RESUMO
CONTEXT: Time pressure has been implicated in the suboptimal diagnostic performance of doctors and in increases in diagnostic errors. However, the reasons underlying these effects are not clear. The aim of this study was to investigate the influence of time pressure on physicians' diagnostic accuracy and to explore the mediating effects of perceived stress (emotional pathway) and number of plausible diagnostic hypotheses (cognitive pathway) on the proposed relationship. METHODS: We conducted a randomised controlled experiment. A total of 75 senior internal medicine residents completed eight written clinical cases under conditions with (n = 40) or without (n = 35) time pressure. They were then asked to: (i) rate the overall stress experienced, and (ii) write down any alternative hypotheses they had thought of when diagnosing the cases. In a post hoc analysis, a mediation path analysis was performed to test the causal relationships between time pressure, perceived stress and number of alternative diagnoses. RESULTS: Participants who were under time pressure spent less time diagnosing the cases (85.54 seconds versus 181.81 seconds; p< 0.001) and had a lower mean diagnostic accuracy score (0.44 versus 0.53; p = 0.01). In addition, they reported more stress (5.80 versus 4.69; p = 0.01) and generated fewer plausible tentative hypotheses (0.37 versus 0.51; p = 0.01). Two path coefficients were found to be statistically significant; the first path coefficient referred to the relationship between time pressure and perceived stress (standardised ß = 0.25, p = 0.029), and the second negative path coefficient referred to the relationship between time pressure and number of plausible alternative hypotheses (standardised ß = -0.32, p< 0.01). CONCLUSIONS: Time pressure adversely influences physicians' diagnostic accuracy by increasing their stress response and reducing the number of plausible hypotheses as mediators.
