24 December 2012

Marijuana as a "pain distracter"

To determine exactly how cannabis relieves pain, a group of Oxford researchers used healthy volunteers, an MRI machine and doses of THC, the active ingredient in marijuana. Their findings, published today in the journal Pain, suggest something counterintuitive: that the drug doesn’t so much reduce pain as make the same level of pain more bearable.

“Cannabis does not seem to act like a conventional pain medicine,” Michael Lee, an Oxford neuroscientist and lead author of the paper, said in a statement. “Brain imaging shows little reduction in the brain regions that code for the sensation of pain, which is what we tend to see with drugs like opiates. Instead, cannabis appears to mainly affect the emotional reaction to pain in a highly variable way.” 

This indicates that marijuana doesn’t function as a pain killer as much as a pain distracter: Objectively, levels of pain remain the same for someone under the influence of THC, but it simply bothers the person less. It’s difficult to draw especially broad conclusions from a study with a sample size of just 12 participants, but the results were still surprising. 
From at the Smithsonian's Surprising Science blog.

8 comments:

  1. So, it works kind of like nitrous oxide. "Hey, that hurts. Isn't that funny? Ha ha ha!"

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  2. "Objectively, levels of pain remain the same for someone under the influence of THC, but it simply bothers the person less."

    That seems conceptually impossible to me. If pain A bothers me less than pain B, then they cannot be "objectively" the same levels of pain. Am I missing something here?

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    1. Finzent:

      Think of the pain suffered from say, a stubbed toe, and from a broken bone. One is far more intense then the other. A person suffering from a broken bone would still feel the same amount of pain, but would be bothered by it less, perhaps as if they had only suffered a stubbed toe. The total amount of pain would remain the same (a broken bone), but the bother of it would be greatly reduced.

      Or at least that's how it would seem to me

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    2. I read that and related to it as the experience when you cut or smash yourself somewhere you have not actually looked at yet. (Why does it always hurt more after you have looked at it?!?) Perhaps when focused on the pain it is vivid and awful but then thoughts of 'munching on Twinkies', 'free love', and/or 'how amazing a double rainbow is' come to the front of one's attention and the pain is forgotten?

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  3. Funny, that's how my husband feels about opiates, they don't really help the pain much, but he doesn't care as much, and can sleep a bit. This from when he smashed his elbow, and two subsequent surgeries, with therapy sessions. And it's not that uncommon that morphines & derivatives just don't work for some people, only causing lethargy and nausea - having little effect on pain.

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  4. I'm with Zhoen - I had oral surgery once - unbelievable pain, I couldn't think of anything other than how much it hurt. I had codeine as a pain medication. The instructions were to take one tablet every 4 hours. I think it was about after the 4th one in two hours that I stopped caring. The pain was exactly the same but I didn't care anymore because I was sooooo high.

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  5. In his excellent essay "Consider the lobster", David Foster Wallace discusses whether there is a distinction between "pain" and "suffering", and whether suffering includes an emotional component and different (higher) brain functions. To oversimplify, pain=objective, suffering=subjective.

    Written for Gourmet magazine, of all things: http://www.gourmet.com/magazine/2000s/2004/08/consider_the_lobster

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  6. The study sounds correct to me. When I was a kid, my older stepbrother would get me stoned, then punch and kick me. Even though I couldn't do anything but laugh, the pain was still quite real.

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