Again with the Marijuana

Blogging on Peer-Reviewed Research

What is it about reporting on pot that makes people so Puritanical? Today I read in the Guardian Cannabis joints damage lungs more than tobacco - study.

A single cannabis joint may cause as much damage to the lungs as five chain-smoked cigarettes, research has found.

Is that so? Let's take a look at the data.

The authors of the article compared smokers to fairly heavy marijuana users - based on the mean smoking exposure of the groups (54.2 joint years compared to 23 pack-years for the smokers both with a mean age ~42-46) the group was clearly smoking multiple joints a day over decades while the smokers - based on mean age and use - were probably smoking a little less than a pack a day on average. This first figure shows the many variables they examined using their method of high-resolution CT scanning that allowed them to quantify changes observed in the lungs, as well as some more classic techniques.

i-facdc76f0b5b6956a3727264bb1c9a29-Thoraxfig1.jpg

It's been a while since I've taken respiratory physiology, but I think we can make it through this figure OK. The first set of numbers are area measurements from CT slices of the patients lungs, and an evaluation of whether or not there are macroscopic changes in the lungs consistent with emphysema. It shows that tobacco smokers get emphysema at a rate about 17 times that of marijuana smokers, and that's if you consider that 1.3 % to be statistically significant, which it isn't.

The second set of data comes from plethysmography (great word huh?). You have the patient blow air into a tube and measure their ability to push air out of their lungs, as well as the volume of air they are capable of moving in and out. In emphysema for instance, you have a large lung volume, but because of the loss of elasticity of your lungs you have little ability to push it in and out of your body. For the most part, the tobacco smokers did the worst in these tests, although the pot smokers showed some decreased lung function.

The third set is mostly subjective data about symptoms of coughing, wheezing etc., that the patients experience. Again, in most measures it was the cigarette smokers that consistently performed worse across the board.

Now this is interesting. The Guardian article makes a big deal about how smoking a joint is 2.5-5x worse for your lungs - based solely on changes in some of the lung function tests - however only the smokers show signs of emphysema. Is this really a sign that pot is worse than cigarettes?

Surely, if you smoked pot like cigarettes - 20-25 times a day - the data suggest that you might experience more significant airflow changes. However, no one smokes that much pot. It's a very different drug from cigarettes and people don't smoke all day - while driving, while working, while eating etc. - which allows the tobacco habit to become so dangerous. Further, no one has been able to link marijuana smoking to emphysema, COPD, or lung cancer (even in very heavy users) while cigarettes show a striking increase in risk for many smokers.

It is biologically plausible to think that smoking marijuana is ultimately a risk factor for lung cancer - albeit much smaller than for cigarettes - and I don't think it can be ruled out. Studies like this one and others do show there are negative health consequences to smoking marijuana - bronchitis, wheezing, cough etc. Putting smoke in your lungs, any smoke, is worse than no smoke at all of course.

But to make these comparisons that pot is somehow "worse" than cigarettes simply can not be justified. Marijuana is not physiologically addictive (it doesn't cause serious withdrawal) like cigarettes and other drugs, it does not have an established cancer risk and even the heavy users studied did not show signs of emphysema and COPD. Basically they showed some changes in lung function associated with their habit of inhaling marijuana smoke, but it wasn't as bad as being a smoker, and doesn't seem to cause emphysema like smoking does. Pointing out that the changes in one ratio of lung function tests and calling pot 2.5-5x worse seems misleading and unnecessarily alarmist.

What is it about covering the marijuana beat that makes people lose their objectivity I wonder? Rather than spending their time studying the health effects of marijuana, which have been persistently shown to be slight, maybe they should study the real risks of the drug - listening to bad jam bands and being socially boring.

1. Aldington, Sarah, Williams, Mathew, Nowitz, Mike, Weatherall, Mark, Pritchard, Alison, McNaughton, Amanda, Robinson, Geoffrey, Beasley, Richard
THE EFFECTS OF CANNABIS ON PULMONARY STRUCTURE, FUNCTION AND SYMPTOMS
Thorax 2007 0: thx.2006.077081

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"the real risks of the drug - listening to bad jam bands and being socially boring."

Thank you for at least the implication that not all "jam bands" are "bad." As for being "socially boring," I...
wait...

what?

By Sven DiMilo (not verified) on 31 Jul 2007 #permalink

Pete, you might like this one as well.

Medical hypotheses is hysterical. It's a mixture of complete idiots publishing nonsense, and the occasional person with enough time and sense of humor to bother sabotaging them.

I think both of these papers might be the latter.

