8 ms·

Smoking Cannabis Associated with Dopamine Deficits in the Brain

37 points by jrs235 11y ago

erokar 11y ago
Link to abstract:http://www.nature.com/mp/journal/vaop/ncurrent/full/mp201621a.html http://www.nature.com/mp/journal/vaop/ncurrent/full/mp201621... The abstract doesn't really state if they attempted to test the effect of cannabis on dopamine with ongoning chronic use or after abstinence. It seems to be the latter, though, since the users stayed abstinent for 5-7 days before the brain scans. That's a rater short time for the brain to "recover" from chronic cannabis use. It is also worth nothing that they measured dopamine binding by administrating amphetamine.
- aridiculous 11y ago
  Also, I'm having trouble finding what satisfies the condition of 'severe dependence'. Did anyone catch it?
exabrial 11y ago
Sort of off topic... but why is everyone still "smoking" cannabis? Why not vape, edible, etc? I'm fairly certain putting any kind of smoke in your lungs cannot be healthy!
- Alupis 11y ago
  Well, the article/study are asserting the mere consumption of cannabis is the issue, not the method of consumption. Dopamine is a neurotransmitter that plays a key role in the brain’s so-called reward center, and is released in response to pleasurable stimuli like eating cake, having sex, and taking drugs. This is what makes many drugs so addictive (and cake so irresistible), although research suggests that excessive use of these substances causes a dopamine imbalance, with lower concentrations of the chemical being released in parts of the brain such as the striatum. Importantly, dopamine deficits in the striatum have been associated with reduced cognitive performance. Given that THC – the active ingredient in cannabis – is known to stimulate dopamine neurons throughout the brain, lead researcher Anissa Abi-Dargham explained that “it is important to look more closely at the potentially addictive effects of cannabis on key regions of the brain.” But of course, inhaling smoke from anything is not healthy. But that's not to say vaping or edibles are healthy just because they don't contain smoke! You're putting foreign chemicals into your body either way, and according to this study, they all have the same long term negative cognition impacts.
- papul1993 11y ago
  Because that is expensive compared to just buying the plant, grinding it, rolling it up and smoking it?
  - GordonS 11y ago
    nope, vaping and edibles are much more economical - your cannabis goes a lot further
    - ergothus 11y ago
      But the market can change that. In Seattle, for example, when edibles were first legal they were ridiculously priced because of the licensing requirements, and they haven't gotten much better. You can buy the oil and bake your own, but that requires more money and effort up front ($50-$100). Vaping using concentrate is likewise not cheap.
      - exelius 11y ago
        It's also incredibly easy to grow your own. It's called "weed" for a reason; if you threw some seeds in your back garden, in a few months you'd end up with something that would get you high for almost zero effort. And if you grow your own, you end up with plenty of "trim" (plant parts that aren't suited for smoking but still have lots of psychoactive ingredients). Most home growers will cook their trim with butter for a few hours, strain off the plant material, and use that to make edibles. It's not as scientific or consistent as the commercial methods, but it's easy and completely safe.
      - GordonS 11y ago
        > You can buy the oil and bake your own, but that requires more money and effort up front ($50-$100) It doesn't require much money or effort at all. I regularly make small batches of oil using as little as 0.5g of kief. I melt a little coconut oil, dump in the kief (would work with weed too, of course) and cover with tinfoil. Then I bake it at 115C/240F for 27 minutes - cannaoil, done! THC is metabolised into a stronger form, THC-9-COOH, so edibles really make it go further. Plus the effects last several hours instead of the 1-2 when smoking or vaping. > Vaping using concentrate is likewise not cheap. Erm.. you don't have to use concentrates.
- reflexorozy 11y ago
  In places where marijuana is illegal, it's tough to cook your own oil because your neighbors will smell it. There's no access to vaporizer liquid, and the vaporizers that do not need it and actually work are pretty expensive.
- jkaunisv1 11y ago
  Different reasons for different users, but here's a few possible ones: dosage control is really hard with edibles (and they take a while to take effect), vapes are more expensive/slower, can be less portable, and I think the biggest one may be tradition/ritual that people enjoy around smoking. Humans aren't known for making the best decisions for their health :)
