For decades, research on technology use and mental health has been based on the assumption that identifiable structures of ‘design’ are psychologically relevant for their users. This has been central especially for the nosological emergence of ‘behavioural addictions’, which currently include two formal diagnoses on technology use: problems related to playing gambling games (gambling disorder) and videogames (gaming disorder). Alas, the research on identifying ‘addictive’ design structures has suffered from major construct validity issues. To make progress over those issues, I draw from the history of ‘vitality affects’ in psychiatry and introduce vitality structures as a design-phenomenological framework that can help researchers conceptualise psychologically relevant ‘bonds’ between entities of game design and corresponding player phenomenology. Vitality structures are not natural kinds to be discovered but pragmatic constructs to be used—and useful as long as they communicate what is both identifiable and empirically prevalent. As a demonstration of practice, I propose working conceptualisations of three vitality structures, which surface in videogames played by gaming treatment-seekers. Systematic research programs for identifying relevant vitality structures can lead to construct-valid and replicable design effects.