This study will look at whether a teaching method called "Sequential Case Triangle-Based Project-Based Learning" helps nursing students learn psychosocial care skills better. The study will take place during a Psychosocial Nursing course for fourth-year nursing students. Students will be divided into groups. Each group will work on one part of a patient case (creating the case, assessing it, or planning nursing care) using short role-play videos, building on the work of the group before them. Before and after the course, students will complete surveys measuring their psychosocial care competency, teamwork (cooperative learning) skills, and clinical reasoning skills. The study will compare students' scores before and after the course to see if this teaching method improved these skills.