- exelius 11y ago
  Edibles kind of suck TBH. Everyone's body digests and metabolizes things at a different rate, so while one brownie may get me absolutely stoned for 4 hours, my friend may need to eat 3 to get the same effect. Also, edibles take anywhere from 30 to 90 minutes to kick in -- you don't get the immediate effect you get from inhaling it. Vapes are better, but the quality varies widely. THC is not water-soluble, so you need a hydrocarbon solvent (usually butane) to extract it and dilute it into enough of a liquid that it won't separate. Those vapes are actually pretty good and hit almost like smoking a pipe, but then again you're breathing in solvents along with it. Also, this type of liquid is close to impossible to make yourself -- at least safely (since it requires subjecting volatile solvents to high pressures and temperature). There are "solvent free" blends that use things like coconut oil, but IMO those vapes don't work nearly as well and give a very thin vapor that is very hard to draw on. For this reason, some people prefer "dabbing" which is basically taking refined THC (in either solid or paste form) and burning it at very high temperatures, then inhaling the smoke. That way you get high without solvents or the majority of the burnt plant material, but a dabbing setup is expensive and it's really only feasible in places where you can easily buy the "wax" (i.e. Colorado). If you mean the hot air vaporizers... they tend to be expensive and use twice as much material as smoking it, plus they don't "hit" like a pipe or bong (you have to inhale for a much longer time to get the same effect).
  - c22 11y ago
    > Also, this type of liquid is close to impossible to make yourself -- at least safely (since it requires subjecting volatile solvents to high pressures and temperature). I built a closed loop (butane retaining) essential oils extractor for around $1500 and I never felt unsafe operating it. There are no high pressures involved, I pull the system to a slight vacuum then flood it with butane to around 15 psi (all my valves, ports, and joints are rated to 300 psi). There are no high temperatures involved either, butane boils at 30.2°F so I just leave the system at room temperature with the gas reclaimer running till all my solvent is back in the cylinder. The largest risk is actually developing a butane leak and flooding the area with an odorless flammable gas, but basic precautions can protect against this.
    - 11y ago
- jbob2000 11y ago
  There's a taste to the smoke that some people like and the highs are very different. I have all options available to me (water pipe, vape, edibles, joint) and I rotate around to keep things interesting. A water pipe (bong) is a great high for about 20mins, then you pretty much fall asleep. Vape takes a long time to get high, it's not as strong, and you fall asleep after 20mins. Edibles take a really long time to hit you, like 2 hours, it comes on very quickly and fades very quickly, but doesn't really knock you out. Joints hit you pretty quick, the high is average, and doesn't really knock you out. So it depends on what you're feeling! Joints are very social, good for smoking with friends. Vapes and bongs get dirty quickly, I don't like using them socially. Edibles are great for novices or when you're going to the movies or something.
  - kafkaesq 11y ago
    You know, if something makes you fall asleep after 20 minutes... then maybe this is your brain's way of telling you -- ever so gently (for now, at least) -- that you're pushing it well past its normal, safe operating parameters? And that perhaps you should start cutting back a bit -- perhaps way back? Being as, if you keep ignoring these signals, and pushing that envelope, eventually your brain will start letting you know in ways that aren't so gentle - or as forgiving.
Alupis 11y ago
It's rather interesting to me, that every time one of these studies or articles is published, people crawl out of the woodwork shouting denials and rejection. People, for some reason, want to cling to this naive idea that cannabis consumption has zero negative effects. Can't we all just accept that it is indeed harmful to your body and brain, especially if used habitually? Continue to use it as you wish, but understand it very well is causing long term harm, just as any other sin-of-choice! Is that really so rejectionable?
- takno 11y ago
  There exists a political climate where any negative effects are seized upon as evidence that cannabis should remain banned, however inapplicable (for example because they are a small study of chronic users after a week's withdrawal). In such circumstances it is often couterproductive to hold nuanced views.
