Hi Rachael, thank you so much for your feedback and for sharing these links. I checked them all out and listened to the podcast interview with Nutt and Badiani. My understanding, after reading and listening to them, is that there have been studies in which heroin was found to produce a reward mechanism without causing a release in dopamine. This makes sense to me. However, I do not see how this data would necessarily mean that heroin is *not* dopaminergic. Rather, it suggests that heroin exhibits reward mechanism activity on receptors in addition to dopamine. Due to the abundance of data which shows that heroin does produce a dopamine response, I think a more nuanced understanding of the data proposed by Nutt, Adiani, et. al is appropriate. Just because one thing is true does not mean it's opposite is not true. It's an old logical fallacy that i forget the name for off the top of my head.
What I mean is this: considering the data shared by you plus the other data I've read about heroin, it seems most accurate to say that heroin produces reward mechanism responses *both* thru dopamine *and* through other receptors. the both/and factor is key. reducing disparate data into either/or arguments is something I generally avoid. the both/and approach is supported if we further examine the specific details of the studies cited by Nutt and Adiani.
For example, in one of the studies done by Nutt and his team, then cited again by him elsewhere, all of the patients in the study (who exhibited no increased dopamine activity after receiving heroin) were using maintenance drugs during the course of the study. They all were on methadone or buprenorphine which Nutt even admits in the article may be a factor affecting the observed results.
In another study, an additional drug was used to block the activity of dopamine receptors during heroin administration. So of course a dopamine response won't be shown--it is being chemically suppressed with the other drug. To me, this does not mean that heroin *never* acts on dopamine, it means that heroin produces its reward mechanism through other receptors *in addition to* dopamine.
Ketamine has this quality--it affects a plethora of receptors, but precisely which depend on the dose, the person, and other factors.
In short, I accept the data you've shared. Clearly heroin can produce a reward mechanism even when dopamine is not involved. But those particular studies do not prove that heroin is more generally not dopaminergic. Even Nutt himself doesn't pronounce this as fact; he merely speculates that it may be a possibility.
Thanks as always for reading and for your feedback! :)
An error: heroin is NOT dopaminergic! The “dopamine theory of addiction” was developed from studies only done on stimulants and when the studies were repeated on opioids, a funny thing was discovered: 1987 pubmed.ncbi.nlm.nih.gov/3032655/ 2011 ncbi.nlm.nih.gov/pmc/articles/P… 2017 core.ac.uk/reader/2994551…
Sorry, 2nd & 3rd links weren’t working, here they are: 2011: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3721140/ 2017: https://core.ac.uk/reader/29945513?utm_source=linkout
Here’s a good podcast about this with David Nutt: https://open.spotify.com/episode/30DjSl8Bdj8tHbTIs76XhM?si=e9v2Z0GqTxGZSuC4DlWNig
Hi Rachael, thank you so much for your feedback and for sharing these links. I checked them all out and listened to the podcast interview with Nutt and Badiani. My understanding, after reading and listening to them, is that there have been studies in which heroin was found to produce a reward mechanism without causing a release in dopamine. This makes sense to me. However, I do not see how this data would necessarily mean that heroin is *not* dopaminergic. Rather, it suggests that heroin exhibits reward mechanism activity on receptors in addition to dopamine. Due to the abundance of data which shows that heroin does produce a dopamine response, I think a more nuanced understanding of the data proposed by Nutt, Adiani, et. al is appropriate. Just because one thing is true does not mean it's opposite is not true. It's an old logical fallacy that i forget the name for off the top of my head.
What I mean is this: considering the data shared by you plus the other data I've read about heroin, it seems most accurate to say that heroin produces reward mechanism responses *both* thru dopamine *and* through other receptors. the both/and factor is key. reducing disparate data into either/or arguments is something I generally avoid. the both/and approach is supported if we further examine the specific details of the studies cited by Nutt and Adiani.
For example, in one of the studies done by Nutt and his team, then cited again by him elsewhere, all of the patients in the study (who exhibited no increased dopamine activity after receiving heroin) were using maintenance drugs during the course of the study. They all were on methadone or buprenorphine which Nutt even admits in the article may be a factor affecting the observed results.
In another study, an additional drug was used to block the activity of dopamine receptors during heroin administration. So of course a dopamine response won't be shown--it is being chemically suppressed with the other drug. To me, this does not mean that heroin *never* acts on dopamine, it means that heroin produces its reward mechanism through other receptors *in addition to* dopamine.
Ketamine has this quality--it affects a plethora of receptors, but precisely which depend on the dose, the person, and other factors.
In short, I accept the data you've shared. Clearly heroin can produce a reward mechanism even when dopamine is not involved. But those particular studies do not prove that heroin is more generally not dopaminergic. Even Nutt himself doesn't pronounce this as fact; he merely speculates that it may be a possibility.
Thanks as always for reading and for your feedback! :)