This is one case where one has to strongly consider pressure from those higher up to fudge the findings to make them "look" like they want them to. Since the days of Refer Madness, there really **has** been a concerted effort of specific groups in the government to distort facts, lie, pressure people into misreporting information on Marijuana (and any other unacceptable drug), and if necessary and possible, cut funding or otherwise *stop* research or reports that contradict what those groups want said. I wouldn't be surprised if these people intentionally misreported the data, knowing that reporting the right thing would get them harassed, and that people who understand the data better would *still* see that the data actually says the opposite. The fools that work so tirelessly to undermine real data on the subject probably don't know how to read the data anyway, and just look to see if the right buzz words are used to demonize the drug, while persisting in the equally biased delusion that cigarettes are not so bad after all.

Sometimes the problems isn't if you are paranoid, its that you are right. And in this case, I think you can make a strong case that a real conspiracy exists. After all, the government **still* provides two of its own employees with Marijuana for those "non existent" medical benefits, even as its spent most of those people's lives telling is it a) has none, is b) is as addictive as the other drugs and c) its a bad bad thing to have or sell it. Odd that...

Hmm. On a side note, I really need to stop trying to change direction in the middle of sentences.. Kind of almost unintelligibly messed up bits of that last point. lol

and what is it about blogging the marijuana beat that causes you to lose all objectivity? "serious withdrawal" "like nicotine and other drugs" (such as???) is the only sign that something is "physiologically addicting"? now you sound like a denialist mark...

science is science. you look at the data and ignore the hyperbole. someone finds a function for some damn transcription factor and trumpets how this is going to lead to all kinds of wonder therapies. it hardly ever does. yet you don't get all het up about this, do you? so why is marijuana so especially of interest?

Woah Drugmonkey. How is marijuana physiologically addictive? Nicotine and other drugs have serious problems with addiction. Withdrawal from nicotine is miserable, cocaine and alcohol withdrawal can be lethal, heroin withdrawal is excruciating. Pot? Not so much.

There is not a similar physical dependence of marijuana compared to any of these drugs. Psychological dependence maybe, but physiological addiction has not been firmly established in humans or animal models. Most former users will tell you the same, and the physiologic effects of dependence appear to be reversible after abstinence, unlike alcohol, cocaine, tobacco etc.

As far as transcription factors go, they don't usually make every single major newspaper with alarmist messages about schizophrenia and lung damage.

Thanks for these posts Mark. I'm more and more realizing just how pretty much every study that bad-mouths pot is fudged in someway, and any report that is positive for pot in some form is more likely scientifically accurate. Science reporting shouldn't be that way, but it's sadly what I'm seeing far more often than not.

Excellent dissection of the BS fed to the bovine masses to incur a shock reaction and instil an even more illogical and ignorant perspective on what should be another socially accepted form of interaction but because it can't be regulated and cheapened with mass production like tobacco and alcohol, quite simply isn't. A big thumbs up!

Delmorpha -

What's really silly, is that it can in fact be regulated and mass produced, just like alcohol and tobacco. Honestly, I might actually go to a bar, if they had vaporizers or a toking lounge, with pre-produced marijuana cigarettes. As it stands, the only way to get me into a crowded bar, is through the back and onto the stage. Can't handle the crowds to save my life, unless I'm performing in front of them - strangely doesn't seem to bother me then.

Mark,

As someone who spends a deal of time trying to parse the actual risks of drugs of abuse scientifically, I find misuse / ignorance of the available science distasteful. From the perspective of the legalization / decriminalizaion advocate as well as from the ReeferMadness type. Denial of the available evidence or wildly hyperbolic extrapolation alike.

The full response got a bit lengthy.

Cross-posted at Drugmonkey's site:

Im not a member of the legalize it crowd. I believe in decriminalization of drugs, but not legalization.

Im not sure how to address your strange dualism argument. There are distinct physiological mechanisms associated withdrawal from other substances - increased heart rate and blood pressure, hallucination, delusions, amplified pain, etc. The withdrawal from two drugs in particular, alcohol and cocaine is actually quite dangerous. With the DT, death occurs 1-5% of the time even with treatment, as much as 20% of the time without. Cocaine is similarly dangerous and people should go to treatment centers to quit.

Yes there is an endogenous cannabinoid receptor system that adjusts to THC use, grows tolerant and dependent. But what are the symptoms of cannabis withdrawal? Irritability and insomnia. Hardly the end of the world. There is a matter of degree here that is not being considered.