  - DanBC 11y ago
    > In such circumstances it is often couterproductive to hold nuanced views. That's what parent poster is asking for. Any time I post about cannabis on HN i have to include the line "I am strongly in favour of drug legalisation" or tediously predictable replies accusing me of shilling for the government appear. And my position - that for some people smoking large amounts of cannabis is probably a bad idea (especially if they've young; have a history of psychosis; or have a family history of psychosis) - doesn't feel particularly un-nuanced.
    - pc86 11y ago
      I'd be more interested in your nuanced opinions if you weren't a government shill.
      - DanBC 11y ago
        I'm not a government shill, which makes it even more frustrating.
      - 11y ago
madaxe_again 11y ago
Uh, reading the study, smoking cannabis then taking amphetamine causes dopamine deficits, and they don't explore whether this is transient or permanent. I smoke more weed than I probably should, but I had a screwed up dopamine system to start with - the genes don't lie. Actually, on that note, perhaps people with preexisting dopamine deficits are more likely to become heavy cannabis users because it's the only way that they can experience dopamine - going through life with people going "what an achievement! Aren't you proud??" and only being able to reply "meh, I should've done better than first place" or whatever sucks. I can only reflect upon and feel good about what I've done with my life when stoned. I don't have a reward cycle, otherwise - I learned to motivate myself with a punishment cycle instead, and only now am I slowly unlearning it.
- llamataboot 11y ago
  To be fair, amphetamines causing dopamine deficits seems pretty obvious. Anyone that has ever gone on a speed binge (and yes, that time you took adderall for 3 days straight to get some shit done counts) knows that the next days afterwards can be pretty blah. There's dopamine precursors that help, but as with all substances -- what goes up, must come down. Everything in moderation, including moderation.
  - llamataboot 11y ago
    In this case though, it seems like the amphetamines had reduced dopaminergenic effects for chronic cannabis users. Again - lack of motivation is a pretty common anecdotal report of heavy and chronic cannabis use. Moderation.
    - exelius 11y ago
      Lack of motivation is a pretty common reason for prescribing amphetimines as well. Also, I know plenty of counter-examples to the "lazy stoner" stereotype. You just didn't know that the CEO of your company has a stealth grow op in his basement because that's not the kind of thing you advertise. Anecdotally, I would say that regular and heavy cannabis use very common among management consultants and software developers -- and it's hard to remain in those jobs long if you're unable to motivate yourself. But if work is stressful, a few bong rips at the end of the day can be a nice way to relax.
deleted 11y ago
[deleted]
erokar 11y ago
All known drugs of abuse increase dopamine and likewise cause decrease in dopamine during drug withdrawal [1]. Since the participants in the study in question were chronic cannabis users who stayed abstinent 5-7 days before the brain scans [2], it is plausible to attribute the results to the cannabis withdrawal. It would be interesting to see the results of a similar experiment where the subjects were given enough time for their brains to normalize the dopamine receptors (let's say at least a month). My hypotesis is that their dopamine levels would be closer to normal. 1. http://perspectivesinmedicine.cshlp.org/content/2/8/a012229.full http://perspectivesinmedicine.cshlp.org/content/2/8/a012229.... 2. http://www.nature.com/mp/journal/vaop/ncurrent/full/mp201621a.html http://www.nature.com/mp/journal/vaop/ncurrent/full/mp201621...
theboywho 11y ago
"However, the researchers also point out that they “cannot show a causal relationship” between cannabis use and dopamine deficit, explaining that they can’t be sure" Ok thanks bye.
- dang 11y ago
  Please don't post unsubstantive comments to Hacker News. Glib dismissals (like this one) are among the worst forms of this, so please avoid those in particular.
excalibur 11y ago
Let them eat cake!
BFatts 11y ago
The article and the title are wayyy out of parallel. The title says "There is a definite link between cannabis and dopamine levels, and too much will cause a deficit!!" Whereas, in the article it clearly says "Nope, we didn't see any causal effect. The patients could have had a deficit already and we wouldn't know." Are the title, copy, and image editors all different people?

