Influence of Psychiatric or Social Backgrounds on Clinical Decision Making: a Randomized, Controlled Multi-centre Study

Background: Frequent and repeated visits from patients with mental illness or free medical care recipients may elicit physicians' negative emotions and influence their clinical decision making. This study investigated the impact of the psychiatric or social background of such patients on physicians' decision making about whether to offer recommendations for further examinations and whether they expressed an appropriate disposition toward the patient.

Methods: A randomized, controlled multi-centre study of residents in transitional, internal medicine, or emergency medicine was conducted in five hospitals. Upon randomization, participants were stratified by gender and postgraduate year, and they were allocated to scenario set 1 or 2. They answered questions pertaining to decision-making based on eight clinical vignettes. Half of the eight vignettes presented to scenario set 1 included additional patient information, such as that the patient had a past medical history of schizophrenia or that the patient was a recipient of free care who made frequent visits to the doctor (biased vignettes). The other half included no additional information (neutral vignettes). For scenario set 2, the four biased vignettes presented to scenario set 1 were neutralized, and the four neutral vignettes were rendered biased by providing additional information. After reading, participants answered decision-making questions regarding diagnostic examination, interventions, or patient disposition. The primary analysis was a repeated-measures ANOVA on the mean management accuracy score, with patient background information as a within-subject factor (no bias, free care recipients, or history of schizophrenia).

Results: A total of 207 questionnaires were collected. Repeated-measures ANOVA showed that additional background information had influence on mean accuracy score (F(7, 206) = 13.84, p <  0.001 partial η2 = 0.063). Post hoc pairwise multiple comparison test, Sidak test, showed a significant difference between schizophrenia and no bias condition (p <  0.05). The ratings for patient likability were lower in the biased vignettes compared to the neutral vignettes, which was associated with the lower utilization of medical resources by the physicians.

Conclusions: Additional background information on past medical history of schizophrenia increased physicians' mistakes in decision making. Patients' psychiatric backgrounds should not bias physicians' decision-making. Based on these findings, physicians are recommended to avoid being influenced by medically unrelated information.