Come back when pot has people selling their bodies for a hit or laying around on the street begging for change like meth or heroin. Or when the withdrawal is so severe that it leads to significant morbidity and mortality. Then Ill worry about it. In the meantime, jonesing for a joint has not yet made it to the DSM-IV, and while they may write papers about a marijuana withdrawal syndrome, its clinical relevance is considered minimal.

I dont mean to be a pain in the ass, and Im not trying to deny the existence of a group of people who need to seek treatment to get off pot. I suspect, however, the withdrawal from marijuana isnt as important as just isolating them from their peers.

crosspost:
MarkH: You are the one that advanced the dualism argument about "physiological" and �psychological" dependence. What exactly does "psychological dependence" mean to you? Is insomnia "psychological"? Are affective phenomena somehow less "real"? It is apparent from your comments here that you in fact recognize my point that cannabis does indeed induce dependence. Your post and initial comment give an entirely different impression. I'm trying to point out that your rhetorical tactics in the post and the comment are similar to those you debunk to some extent elsewhere on your blog. The commenter who said essentially "see, markh's critique of the MSM sensationalization of this one paper shows that all cannabis research is bullshit at core" shows the problem very nicely.

I am not arguing one bit with comparisons on the relative severity of the most extreme or even mean severity of heroin or alcohol or cocaine discontinuation. This is not the point regarding treatment of the underlying science. Just so long as your comparison does not include inaccurate representations of the cannabis side of the equation and likewise includes realistic and not cartoonish and most extreme examples of the withdrawal symptoms of alcohol or heroin.

Your comment here about getting dope smokers away from their peers and relative priority of acute withdrawal symptoms betrays a misunderstanding of addiction. These are relatively fixable problems. People can be detoxed through the acute withdrawal phase quite easily and, relatively speaking, cheaply. A matter of weeks. It is also possible to avoid the wrong friends. If this was all it took we wouldn't have a problem with dependence, at least in the population that is motivated to quit. The trouble is relapse. Driven in most cases not by the friends that offer you a hit but by an internal motivation state to start consuming again. Craving so to speak. There are data. Any experience addiction clinician can tell you this is a major problem. What this tells us is to make sure to be looking at the right phenotype when comparing relative risk for dependence.

Woah. You know I think the problem here might be grammatical. Here is what I said:

Marijuana is not physiologically addictive (it doesn't cause serious withdrawal) like cigarettes and other drugs

Now, I see how this could be interpreted as "no physiologic addiction" - and I think the parenthetical statement made this sentence seem stronger than I intended. My intent was to say the physiologic effects of marijuana withdrawal were not like cigarettes and other drugs, not that it does not exist at all. It does cause withdrawal, albeit minor. Most drugs do. You can become dependent on aspirin or NSAIDS for instance, and the rebound headaches from withdrawal can be a nightmare. People have been known to become dependent on nasal sprays. The question is of relative severity of the withdrawal.

Psychological dependence refers to behaviors of drug seeking and a desire to experience the high - I would describe craving and drug seeking as signs of psychological dependence. Physiological dependence refers to things that are less subjective. I'm sorry if you don't like the language, that's just the way they taught me in medschool. I suppose it suggests duality, but that is not intentional and it's the way I still think of it. If there is better language to differentiate between symptoms such as craving and drug seeking and anxiety vs. more directly measuraable phenomena of withdrawal such as sedation, increased or decreased blood-pressure heart rate etc., pain hypersensitivity, vomiting/constipation etc., tremor, seizure and stroke, I'd like to know what it is.

But you also said
There is not a similar physical dependence of marijuana compared to any of these drugs. Psychological dependence maybe, but physiological addiction has not been firmly established in humans or animal models.

My point is that the functions of the brain are both physical and physiological and that so called "psychological" phenomena result from the physiological and physical state of the brain. Your distinction is artificial if it is not in fact closet or subconsciously (psychological!) dualist. The question is, why do you use it and why were you trained to use it? More importantly, what is the result on your thinking and interpretation of data? To this latter I would suggest it is a minimization of health concerns that are not "directly measurable" as you put it. Surely you recognize this as a common critique of the medical profession.

As to replacement terminology- why do you require this classification scheme? Isn't it enough to simply refer to cardiac, affective, motivation, etc symptoms? to be even more specific about blood pressure or depressed mood? Shouldn't the physician be interested in all possible health concerns?

