Both real patient interactions and SP interactions are considered indispensable to undergraduate medical education. Each encounter has unique strengths and weaknesses from the perspectives of students. On the basis of strengths and weaknesses that were identified, suggestions were made for the use of real patients and SPs in undergraduate medical education.

The aim of this review was to identify the strengths and weaknesses of the roles of real and simulated patients in undergraduate medical education. The literature was reviewed in relation to four patient roles: real patients as educational "resource" (passive role), real patients as teachers (active role), and simulated patients as educational resource and teachers. Each of the four patient roles was found to have specific advantages and disadvantages from the perspectives of teachers, students, and patients. For example, advantages of real patients as educational resource were patient-centered learning and high patient satisfaction. Disadvantages were their limited availability and the variability in learning experiences among students. Despite the considerable amount of literature we found, many gaps in knowledge about patient roles in medical education remain and should be addressed by future studies.

There is a need for research on the additional value of the incognito standardised patient methodology and for a consensus on how to report on accuracy and consistency of standardised patients.

There appear to be no clear standards with regard to effective feedback training for SPs. Furthermore, the processes by which feedback is provided by SPs and the selection of domain(s) in which SPs give feedback often seem to lack a solid scientific basis. Suggestions for further research are provided.

Students consider authenticity an important advantage of real patients. Their difficult recruitment is an important disadvantage, however, SPs have important advantages compared with real patients--for example, their feedback. The choice of real patient contacts or SP contacts for medical education depends on factors like the phase of the curriculum and the aim of the encounter.

An unexpectedly high number of SPs reported symptoms. Fortunately, the symptoms were relatively mild (2.2 on a 5-point scale). Future studies should address the connection between work as an SP and symptoms, and measures should be taken to prevent and treat the symptoms. Debriefing sessions might play a role in this respect.

Although the SPs were found to experience negative effects caused by playing patient roles, the frequency and intensity of the negative effects were minor. The focus group discussions led to various suggestions for measures to reduce the impact of simulation.

Generally, students and teachers were satisfied with the quality of the role playing and feedback provided by the adolescent SPs. The adolescent SPs experienced no negative effects related to their performance, which confirms earlier findings among adolescent standardized patients.