37 points by jrs235 11y ago

Link to abstract:http://www.nature.com/mp/journal/vaop/ncurrent/full/mp201621a.html http://www.nature.com/mp/journal/vaop/ncurrent/full/mp201621... The abstract doesn't really state if they attempted to test the effect of cannabis on dopamine with ongoning chronic use or after abstinence. It seems to be the latter, though, since the users stayed abstinent for 5-7 days before the brain scans. That's a rater short time for the brain to "recover" from chronic cannabis use. It is also worth nothing that they measured dopamine binding by administrating amphetamine.

aridiculous 11y ago
Also, I'm having trouble finding what satisfies the condition of 'severe dependence'. Did anyone catch it?

exabrial 11y ago

Sort of off topic... but why is everyone still "smoking" cannabis? Why not vape, edible, etc? I'm fairly certain putting any kind of smoke in your lungs cannot be healthy!

Alupis 11y ago
Well, the article/study are asserting the mere consumption of cannabis is the issue, not the method of consumption. Dopamine is a neurotransmitter that plays a key role in the brain’s so-called reward center, and is released in response to pleasurable stimuli like eating cake, having sex, and taking drugs. This is what makes many drugs so addictive (and cake so irresistible), although research suggests that excessive use of these substances causes a dopamine imbalance, with lower concentrations of the chemical being released in parts of the brain such as the striatum. Importantly, dopamine deficits in the striatum have been associated with reduced cognitive performance. Given that THC – the active ingredient in cannabis – is known to stimulate dopamine neurons throughout the brain, lead researcher Anissa Abi-Dargham explained that “it is important to look more closely at the potentially addictive effects of cannabis on key regions of the brain.” But of course, inhaling smoke from anything is not healthy. But that's not to say vaping or edibles are healthy just because they don't contain smoke! You're putting foreign chemicals into your body either way, and according to this study, they all have the same long term negative cognition impacts.
papul1993 11y ago
Because that is expensive compared to just buying the plant, grinding it, rolling it up and smoking it?
- GordonS 11y ago
  nope, vaping and edibles are much more economical - your cannabis goes a lot further
  - ergothus 11y ago
    But the market can change that. In Seattle, for example, when edibles were first legal they were ridiculously priced because of the licensing requirements, and they haven't gotten much better. You can buy the oil and bake your own, but that requires more money and effort up front ($50-$100). Vaping using concentrate is likewise not cheap.
    - exelius 11y ago
      It's also incredibly easy to grow your own. It's called "weed" for a reason; if you threw some seeds in your back garden, in a few months you'd end up with something that would get you high for almost zero effort. And if you grow your own, you end up with plenty of "trim" (plant parts that aren't suited for smoking but still have lots of psychoactive ingredients). Most home growers will cook their trim with butter for a few hours, strain off the plant material, and use that to make edibles. It's not as scientific or consistent as the commercial methods, but it's easy and completely safe.
    - GordonS 11y ago
      > You can buy the oil and bake your own, but that requires more money and effort up front ($50-$100) It doesn't require much money or effort at all. I regularly make small batches of oil using as little as 0.5g of kief. I melt a little coconut oil, dump in the kief (would work with weed too, of course) and cover with tinfoil. Then I bake it at 115C/240F for 27 minutes - cannaoil, done! THC is metabolised into a stronger form, THC-9-COOH, so edibles really make it go further. Plus the effects last several hours instead of the 1-2 when smoking or vaping. > Vaping using concentrate is likewise not cheap. Erm.. you don't have to use concentrates.
reflexorozy 11y ago
In places where marijuana is illegal, it's tough to cook your own oil because your neighbors will smell it. There's no access to vaporizer liquid, and the vaporizers that do not need it and actually work are pretty expensive.
jkaunisv1 11y ago
Different reasons for different users, but here's a few possible ones: dosage control is really hard with edibles (and they take a while to take effect), vapes are more expensive/slower, can be less portable, and I think the biggest one may be tradition/ritual that people enjoy around smoking. Humans aren't known for making the best decisions for their health :)
