A new Swedish study on rats suggests that there is a physiological reality behind the idea that relatively innocuous cannabis may act like a gateway drug, leading on to heavier drugs.

Soon-to-be-graduating doctoral candidate Maria Ellgren of Karolinska Institutitet has documented a significantly greater interest in self-administered heroin among adult rats that were dosed with cannabis in the womb or during adolescence. Their brains exhibited changes in parts linked to pleasure and rewards. However, they were not more interested than non-stoner rats in central stimulants such as amphetamine.

I’m a pro-legalisation non-user (indeed, a tee-totaller), and I find this research interesting although unsurprising. Assuming that the results can be extrapolated to humans, it gives rise to a number of further questions.

  • Does alcohol have similar effects on the brain, thus also acting as a gateway drug?
  • Most cannabis users do not graduate to heavier drugs. What factors decide? Social or physiological ones, or simply the cannabis dosage involved?

Prohibition era USA with its gangster wars demonstrates that prohibiting a popular recreational drug creates more problems than it solves. There seem to be social mechanisms preventing a truly destructive one such as heroin from becoming popular. I believe that the money spent on enforcing prohibition would be better used in teaching the risks and treating addicts.

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Comments

  1. #1 Tony P
    February 9, 2007

    You know, I’m getting tired of ONDCP sponsored “studies” that seek to prove such and such about such and such.

    And last I checked, a rat isn’t the same as a human being. Sure we’re both mammals and all, but there are definite physiological differences.

    I also heard a charming ad on the radio today about ’420′. It’s code for marijuana and in the ad they spouted propaganda like increased risk of lung cancer despite studies that show that components of marijuana actually suppress tumor formation in the lung.

    Legalize it, tax it. I say it’s no worse than alcohol.

  2. #2 crimsongirl
    February 9, 2007

    “Prohibition era USA with its gangster wars demonstrates that prohibiting a popular recreational drug creates more problems than it solves.”

    I wonder if that is true. It is certainly the common wisdom, accepted fact. But I wonder if anyone has done any serious study of the question.

    Marijuana is somewhat different than alcohol in that it has not been legal in the living memory. Alcohol was very heavily used in the late 1800s and early 1900s and then Prohibition asked people who drank to give it up. If marijuana is legalized, many people who have never tried it will give it a try. Most of these will not get into any trouble, of course, but some will.

  3. #3 peter
    February 9, 2007

    I was under the impression that marijuana became illegal around 1937?

    this may be a biased account…

  4. #4 whitewhale
    February 9, 2007

    I believe that money spent on teaching the risks and treating addicts is better used than enforcing prohibition.

    Prohibition cannot possibly be better than individuals deciding for themselves.

    Just imagine — the laughable policy of prohibition when there is a drug store on every corner.

  5. #5 Martin R
    February 10, 2007

    Cannabis is one of those issues where it’s hard to get objective information. The stoners insist that it’s all beneficial, their opponents will tell you that it’s the first step on the road to perdition and disease.

    I think it can be said confidently that cannabis is used regularly by a large percentage of the USA’s population. And though that country does have its serious problems, I don’t think many would argue that they are due mainly to cannabis. From my perspective, it seems that the US’s political woes are actually due primarily to conservative groups that incidentally oppose cannabis use.

    No recreational drug does the brain only good. But many feel that a glass of fine whiskey after Saturday dinner, or a good cigar at festive occasions, or a joint every now and then, confers benefits that outweigh the health risks. All in moderation.

    The Swedes, like the English, almost drank themselves to death in the 18th and 19th centuries. We protect ourselves against this societal malaise by taxing liquor heavily. I think we should do likewise with cannabis. It makes a lot of people happy, it kills noone, so we really shouldn’t waste the tax payers’ money combating it. Let’s make tax money off of it instead and separate it socially from debilitating hard drugs.

  6. #6 Torbjörn Larsson
    February 10, 2007

    But many feel that a glass of fine whiskey after Saturday dinner, or a good cigar at festive occasions, or a joint every now and then, confers benefits that outweigh the health risks.

    Or, in the case of alcohol, feeling that the health benefits for a high blood-pressure male outweighs the health risks for neural or chromosomal damage at moderate levels.

    Of course, in many cases it is just an excuse to get away from exercises and get to the dinner table instead. :-)

    We protect ourselves against this societal malaise by taxing liquor heavily.

    Tax rates aren’t fixed by health concerns. Nor does taxes concern heavy drinkers that gets their alcohol by other means. Money is not enough as instrument when there is no linear relationship between consumption and risks or benefits.

    Tobacco is easier – no health benefits, only risks at any know dosage, even for third persons, and associated high costs. So why not prohibit it?

