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Doctors' expectations of treatment efficacy may alter patient reaction to treatment
Health care providers’ expectations for the effectiveness of a treatment may affect clinical interactions and engender a “socially transmitted placebo effect,” according to results of a study published in Nature Human Behaviour that simulated a clinical interaction.
“Though modern western medicine has made extraordinary advances, all treatments are still delivered in the context of a trusting relationship between the patient and provider,” Luke Chang, PhD, assistant professor in the department of psychological and brain sciences at Dartmouth College, told Healio Psychiatry. “Aspects of this relationship can have substantial impacts on treatment outcomes. This study is one of the first attempts to quantify the magnitude of how a provider’s belief in the effectiveness of a treatment might impact treatment outcomes.”
Chang and colleagues recruited 194 college students who were assigned to play the role of either a “patient” or a “doctor.” Participants in the doctor role were told that they would be administering a transient receptor potential-channel blocker with analgesic effects for thermal pain, referred to as thermedol, or a control cream, both intended to alleviate thermal pain. However, both creams were a placebo — Vaseline.
The placebo was applied to patients’ arms under the guise of two separate creams, and then 116.6 degrees Fahrenheit of thermal heat was applied following each application. Patients were instructed to assess the effectiveness of both applications. The researchers conditioned the doctors to believe that the thermedol cream was more effective than the control, and the patient was given no indication of which cream was supposed to be more effective.
Using GoPro cameras, the researchers recorded both patients’ and doctors’ facial expressions during the heat application in relation to both creams. They then used a machine-learning pain model to determine whether patients displayed less pain through their facial expressions when receiving the thermedol treatment.
Patients reported a significant increase in beliefs of effectiveness of the thermedol compared with the control treatment (P = .03), as well as experiencing less pain. Chang and colleagues suggested that the doctors displayed different pain facial expressions while delivering the thermedol vs. control because they were conditioned to believe thermedol was the only effective treatment. They tested this hypothesis using a pain expression model and observed that doctors, similarly to the patients, experienced less pain facial expression behavior while patients received stimulation with the thermedol vs. the control (P = .03). Patients seemed to notice the behavioral change in the doctors and described them as more empathetic when delivering thermedol compared with the control (P = .007).
The researchers also conducted two other iterations of the study, switching the order in which the creams were administered to rule out the possibility that the association between doctors’ expectations about treatment efficacy and patients’ experiences of pain was not from habituation or extinction.
“This work has significant implications for clinical research and practice,” Chang said. “In psychotherapy research, treatments can never be administered double blind and it has been estimated that much of the treatment outcome variance can be explained by ‘nonspecific factors,’ such as the provider’s expectations and the therapeutic relationship. In modern medical training, 'soft skills' in how to build relationships have received considerably less attention than training in ‘evidence-based’ practice. We hope that this work will inspire a more careful examination of how these soft skills might be trained to improve the magnitude of treatment outcomes.” – by Joe Gramigna
Disclosures: The authors report no relevant financial disclosures.