exelius 11y ago
Edibles kind of suck TBH. Everyone's body digests and metabolizes things at a different rate, so while one brownie may get me absolutely stoned for 4 hours, my friend may need to eat 3 to get the same effect. Also, edibles take anywhere from 30 to 90 minutes to kick in -- you don't get the immediate effect you get from inhaling it. Vapes are better, but the quality varies widely. THC is not water-soluble, so you need a hydrocarbon solvent (usually butane) to extract it and dilute it into enough of a liquid that it won't separate. Those vapes are actually pretty good and hit almost like smoking a pipe, but then again you're breathing in solvents along with it. Also, this type of liquid is close to impossible to make yourself -- at least safely (since it requires subjecting volatile solvents to high pressures and temperature). There are "solvent free" blends that use things like coconut oil, but IMO those vapes don't work nearly as well and give a very thin vapor that is very hard to draw on. For this reason, some people prefer "dabbing" which is basically taking refined THC (in either solid or paste form) and burning it at very high temperatures, then inhaling the smoke. That way you get high without solvents or the majority of the burnt plant material, but a dabbing setup is expensive and it's really only feasible in places where you can easily buy the "wax" (i.e. Colorado). If you mean the hot air vaporizers... they tend to be expensive and use twice as much material as smoking it, plus they don't "hit" like a pipe or bong (you have to inhale for a much longer time to get the same effect).
- c22 11y ago
  > Also, this type of liquid is close to impossible to make yourself -- at least safely (since it requires subjecting volatile solvents to high pressures and temperature). I built a closed loop (butane retaining) essential oils extractor for around $1500 and I never felt unsafe operating it. There are no high pressures involved, I pull the system to a slight vacuum then flood it with butane to around 15 psi (all my valves, ports, and joints are rated to 300 psi). There are no high temperatures involved either, butane boils at 30.2°F so I just leave the system at room temperature with the gas reclaimer running till all my solvent is back in the cylinder. The largest risk is actually developing a butane leak and flooding the area with an odorless flammable gas, but basic precautions can protect against this.
  - 11y ago
jbob2000 11y ago
There's a taste to the smoke that some people like and the highs are very different. I have all options available to me (water pipe, vape, edibles, joint) and I rotate around to keep things interesting. A water pipe (bong) is a great high for about 20mins, then you pretty much fall asleep. Vape takes a long time to get high, it's not as strong, and you fall asleep after 20mins. Edibles take a really long time to hit you, like 2 hours, it comes on very quickly and fades very quickly, but doesn't really knock you out. Joints hit you pretty quick, the high is average, and doesn't really knock you out. So it depends on what you're feeling! Joints are very social, good for smoking with friends. Vapes and bongs get dirty quickly, I don't like using them socially. Edibles are great for novices or when you're going to the movies or something.
- kafkaesq 11y ago
  You know, if something makes you fall asleep after 20 minutes... then maybe this is your brain's way of telling you -- ever so gently (for now, at least) -- that you're pushing it well past its normal, safe operating parameters? And that perhaps you should start cutting back a bit -- perhaps way back? Being as, if you keep ignoring these signals, and pushing that envelope, eventually your brain will start letting you know in ways that aren't so gentle - or as forgiving.

Alupis 11y ago

It's rather interesting to me, that every time one of these studies or articles is published, people crawl out of the woodwork shouting denials and rejection. People, for some reason, want to cling to this naive idea that cannabis consumption has zero negative effects. Can't we all just accept that it is indeed harmful to your body and brain, especially if used habitually? Continue to use it as you wish, but understand it very well is causing long term harm, just as any other sin-of-choice! Is that really so rejectionable?

