Non-deceptive placebos have analgesic effects regulated by endogenous opioids

It’s been reported that placebo effect can be induced without the need for deceiving the patient, but rather simply the act of performing the procedure while explaining that it’s fake (Kaptchunk, 2018) which would hugely facilitate their use in clinical trials.

Closed-label (deceiving) placebos act through endogenous opioids, so researchers wanted to see if open-label (non-deceiving) placebos acted through a similar mechanism.

By adding a dose of opioid inhibitor naloxone along with the open-label placebo, the analgesic effects are reversed.

These findings suggest that open-label placebos work through a similar mechanism to close-label placebos.


Fabrizio Benedetti, Aziz Shaibani, Claudia Arduino, Wilma Thoen.