Placebos reduce stress, anxiety and depression, even when people know they are placebos

Researchers recruited participants who had experienced prolonged stress due to the COVID-19 pandemic for a two-week randomized controlled trial. Half of the participants were randomly assigned to a non-deceptive placebo group and half to the control group that took no pills. Participants interacted with a researcher online through four virtual sessions on Zoom. Those in the non-deceptive placebo group received information about the placebo effect and were mailed placebo pills along with instructions on how to take them.

The study, published in Applied Psychology:Health and wellnessThe untreated group was found to show significant reductions in stress, anxiety and depression in just two weeks compared to the untreated control group. Participants also reported that the untreated placebos were easy to use, not cumbersome and appropriate for the situation.

“Long-term exposure to stress can impair a person’s ability to manage emotions and lead to significant long-term mental health problems, so we are excited to see that an intervention that requires minimal effort can yield significant benefits,” said Jason Moser, co-author of the study and a professor in the Department of Psychology at MSU. “This minimal burden makes nondeceptive placebos an attractive intervention for those experiencing significant stress, anxiety and depression.”

Researchers are especially hopeful about the possibility that health care providers could remotely administer non-deceptive placebos.

“This ability to administer non-deceptive placebos remotely dramatically increases the potential for scalability,” said Darwin Guevarra, co-author of the study and a postdoctoral scholar at the University of California, San Francisco. “Non-deceptive placebos administered remotely have the potential to help people struggling with mental health issues who might not otherwise have access to traditional mental health services.”