Medical students, especially those in postgraduate training, face a complex array of challenges such as fatigue; work-life balance conflicts; difficulties managing dual hierarchies (hospital and university). Surprisingly, residents receive little to no dedicated training in recognizing and managing psychiatric disorders, except for psychiatry residents. This gap is exacerbated by persistent stigma towards psychiatric conditions. The Mental Health First Aid (MHFA) training approach could offer an innovative solution, addressing the root of the problem. This prospective, single-center cohort study aims to compare (1) the mental well-being of first-year specialty residents in the Lyon subdivision exposed to MHFA-trained peers; with (2) the mental well-being of unexposed second-year specialty residents. The hypothesis is that exposure to peers trained in MHFA improves well-being and reduces symptoms of burnout, depression, and anxiety at 3, 6, 9, and 12 months among peer residents.

Inclusion Criteria:

• subject to the non-opposition of the residents, all medical residents entering their first and second year of specialized studies (DES) on November 1, 2025, in the city of Lyon will be included in the study.

Exclusion Criteria:

• refusal to participate AND in the unlikely cases where:
• subject under guardianship or curatorship;
• subject unable to give free and informed consent;
• subject under legal protection