Growth of knowledge in psychiatry and behavioural sciences in a problem-based learning curriculum.

Purpose: To evaluate the effectiveness of undergraduate medical education in the domains of psychiatry and behavioural sciences, we examined the growth of knowledge in those disciplines in a 6-year, problem-based learning (PBL) curriculum. Psychiatry and behavioural sciences are taught in the 4 preclinical years and in the psychiatric clerkship. The integrative nature of this PBL curriculum led us to hypothesise that the knowledge growth curves for these disciplines are similar and show a steady upward trend throughout the curriculum.
Methods: All items pertaining to psychiatry and behavioural sciences in the progress tests administered in the period from September 1993 through May 2001 were identified. For those items, the percentage of correct scores in the 6 year groups were considered a multivariate observation reflecting knowledge growth across the 6-year programme.
Results: Knowledge growth for psychiatry and behavioural sciences increased significantly, from 12% to 59% and from 28% to 60%, respectively, between Year 1 and the end of Year 6. Apparently, students know more about behavioural sciences than about psychiatry when they enter medical school, but this difference vanishes in the last 2 years of training. Moreover, the growth curves for psychiatry and behavioural sciences started to level off after Years 3 and 4, respectively, with no additional significant growth in any of the later years.
Conclusions: Psychiatry and behavioural sciences showed different patterns of knowledge growth and the 2 growth curves levelled off in Years 5 through 6. Because a student-centred, horizontally and vertically integrated PBL curriculum is aimed at effecting steady growth in knowledge in all disciplines, the slowdown in growth in the later years was among the reasons for initiating a major curricular innovation in 2001.