Doctors who believe in a treatment’s effectiveness and therefore display more empathy can influence a patient’s perception of pain through a socially transmitted placebo effect, a US study suggests.

The findings, published in Nature Human Behaviour, highlight the importance of a good bedside manner and have important implications for clinical interactions, the researchers say.

In a simulated clinical interaction, researchers from Dartmouth College in New Hampshire, US, randomly assigned 194 undergraduate students (aged 18-28) to role-play as either a ‘doctor’ or ‘patient’ to test for an interpersonal-expectancy effect, where a person’s behaviour is altered by the expected outcome.

The doctors were given two creams — one they were led to believe had analgesic properties and the other a placebo — to administer to patients after thermal pain stimulation.