OBJECTIVE: To examine the influence of addiction risk (substance abuse history [SAH]) and pain relief (PR) on nursing and non-nursing students’ perceptions of pain in a postoperative vignette patient.METHODS: Using a 2×2 design, the independent variables SAH (present/+, absent/–) and PR (adequate, little) were varied systematically to produce four vignettes. Participants were randomly assigned to receive one of the four vignettes that described a 45-year-old man after a total hip replacement. Participants rated the vignette patient’s experienced and reported pain intensity (PI) on a 0 mm to 100 mm visual analogue scale and addiction risk on a 0 mm to 100 mm visual analogue scale. A pain congruence (PC) score was calculated (PC = reported PI – experienced PI), and was interpreted as congruent (±2 mm) or incongruent (+2 mm to +100 mm for expected pain over-reporting; −2 mm to −100 mm for expected pain under-reporting).RESULTS: Responses from undergraduate nursing (n=89) and non-nursing (n=88) students were analyzed. The estimated addiction risk was significantly lower in nursing (14% to 45%) versus non-nursing students (50%). Nursing students’ mean PC scores were not significantly altered by SAH alone. Expectations of pain over-reporting were observed under conditions of SAH+/adequate PR, but not SAH+/little PR. In non-nursing students, SAH and PR were significant and independent factors influencing mean PC scores in the direction of pain over-reporting.CONCLUSION: Under most conditions, nursing students expected pain under-reporting by the postoperative vignette patient. However, nursing students did expect pain to be over-reported when addiction risk was high and PR was adequate. These data suggest that nursing students’ expectations regarding pain over- and under-reporting were sensitive to perceptions of addiction risk, but involved additional factors (eg, level of PR).