takno 11y ago
There exists a political climate where any negative effects are seized upon as evidence that cannabis should remain banned, however inapplicable (for example because they are a small study of chronic users after a week's withdrawal). In such circumstances it is often couterproductive to hold nuanced views.
- DanBC 11y ago
  > In such circumstances it is often couterproductive to hold nuanced views. That's what parent poster is asking for. Any time I post about cannabis on HN i have to include the line "I am strongly in favour of drug legalisation" or tediously predictable replies accusing me of shilling for the government appear. And my position - that for some people smoking large amounts of cannabis is probably a bad idea (especially if they've young; have a history of psychosis; or have a family history of psychosis) - doesn't feel particularly un-nuanced.
  - pc86 11y ago
    I'd be more interested in your nuanced opinions if you weren't a government shill.
    - DanBC 11y ago
      I'm not a government shill, which makes it even more frustrating.
    - 11y ago

madaxe_again 11y ago

Uh, reading the study, smoking cannabis then taking amphetamine causes dopamine deficits, and they don't explore whether this is transient or permanent. I smoke more weed than I probably should, but I had a screwed up dopamine system to start with - the genes don't lie. Actually, on that note, perhaps people with preexisting dopamine deficits are more likely to become heavy cannabis users because it's the only way that they can experience dopamine - going through life with people going "what an achievement! Aren't you proud??" and only being able to reply "meh, I should've done better than first place" or whatever sucks. I can only reflect upon and feel good about what I've done with my life when stoned. I don't have a reward cycle, otherwise - I learned to motivate myself with a punishment cycle instead, and only now am I slowly unlearning it.

llamataboot 11y ago
To be fair, amphetamines causing dopamine deficits seems pretty obvious. Anyone that has ever gone on a speed binge (and yes, that time you took adderall for 3 days straight to get some shit done counts) knows that the next days afterwards can be pretty blah. There's dopamine precursors that help, but as with all substances -- what goes up, must come down. Everything in moderation, including moderation.
- llamataboot 11y ago
  In this case though, it seems like the amphetamines had reduced dopaminergenic effects for chronic cannabis users. Again - lack of motivation is a pretty common anecdotal report of heavy and chronic cannabis use. Moderation.
  - exelius 11y ago
    Lack of motivation is a pretty common reason for prescribing amphetimines as well. Also, I know plenty of counter-examples to the "lazy stoner" stereotype. You just didn't know that the CEO of your company has a stealth grow op in his basement because that's not the kind of thing you advertise. Anecdotally, I would say that regular and heavy cannabis use very common among management consultants and software developers -- and it's hard to remain in those jobs long if you're unable to motivate yourself. But if work is stressful, a few bong rips at the end of the day can be a nice way to relax.

deleted 11y ago

[deleted]

erokar 11y ago

All known drugs of abuse increase dopamine and likewise cause decrease in dopamine during drug withdrawal [1]. Since the participants in the study in question were chronic cannabis users who stayed abstinent 5-7 days before the brain scans [2], it is plausible to attribute the results to the cannabis withdrawal. It would be interesting to see the results of a similar experiment where the subjects were given enough time for their brains to normalize the dopamine receptors (let's say at least a month). My hypotesis is that their dopamine levels would be closer to normal. 1. http://perspectivesinmedicine.cshlp.org/content/2/8/a012229.full http://perspectivesinmedicine.cshlp.org/content/2/8/a012229.... 2. http://www.nature.com/mp/journal/vaop/ncurrent/full/mp201621a.html http://www.nature.com/mp/journal/vaop/ncurrent/full/mp201621...

theboywho 11y ago

"However, the researchers also point out that they “cannot show a causal relationship” between cannabis use and dopamine deficit, explaining that they can’t be sure" Ok thanks bye.

dang 11y ago
Please don't post unsubstantive comments to Hacker News. Glib dismissals (like this one) are among the worst forms of this, so please avoid those in particular.

excalibur 11y ago

Let them eat cake!

BFatts 11y ago

The article and the title are wayyy out of parallel. The title says "There is a definite link between cannabis and dopamine levels, and too much will cause a deficit!!" Whereas, in the article it clearly says "Nope, we didn't see any causal effect. The patients could have had a deficit already and we wouldn't know." Are the title, copy, and image editors all different people?