Objectives: There has been little evaluation, by means other than cognitive variables, of medical school curricula that include problem-based learning (PBL). This study aimed to investigate whether medical students' affect tolerance, an important prerequisite of empathy, was influenced by individual courses.

Design: The study is pseudo-randomised and cross-sectional, using a test of affect tolerance in students in their first, sixth and eighth term of medical school, during which they were kept together as one group for their pre-clinical studies, but were subsequently separated during the clinical part and were sent to two different university hospitals that used different teaching methods.

Subjects: Medical students.

Setting: University of Lund Medical School, Sweden.

Results: After receiving a short course in communications skills training, students in the sixth term had significantly higher mean scores on the test than students in their first term. In the eighth term, which is the surgery term, the mean scores for students attending the PBL course were still as high as those for students in the sixth term, while students in the course using conventional pedagogical methods had significantly lower mean scores.

Discussion: Since the content of the courses was similar and the composition of the two groups also fairly similar, we attribute the difference to the differing teaching methods. In the PBL course, the students were given continued and integrated communication skills instruction, in which it was possible for them to learn strategies to counteract the development of rigid psychic defences, which constitute an obstacle to affect tolerance and empathy.