Addressing Psychological Distress in College Students Through Mindfulness Training: A Pre–Post Intervention Across Three Cohorts with Different Delivery Methods

College students are particularly vulnerable to psychological distress, including anxiety, depression, and chronic stress, often triggered by academic pressure, developmental challenges, and events such as the COVID-19 pandemic. This study examined the effectiveness and feasibility of a structured mindfulness-based program—Mindfulness Laboratory (MLAB)—delivered over three academic years to psychology students in Italy through online, hybrid, and in-person formats. A total of 194 students participated, with 176 completing pre- and post-intervention assessments. Standardized self-report measures evaluated mindfulness (FFMQ, MAAS), perceived stress (PSS), resilience (RS-14), sleep quality (PSQI), depressive symptoms (BDI-II), anxiety (STAI-Y1, STAI-Y2), and self-compassion (SCS). A non-randomized control group of 51 students who did not undergo the intervention was also included. The results showed significant improvements in mindfulness, perceived stress, anxiety, and depression, with a smaller but significant increase in resilience. Sleep quality remained stable, while self-compassion levels slightly declined. Surprisingly, no significant differences were found across the three delivery formats, suggesting comparable effectiveness regardless of modality. These results support the feasibility and benefits of mindfulness-based interventions for university students. Further controlled studies with long-term follow-up are needed to confirm upon these findings.