Most former users will tell you the same, and the physiologic effects of dependence appear to be reversible after abstinence, unlike alcohol, cocaine, tobacco etc.

really? "sedation, increased or decreased blood-pressure heart rate etc., pain hypersensitivity, vomiting/constipation etc., tremor, seizure and stroke" don't remit with long term abstinence from alcohol, cocaine and tobacco? come on. this is not even remotely defensible. The most lasting and consistent "problem" associated with drug discontinuation is the prepotent urge to resume retaking drug. period. essentially permanent experience of the "directly observable" symptoms you list are comparatively much much rarer if they exist at all. Does you local AA meeting feature a bunch of folks bitching about how they just can't stand that elevated blood pressure or living on the verge of seizure every day? heck no, they talk about the urge to drink.

drugmonkey i take it u never had first hand experience in a plethora of drugs over extended periods of time...
when you do you will change your mind.
Claiming that all the damage done by drugs are reversible ? try to tell that to cocaine and alcohol abusers who are on DISULFIRAM, Suboxone and other replacement therapies.
The idea here is that their craving is due to physiological need not a psychological need like with THC.

bambam, I doubt it. There is no useful distinction here between "psychological" and "physiological" "need(s)". I did not claim that all the damage done by drugs is reversible. I was responding to MarkH's apparent point about "physiological symptoms". My point was in fact that that craving remains long after the vomiting has remitted.
MarkH corrected his comment and apparently means to say that craving for THC remits while it does not for other drugs. This is crap. Some individuals dependent on THC have big craving problems long after discontinuation. Ditto just about every other drug of abuse that we typically consider. Likewise, some individuals who abuse just about any drug you can think of , yes including nicotine and heroin and alcohol, can quit with no lasting craving problems. There is NO qualitative distinction. All that exists is a quantitative one. How many people? What course of exposure? How severe the symptoms? The character of the symptoms. etc. But the argument that THC is categorically different from other drugs, to argue that all dependence related phenomena just go away in all people for this one drug is just plain erroneous.

MarkH corrected his comment and apparently means to say that craving for THC remits while it does not for other drugs. This is crap. Some individuals dependent on THC have big craving problems long after discontinuation. Ditto just about every other drug of abuse that we typically consider.

I don't know if I agree with this drugmonkey. There are multiple instances of dependence on drugs that once the withdrawal is beaten there is no significant craving. Dependence on NSAIDS would be an example. I suspect caffeine is the same. Compare that to nicotine, cocaine, or heroin in which the sight of the drug triggers cravings in addicts long after they've come clean.

This is extending well beyond my experience and knowledge however. I don't think that all example of dependence and subsequent craving are irreversible. This doesn't strike me as being believable, but I would have to find some research to back it up.

Way to make pot smoking boring guys.

Smoking one cannabis joint caused damage equivalent to smoking 2.5 to five cigarettes in rapid succession, researchers at the Medical Research Institute of New Zealand found. Doctors who carried out the study believe the damage is linked to the difference in the way cannabis is usually smoked, with users inhaling hard, holding their breath for longer and failing to use filters.

Check, check, check. Even back in the 70s it was a well passed around rumour that one J was the eqivalent of three cigarettes. So many didn't smoke cigarettes; why add to the grief.

I woulda figured that with the more potent weed available these days, the deep inhalation and shotgunning wouldn't be needed. But it appears that there's a predisposition to supersize the experience, no matter the quality.

I don't think that all example of dependence and subsequent craving are irreversible. This doesn't strike me as being believable, but I would have to find some research to back it up.

you are being too absolutist about it which is likely my major problem. i agree, not all *people* who are dependent on a given substance are going to have lasting problems. however *some* are. regardless of substance. there is nothing special about THC in this regard. you seem to take the position that presence or absence of lasting craving can be categorized by the substance instead of by the user. I think this is unsupportable.

I think you are also a bit off with your subjective feel for the relative scope of the problem because you are ignoring the base rate and the appreciable conditional probability of dependence to focus on the fact that this latter is likely lower than for coc/heroin/nicotine and the like.

I have a colleague who recently opened a study requiring treatment-seeking cannabis users. first, it was very quickly oversubscribed meaning they had an abundance of qualifying subjects. this isn't all that common in human studies, you frequently have to pound the pavement a bit more than just putting a simple ad in the paper. second, once the subjects go abstinent, they have a host of withdrawal signs, not all of which are "psychological" as you'd have it. this is not a long term abstinence study but the early going suggests that craving is very much part of the picture with respect to their inability to quit.

By Drugmonkey (not verified) on 02 Aug 2007 #permalink

I will look forward to seeing the results of that study.

In the meantime how about this as a final statement.

Marijuana creates dependence in users but the clinical significance of abuse and withdrawal is less than that of other drugs of abuse like cigarettes and alcohol.

Does that sound fair?