This paper proposes an advanced method for monitoring human behavior by integrating brain–computer interface technologies into intelligent decision support systems. Developed within a European research framework, the study combines multiple physiological sensing modalities, real-time biomedical signal processing, and artificial intelligence techniques to assess key cognitive states such as psychological stress, mental workload, and intentional deception. Two specialized platforms were designed and implemented: one for indoor use and controlled environments, and another for outdoor use and dynamic operational contexts. Both platforms were tested and validated in laboratory conditions as well as in realistic field scenarios involving cognitive and emotional challenges. The experimental results indicate that brain–computer interface-based systems can significantly improve situational awareness, enhance decision-making processes, and support psychological profiling, especially in high-stakes or safety-critical environments. This research highlights the growing importance of cognitive monitoring tools in applications such as healthcare, security, military operations, and advanced human–machine collaboration. Furthermore, the integration of neural and physiological data into decision systems opens new perspectives for adaptive and personalized technologies capable of responding to users’ mental states in real time. The findings confirm the viability and potential of brain–computer interfaces as core components of future intelligent monitoring and support systems.