understanding media and mental health. This chapter discusses contagion in psychology and psychiatric research and theory, and explores how contagion has been translated into digital contexts. I propose that media studies and social research may better support critical scholars to analyse youth mental health, psychopathologisation and digital media in more nuanced ways than psychiatric accounts of contagion. This could also contribute to more complex discussions about how therapeutic cultures are sustained through digital media.