  7. #7 Martin R
    February 10, 2007

    What I meant was that the historical explanation for Sweden’s exorbitant liquor prices is actually our strong temperance movement around the year 1900. The workers’ movement had a strong temperance contingent, as its leaders understood that it would be impossible to organise the workers successfully unless they were at least half-sober. And it worked: the social democrats governed Sweden for most of the 20th century.

    Prohibiting tobacco would just lead to smuggling and other organised crime. Better tax it to death, as indeed we do. Few take up smoking in Sweden these days, most of them poorly educated young women.

  8. #8 daksya
    February 10, 2007

    The popular conception of the gateway theory relates the use of cannabis with the use of ‘harder’ drugs, rather than addiction to them. In that light, any gateway effect has to be mostly sociocultural and maybe economic as well. So the flaw with this study is that adolescent rats are forced to imbibe injected opioids/amphetamines at least once (the very first active lever press) after forced consumption of injected THC (note: pharmacodynamics of THC i.v. vs. smoked whole cannabis in rats isn’t discussed in the paper. Both the studies in the references deal with subjective discrimination in humans). Whereas in the real world, vast majority of cannabis users haven’t even tried heroin (97% as per NSDUH 2004 dataset). These type of studies do nothing to answer the generic question. This one in particular just tells us that if rats through the spectrum of adolescent development are forced to regularly consume injected THC, then upon being given a forced taste of opiates, they will consume more of it.

  9. #9 Torbjörn Larsson
    February 11, 2007

    The workers’ movement had a strong temperance contingent, as its leaders understood that it would be impossible to organise the workers successfully unless they were at least half-sober.

    That is the story I have been told too, and political concerns seems to have been guiding.

    Today it is another situation, since moderate amounts of alcohol in general and red wine especially has been shown (rather clearly, I believe) to possibly prevent heart diseases and at the very least correlate with long life.

    Usually food items with health benefits are subsidized, or at least not punished with special taxes. Here it is problematic since balance between benefit and utility is narrow compared with other food items. There is also more people that are seriously addicted to alcohol than food, I believe.

    Prohibiting tobacco would just lead to smuggling and other organised crime.

    Yes. But it would affect the moral view and clear all of the public space from secondary smoke problems.

    Since there is no lower limit established on risks, I think it is a legitimate action. Other cancerous substances are prohibited or regulated – tobacco is the exception, I think.

  10. #10 Torbjörn Larsson
    February 11, 2007

    “balance between benefit and utility” – balance between benefit and detriment

  11. #11 Martin R
    February 11, 2007

    Daksya: I agree, your analysis is sound. Perhaps the study’s results might be taken as support for the idea that if you find yourself among heroin users, then a history of cannabis use will make you more likely to succumb to heroin addiction yourself.

    A funny detail is that the study seems to disprove the “step ladder” hypothesis, where a junkie is thought to move step by step from beer to heroin. The stoner rats didn’t show increased interest in amphetamine.

    Torbjorn: are the beneficial cardiovascular effects of red wine comparable in magnitude to the risks of alcohol in general?

  12. #12 Martin R
    February 11, 2007

    Torbjorn: regarding tobacco, I think any prohibition move should be preceded by consideration of how many users enjoy tobacco in moderation. I have a feeling that anything that many people enjoy responsibly, in such a way that it does not lead to increased public expenditure (e.g. for health care), should be allowed to be sold as a matter of liberal principle.

  13. #13 Torbj�rn Larsson
    February 12, 2007

    Martin:

    Torbjorn: are the beneficial cardiovascular effects of red wine comparable in magnitude to the risks of alcohol in general?

    I don’t know, but it seems to be large enough that it is discussed (at least in the tabloids) as a possible ordination.

    What I believe may be a possible find is correlation with longer life for whatever reason. It could be that the effects are positive, or at the very least they aren’t very prohibitive for moderate drinkers that would live a longer life than abstainers or heavy drinkers in any case. But the last alternative raises new questions.

    You are a skeptic, so you would likely like to see the research here. At this moment, I would too. Frankly, I haven’t kept up to date with these questions lately. However, it is too late today to dig and get a reasonable update.

    “I have a feeling that anything that many people enjoy responsibly, in such a way that it does not lead to increased public expenditure (e.g. for health care), should be allowed to be sold as a matter of liberal principle.”

    I agree. However, I suspect this is not the case here.

    In comparison, I worked in Texas 92-94. Granted that sidewalks weren’t common, never the less it was extremely rare to involuntarily inhale smoke. I believe fear of litigation, and such rules as no smoking within 10 m from no smoking entrances, made this possible.

