Apprehension in shoulder instability is a syndrome more than a symptom. It involves local mechanical factors at the level of the glenohumeral joint, peripheral neurologic factors, and central neurologic factors. These consist in complex alterations in cerebral networks that seem to persist despite surgical stabilization. Persisting apprehension may compromise surgical results and hinder patients performance in sports or even daily life activities. Understanding the multisystemic origin of apprehension is thus important to improve patient care. This Privat Docent thesis is the continuation of the author's Medical Doctor thesis. It includes a line of research projects carried out over the last decade about apprehension. The aim is to regroup and summarize its different causal factors, and to offer a perspective for future development in terms of research and treatment, involving multimodal approaches that range from surgical techniques to cognitive behaviour therapy, and augmented reality.