Falls among older adults are considered a public health issue due to their frequency, their consequences, and the effectiveness of certain prevention programs. However, falls are very often not reported by individuals or by healthcare professionals. The author posits that a fall is a traumatic event; the author examines, on the one hand, its impact on the life trajectories of people aged 50 and older and, on the other hand, adaptation to this event. Drawing on various types of existing data, this study highlights the numerous impacts of falls beyond health, particularly on social dimensions and quality of life; compared to other health events, a fall affects several indicators, with effects manifesting in both the short and long term. The author identifies factors contributing to vulnerability to falls: the timing of the event is a key determinant, as adaptation is more difficult when the fall occurs in individuals under 65; the severity of the event also hinders the likelihood of adapting to it. However, institutional resources are underutilized by those affected, and the effects of a general fall prevention program based on physical activity and health education are modest and do not persist beyond the intervention. Ultimately, this thesis makes an original contribution to the psychosocial study of falls as viewed through the vulnerability model: its conclusions allow for the adjustment of interventions that should prioritize strengthening individual resources and strategies and then address the identity-related and emotional consequences of the fall. [author’s abstract]