This paper presents the results of a study on the impact of a new integrated medical educational design on students' approaches to learning. Although the new program was based on curriculum features identified in the research literature as likely to promote deeper approaches to learning, the results revealed a more complex response from students. While a proportion of students reacted as expected and changed to deeper approaches, a significant subgroup moved in the opposite direction and adopted more surface approaches. Further analysis revealed that specific features of the new curriculum - integration of content, requirement for both independent and collaborative learning - were likely to polarise students. The findings suggest that shifting students towards deeper approaches to learning may be a more complex task than previously understood. The authors suggest some ways in which such major curriculum change may be moderated so that all learners are more likely to benefit.