    In Sweden I will be subjected to smoke or ash quite often, especially around public transportation, due to lack of adequate non-smoking rules and enforcement in the public sphere. I think that is totally unacceptable considering that already one cigarett is harmful, secondary smoke is more harmful than filtered primary smoke, and no lower limit for harmful effects has been found.

    And AFAIK the tax income here doesn’t come close to compensate for public expenses in health and loss of work.

  14. #14 daksya
    February 12, 2007

    Torbj�rn Larsson’s characterization of tobacco as “no health benefits, only risks at any know dosage” is inaccurate. It’s most probably symptomatic of the culture we live in that we require simple rigid categories to classify things in. Tobacco has been branded a common villain and is the convenient victim of this tendency.

    To rebut his two charges:
    1)’only risks’ – the landmark British 50-year longitudinal study on male British doctors showed that the cohort which smoked for an average of 10 years in a pattern similar to longer smokers (15 cigs/day), showed no excess mortality. The cohort which smoked for 20 years showed slight excess mortality. The problem isn’t with tobacco or even smoking tobacco per se. It’s to do with the combination of modern fast-paced Western life, psychopharmacology of nicotine, and most instrumentally, cigarettes as the delivery device. Cigs are very portable devices that easily allow you to imbibe a substance which leaves you functional but unfortunately whose offset occurs relatively quickly, thus forcing chronic intake and hence gross consumption over one’s lifetime of volatalized carcinogens. And it is this gross consumption that leads to higher risks for all sorts of diseases. Tobacco taken in social rituals and in other non-smoked forms don’t lend themselves to such use and are unlikely to pose anywhere near the same magnitude of risks.

    2)’no health benefits’ – open any recent neuropharmacology textbook and read about the protective effect of nicotine regarding Alzheimer’s disease.

  15. #15 Torbjörn Larsson
    February 13, 2007

    the cohort which smoked for an average of 10 years in a pattern similar to longer smokers (15 cigs/day), showed no excess mortality.

    Of course there are studies which deviates. The one I mentioned with 1 cig/day being harmful may be one. But that smoking and secondhand smoking is harmful and kills is AFAIK well established.

    protective effect of nicotine regarding Alzheimer’s disease

    Nicotine has medical (duh) and even positive effects in some cases. I was of course referring to normal use. Nicotine is also damaging on the skeleton, which is why it can’t be used indiscriminately.

    And don’t forget that cigarettes is a stupid delivery system for a medicine. More precise and less harmful alternatives are available.

  16. #16 daksya
    February 13, 2007

    Torbj�rn Larsson: The one I mentioned with 1 cig/day being harmful may be one.

    Where?

    But that smoking and secondhand smoking is harmful and kills is AFAIK well established.

    It’s not. Saying “smoking kills”, like I pointed out, is an application of naive categorization. You smoke above a certain amount and you become part of a group among whom some will die prematurely. You smoke some more, and you become part of a group among whom a larger fraction will die prematurely. Smoking is not a magical poison that kills indiscriminately at any dose.

  17. #17 Torbjörn Larsson
    February 14, 2007

    Where?

    Oh, it was an IIRC. I’m pretty sure you can find many papers on tobacco smoke with harmful effects lower than the one you cited, as you seem to argue that “[t]he problem isn’t with tobacco”.

    Saying “smoking kills”, like I pointed out, is an application of naive categorization.

    I didn’t mention dosage, you do. And as I said, it seems no lower dose is established.

  18. #18 daksya
    February 14, 2007

    I didn’t mention dosage, you do

    Actually, you did, when you said, “no health benefits, only risks at any know dosage” and then you claimed that you cited a study showing that even 1 cig/day led to increased risk (“The one I mentioned with 1 cig/day being harmful may be one“) but, of course, there’s no mention of that study.

  19. #19 Torbjörn Larsson
    February 15, 2007

    Actually, you did, when you said, “no health benefits, only risks at any know dosage”

    And how is that dose specific?

    there’s no mention of that study.

    No. Usually I would say “Let’s find out”. But this is such a large subject and such an uninteresting detail. Soon we will be discussing linear or threshold models instead of facts.

    If you want to make an effort to find out if there is a minimum dosage for your own sake, please do so.

  20. #20 daksya
    February 15, 2007

    And how is that dose specific?

    You are claiming that there is no lower limit. And then later on mentioned something about a study showing even 1 cig/day being harmful, but which you haven’t cited.

    But this is such a large subject and such an uninteresting detail.

    You are advocating for tobacco prohibition on the basis that “no health benefits, only risks at any know dosage”. How is it an uninteresting detail?

    If you want to make an effort to find out if there is a minimum dosage for your own sake

    I already did. The British Male Doctors study has this instructive figure that encapsulates my point.

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