Ethical reasoning is an important skill for all physicians who often face complex ethical dilemmas in their daily practice. Therefore, medical training should include methods for learning ethical theories and concepts, as well as how to apply them in practical situations. Assess the contribution of an Ethical Reasoning Learning session to fifth medical students' training through a comparison of results of the same objective and structured clinical examination (OSCE) in the form of simulated interview before and after sessions. Four 45- minutes' sessions of Ethical Reasoning Learning (ERL) were implemented during a psychiatry internship for four groups of 5th-year students of the faculty of medicine of Monastir (Tunisia). Each session was divided into 7 parts: introduction, reading of a clinical vignette, brainstorming concerning the problems posed by this clinical situation, classification of the problems, identification of the principles of medical ethics, construction of the ethical matrix, and a conclusion. Fifty-seven students participated in the study divided into 4 groups. We found a significant difference in the means of the OSCE scores before and after the ERL session and a significant difference between the probability of respecting medical secrecy during pre and post-ethical reasoning learning sessions (p <0.001). We have found an effect of ERL sessions on the acquisition of this ethical competence by medical students. We learned that an ERL session has improved medical training in ethics applied to psychiatry. Other sessions dealing with other ethical skills are necessary to confirm these results.