This article presents the steps and results of the empirical testing of a theoretical longitudinal model, derived from Roy's nursing conceptual model, of the psychosocial determinants of adaptation in different target groups. The model was elaborated and empirically verified based on the integrated results of four longitudinal studies involving groups vulnerable to mental health problems. By means of structural equation analyses, the cross-sectional model was verified at two points in time. The results showed that the model was relatively stable over time. The model was also tested using longitudinal data. Results showed little consistency in the patterns of relationships across studies. The significant links that emerged from the analyses shed some light on the complexity of the process of adaptation to different types of stressors. They underscore the importance for nursing practice to develop interventions aimed at certain variables: perceived stress, conflicts in the exchange of support, and passive and avoidance coping strategies. The results also highlight the importance of the relationship between perceived stress, passive/avoidance coping strategies and psychological distress.