Describe your research and the big picture problem or puzzle it addresses.
Over the last 10 years, a series of well-designed laboratory studies using pain induction and healthy meditation practitioners have shown that meditation can be helpful for dealing with pain. When meditators are given the same kind of stimulation and pain is compared before vs. during meditation, meditators typically report either a drop in pain intensity (how strong the pain is), pain unpleasantness (how bothersome the pain is), or both.
This is very exciting because of the potential to handle pain in a drug-free, safe way! However, we don’t yet know HOW the brain does this!
We hypothesized that endogenous opioids might be the neurochemical mechanism by which meditation reduces pain. Endogenous opioids are natural chemicals made by the brain that reduce pain by targeting the same neural pathways as morphine — the brain’s natural morphine. Studies have shown that our brains can reduce pain by releasing endogenous opioids for other psychological reasons such as placebo belief effects, so it was a good guess that meditation could release these chemicals as well.
What did you do?
Electrical pain was induced with randomized, double-blind, cross-over administration of the opioid antagonist Naloxone with 32 healthy, experienced meditation practitioners and a standardized open monitoring meditation.
In other words, meditation practitioners each came into our lab on two different days for two different sessions. In each session, we measured their pain when they were just sitting in a chair doing nothing, and then measured their pain again while they were meditating.
In one session, participants got an IV of normal Saline. Saline is just salt water, and has no effect on pain. In the other session, participants got an IV of high dose Naloxone. Naloxone is a drug that temporarily blocks opioid receptors, thereby stopping endogenous opioids from reducing pain.
This study administered in a double-blind manner, meaning that they didn’t know which day they got Saline and which day they got Naloxone, and the researchers also didn’t know which day they got what drug.
What did you find?
We thought of two possible outcomes:
1. If endogenous opioids are the chemicals the brain uses to reduce pain during meditation, pain would get worse in the session in which we stopped endogenous opioids from reducing pain (compared to the session where participants got Saline).
2. If endogenous opioids are not the chemicals the brain uses to reduce pain during meditation, there would be no effect on pain in the session where we stopped endogenous opioids from reducing pain.
To our surprise, our results fit neither of these predicted patterns! Instead, meditations reduction of pain was ENHANCED during the session where endogenous opioids were turned off! To our knowledge, no study has reported this pattern of results before with high dose Naloxone, despite the fact that high dose Naloxone has been used in pain studies like this for over 30 years!
What are the takeaways?
What could this mean? Well, first, it suggests that endogenous opioids are clearly not the chemical the brain uses to reduce pain during meditation. And second, the best explanation we can think of for Naloxone’s meditation pain relief enhancement is an interaction with another chemical pathway. For example, stopping endogenous opioids from working could make norepinephrine or dopamine’s impact on pain stronger.
Not only does this study suggest something new about meditation, but also new information about how the brain processes pain in general!